Snakes are often divided into the broad categories of venomous and constricting, but there’s also a swathe inbetween with miscellaneous tactics. The long-nosed snake of northern Mexico and the parched southern US is one of several that simply pins its prey to underground tunnel walls. This snake lives in semi-deserts, dry grassland, and especially dry shrubland, and is a burrow invader which winds through underground tunnels in search of small lizards and occasionally mammals to eat. They’re guided by scent, and either find the chamber where an exhausted lizard is sheltering, or get lucky and find one running around the wide tunnels.

The long-nosed snake then springs into feeding mode, reacting in milliseconds. They pounce on their prize, but rather than tightly constricting, they pin their prey to the wall, using all the force they can muster. The initial wall slam doesn’t necessarily kill the lizard or mouse, and there’s a strong chance they could wriggle free. But if all goes to plan, the long-nosed snake will have its meal, without any venom, just pure acrobatic skill. It’s like venom is a modern invention which they have no patience for, and they’d rather just pin things down like the good old days. 

Long-nosed snakes are harmless to humans, lacking even a mild venom. When confronted, they angle their colours towards your face to trick the unaware into thinking they’re coral snakes. 

The ladder snake is a 100-150cm species of Spain, which moves slowly the vast majority of the time, except for when it lunges to pin a small mouse to a tunnel wall. This burrow invader lives in dry countryside areas, and is sometimes encountered by nature enthusiasts crawling along dry stone walls (the snake that is).

Ladder snakes are non-venomous, but have a vicious bite when confronted by humans, and resist any attempt to pick them up. Their hunting strategy is to fleck their tongues for mammal scents, and eat them as they sleep, or track one through the tunnels and pin it to a wall. Ladder snakes are very accurate; there’s a chance that a mouse might wriggle free from their grip, but they’d have to get very lucky.

Snakes may have no limbs, but they have surprisingly high control over each area of their long body, allowing them to pin creatures accurately. Although not confirmed (seeing as these underground battles are rarely observed), they almost certainly gain skill with age. For example, spitting cobras are usually wild and inaccurate with their sprays as hatchlings, but gain precision after a few years. Ladder snakes mostly prey on mammals, with 5-15% of their calories coming from birds. 

This expert wall pinner lacks even a mild venom. They’re a creature of Ugandan woodlands and savannahs, and usually loll out a dark black tongue to intimidate their enemies when cornered. Their diet consists of mice and rats, and to find their next meal, they’ll search far and wide, including in dark burrows. The grey beaked snake enters a subterranean world, guided by subtle scents, until the first small mammal finally comes into view. They then pin them to the wall and swallow whole. Grey beaked snakes have been found with 4 mice in their belly at once. 

It’s extremely important for grey beaked snakes to pin their prey as soon as possible. A mouse’s best hope of survival is to use its agile reactions to dart to the side before the snake makes contact. It’s do or die, and they have just milliseconds to react.

If a mouse gets pinned, their chances of survival plummet, not to zero, but somewhere close. Over the ages, grey beaked snakes have likely gained sharper reactions themselves, to combat these agile mice. But they sometimes meet one which is a cut above the rest and harder to pin down. This is what we assume, as Scaphiophis albopunctatus is a relatively poorly researched snake. Pinning mammals to burrow walls is one of the few hunting facts we know. 

The gopher snake is one of the most shameless invaders of mammal burrows. They reside in the fields, woodlands and plains of the western USA, and are non-venomous, though quite vicious when they meet humans. The gopher snake has a heavy taste for mammals, and will stop at nothing to ambush them. If that means searching through burrow networks, they won’t hesitate. Gopher snakes are constrictors, but their movements are restrained while underground. Therefore, if a gopher snake sees a mouse, it will instantly pin them to the burrow wall, holding them in place, with a move practised over many years, honed to razor efficiency. 

To do this, have a larger arena than you might think. These burrows probably measure no more than 20cm, but to a snake they’ll look as a large as a mine tunnel or a hidden WW2 bunker. If a vole leaves the safety of its nest chamber, then it knows that a giant snake could be around any corner. It’s a labyrinth, and deciding the right way is essential. Otherwise, they could end up pinned to a wall so fast that there’s no time to comprehend what’s happening. 

The same is true for the snake itself. To humans, basilisks are creatures of mythology, but to voles in a tunnel, every snake probably looks as large as a basilisk. It’s debatable whether mice have the intelligence to pick up a small stone, throw it in the opposite direction, and distract the blinded snake with the noise. The only advantage small mammals have is knowing their burrows like the backs of their hands.

The woma python, or simply woma, is a creature of the Australian outback, occurring in pockets all over the barren centre to Shark Bay on the west coast. They’re recognisable by faded striped patterns, a bulky head and large eyes, and are no danger to humans, unless you poke your finger into their mouth.

The woma python is rarely seen climbing trees. They prefer to travel downwards, entering the earth’s crust through burrow entrances carved by rodents. When they find a loose mouse scurrying around them, they reveal why they’re part of the brutal side of nature: they seize the mouse, pin it to a wall, angle their mouth correctly, and swallow them whole. The woma python takes care to pin its prey very precisely, so that they don’t slip free.

Escape isn’t the only thing they have to worry about. Rats or mice can also attack, biting through a snake’s scales, gnawing on its body like a block of cheese. A woma python might fight through the stinging pain, determined to acquire its meal, but rodents are vicious enough to kill snakes if accurate. The snake might be forced to back off and go hungry for another day. Many adult womas have visible scars from these gnawings, which last for the rest of their lives. 

Part of the same Pituophis family as the gopher snake. Louisiana pinesnakes also pin their prey to burrow walls (which scientists call “pinioning”), but this time, they’re highly targeted towards one prey: the pocket gopher. Louisiana pinesnakes are highly endangered, and inhabit only western Louisiana and extreme east Texas. They’re dependent on longleaf pine habitats, which are steadily shrinking except in protected pockets. Louisiana pinesnakes love to invade burrows in these forests, disappearing into dark tunnels in pursuit of the gophers which forge them. Louisiana pinesnakes have a permanently hungry expression, and are more acrobatic than they look. When a gopher comes into view, they can defy expectations and pin it to a wall instantly.

Louisiana pinesnakes carefully maintain the pinning pressure until they unhinge their jaws and swallow. This species lacks any venom, not even a mildly venomous saliva, and all their evolutionary focus has gone into muscular strength. As usual though, they’re not infallible. Louisiana pinesnakes are much longer than the mammals they’re trying to pin, giving them less wiggle room.

Gophers also have far more detailed knowledge of the tunnel networks. If the snake isn’t careful, their prey might slip into a side passage, which is far too narrow for them to fit down. The disappointed pinesnake would have to reverse all the way out of the burrow, cursing its luck. The pocket gopher, meanwhile, would be panting in its dark chamber of safety, realising just how close it came to its doom.

A 100-140cm snake native to southern China, where it enjoys truly spectacular views, or would do if it wasn’t so keen to invade underground burrows. Mandarin ratsnakes are rarely seen, as they mostly lurk in subterranean tunnels. Most captured by humans still have particles of soil clinging to their scales. They’re timid in the presence of people, but show no such fear amongst their underground mammal prey. 

The Mandarin ratsnake likes to pin rodents hard to a tunnel wall, after crawling through the passageways slowly and undetected. They then take just seconds to rearrange and swallow, giving the mouse a tiny window to escape. All their focus must be towards agility, as Mandarin ratsnakes lack even a mild venom in their saliva. As ever, they can spring into life extremely quickly, as though they’ve saved all their energy for this one pinning.

Such snake-mammal duels can take place near the entrance or deeper within the tunnels. It wouldn’t be surprising if the resident ants and earthworms came out to secretly watch. Some might crawl past, staying silent, hoping that the brawling snake doesn’t notice them. A crowd could gather, with many interested worm heads poking out of tiny gaps in the tunnel walls. The snake probably has many moves as well, such as a tail sweep, or a straightforward body slam to act as a finisher. Likewise, the cornered mouse might throw in a wall kick, or even a backflip. This is all pure speculation of course, as Mandarin ratsnakes aren’t well researched, aside from the burrow pinning basics. One day, we could witness these battles properly, when cameras become tiny enough to be placed in mice burrows by scientists.

This ubiquitous eastern US snake has many hunting tactics: ambush, chasing down, crushing constriction with several coils. However, it’s equally skilled in the primitive art of pinning a mouse very hard to a tunnel wall, and rearranging itself to swallow.

Common kingsnakes are non-venomous, and usually flee or vibrate their tail against leaves when they meet humans. They’re commonly hunted by birds on the surface, making burrows both a sanctuary and hunting ground. Common kingsnakes have super sensitive smell, to compensate for the darkness of tunnels. They possess a wiry strength, which belies their relatively thin bodies. As a whole, kingsnakes are significantly stronger than US ratsnakes. This enables them to slam mammals down with a force which is extremely difficult to escape from.

The only downside to this brute strength is potentially collapsing the tunnel wall. There’s no guarantee that every burrow is completely solid. If a common kingsnake accidentally selects a fragile wall, then pinning a mouse against it could leave both buried in a calamitous mound of soil. After shaking its head free of dirt, the snake might find that its mammal prey is gone. The snake could then decide that it’s too risky to carry on, and reluctantly retreat to the surface, empty-handed. Particular favourites of the common kingsnake include Ord’s kangaroo rats and hispid cotton rats.

An evolutionary relic of a snake, which is the sole member of its family, and actually closer to the boas. Calabar burrowing pythons live in central western Africa, particularly Nigeria. This non-venomous snake searches actively for prey rather than ambushing, and this quest often leads them into burrows.

Calabar burrowing pythons have been observed eating the Temminck’s mouse and the ubiquitous black rat, with mammals comprising 80% of their diet. The Calabar burrowing python disables its prey the hard way. Cobras have neurotoxins which can paralyse mice in seconds, but this leathery snake prefers primitive grab and pin strategies. It rams a mouse towards the tunnel wall, holding it down using all its scaly, sinewy strength. 

The last thing the mouse sees will be a honeycomb pattern of gold and black scales. That is, unless a sudden instinct to live awakens inside them, and they dash to the side using superhuman speed. If the mouse succeeds, they have several choices: they could duck under the snake’s body, or they could clamber over its head, using its scales for handholds, before dropping down the other side and making a desperate dash for safety, with a furious hiss behind them which they don’t dare turn around and look at for even a second. Calabar burrowing pythons are technically constrictors, but are relatively clumsy at it – hence the burrow pinning strategies. 

A common snake which inhabits most of Central America, into far southern Texas. This species inhabits forest and field alike, anywhere with soft soils and burrows which it can invade. The middle American indigo snake disregards venom, and sticks to the tried and tested business of pinning its prey to an underground burrow wall. Its diet is varied, with mammals making up the largest share, plus a side helping of rattlesnakes. They use similar methods to gopher snakes, pinning with a loose coil while angling their head round in order to swallow. Drymarchon melanurus is non-aggressive towards humans, but to large rats, they’re a bogeyman. 

The Middle America indigo snake has very fast reactions for a creature that normally slithers at moderate speeds. However, they’re not infallible, and things don’t always go according to plan. The snake might pin its prey slightly off centre, or the wall the rat is pinned to might be slightly uneven. This affords the animal just the slightest opening it needs to wriggle with all its might, and burst free with adrenaline surging through its body, the rodent scurrying away rapidly while the snake struggles to rearrange itself.

If a snake always used the same burrow, then it would be different, as they would know every nook and cranny inside out, like a golfer and his favourite course. However, indigo snakes must follow scents, and are constantly drawn to all-new burrows. Each one is an unfamiliar obstacle course, which they must rapidly get to grips with, if they want any chance. Another unfortunate event could be when smells lure them in, but the burrow is long vacated. The scents are old ones which have accumulated over many months, which snakes are extremely sensitive to. The Middle American indigo snake slithers into unfamiliar burrows without any fear whatsoever.

The Bungarus kraits are a family spread far and wide across southeast Asia. Rather than athletic chargers, this is a group of night crawlers. Bungarus kraits grind stealthily along the ground, and often invade houses or workers’ constructions huts while the occupants sleep. The longest of this group is the banded krait (Bungarus fasciatus). This species ranges from northeast India through Thailand to Indonesia, and reaches a confirmed record of 225.5cm, with an average of 120-150cm.

Like other kraits, its venom is loaded with neurotoxins. Confirmed ingredients include the post synaptic neurotoxin α-elapitoxin-Bf1b, and the pre-synaptic neurotoxins P-elapitoxin-Bf1a and beta-bungarotoxin. Banded kraits are more than capable of killing you, should one sneak into your garden shed at night where you’re trying to finally finish your book while your family sleeps. Banded kraits can achieve the following: disable connections between lungs and brain, paralyse limbs, cause drooping eyelids, and a tsunami of nausea. 

One confirmed death happened in Myanmar. The victim experienced very few local symptoms, such as swelling or necrosis. Yet neurotoxic symptoms arrived within 2 hours, and the victim died of respiratory failure 14 hours post bite.

The Bungarus krait family has 16-20 members and Thailand has 3. At 225.5cm, banded kraits easily exceed its rivals in maximum length. In Thailand, the red-headed krait peaks at 195.5cm, while the Malaysian blue krait (the deadliest of the 3) peaks at 175cm.

These three species are easy to distinguish from each other. Blue kraits are black and white, while red-headed kraits are very dark blue with a red head. Meanwhile, banded kraits are black and yellow, with orderly stripes. But banded kraits are by far the easiest to distinguish from all other snake species. The other two have many non-venomous or mildly venomous copycats. Red-headed kraits have pink-headed reed snakes, while blue kraits are mimicked by banded wolf snakes.

No snakes in Thailand have the dense yellow and black spacing of Bungarus fasciatus. The closest is the Laotian wolf snake (Lycodon laoensis). This is also a pure yellow and black, and probably evolved to convince forest creatures it was loaded with neurotoxic venom, when its deadliest weapons are actually sharp teeth and playing dead. However, Lycodon laoensis has far wavier bands (see here). Instead of disciplined and orderly, they look like they’re reflected in a funhouse mirror. Also, the black sections are more much longer than the yellow, unlike in banded kraits.

Banded kraits rarely climb trees, and swim only occasionally, mainly to drag watersnakes out of muddy holes in the shores. This is a ground snake through and through.

Banded kraits are heavily nocturnal, and during the day, they’ll rest in dark sheltered hideaways, particularly vacant burrows and termite mounds. Poking your arm into a dark Thai burrow is a foolish idea, one that could end in your untimely demise, but not because of the creature that forged that burrow – because of sneaky kraits taking them over.

Like other kraits, Bungarus fasciatus flips a switch when night falls. Under moonlight, all their aggressive instincts are awakened, and Bungarus fasciatus bites at will, particularly if touched in any way. While they don’t rear up and make stabbing lunges like a cobra, they’ll turn aggressive if they deem their personal space to be invaded. By day, however, banded kraits are timid and sluggish. They rarely strike, and will only sink their fangs and squeeze the attached venom apparatus if they feel severely threatened.

Bungarus fasciatus causes far fewer bites than the monocled cobra, white-lipped pitviper, and their relative the Malaysian blue krait. A 9 year Thai study illustrated this well. The survey scanned patients from Ramathibodi Poison Center in Bangkok, to establish symptoms and survival following krait bites. The cases involved the following species: Malaysian blue krait (68), banded krait (7), and red-headed krait (1).

Bungarus fasciatus beat the notoriously secretive red-headed version, but fell way short of the blue krait. The study also revealed the symptoms. Luckily, 3/9 victims received a dry bite, a miraculous fang gnashing where no venom is injected, and that’s an unusually high percentage across the snake kingdom. Of the 6 who were envenomated, none died, but 5 suffered respiratory failure to such a degree that they required intubation and mechanical ventilation.

The average number of antivenom vials administered was 9 per patient, with a range of 3-20. The mean hospital stay lasted for 2 days, with a range of 1-20. The worst affected patient remained on artificial intubation for 15 days. The onset of the earliest neurological symptoms took 30 minutes to 7 hours.

Bungarus fasciatus activates almost the moment darkness falls. They appear in various habitats, but they require one substance – water.

This isn’t a semi-aquatic snake like the rice paddy snake, one that swims in swamps all day and eats amphibians and fish. But banded kraits are nearly always found close to a water body. Their favourite spots include by water channels on the edges of rice fields, in the moist grass next to ponds, and on the borders of wet forests. Shallow streams beds are another possibility. Unlike the Russell’s viper, it’s rare to find them in the centre of agricultural fields like rice paddies, as they much prefer the borders.

Their love of water means that wet season is their most active period. Formerly dry fields and village roads may be inundated with water sloshing around, which opens up a whole new tantalising landscape for banded kraits to feel comfortable in. Sometimes this rainfall goes too far, and flooding forces them to seek dry land inside village houses. 

During daylight hours, Bungarus fasciatus even sets up base in drains. This species appears to be sluggish at first glance, moving slowly around the edge of a pond. But this is more efficiency than being a tired snake. Banded kraits save their energy and unleash it all at once when they need to break free from a grip, or lurch their upper body towards the hand gripping the tail, while biting all at once.

Banded kraits have also been witnessed to judder and vibrate their body during daylight when people stray too close. This is theorised to be a warning of some kind, perhaps one that their natural predators are more attuned to than human beings.

If picked up, they sometimes thrash wildly before resorting to biting, to generously give people a brief final warning. Despite the danger, you’ll occasionally find overconfident snake handlers showing banded kraits off in Bangkok bars.

Banded kraits have long been known as a fellow snake eater, and the list of confirmed snake species is long. A 1994 report combined all previous diet records of Bungarus fasciatus with results from banded kraits dissected by the author. The result was that 80% contained snake prey in their stomachs. Other meals included 2 eggs, one lizard and one fish, with zero mammals.

Unlike a cobra, Bungarus fasciatus relies more heavily on its sense of smell to hunt than its eyesight. One story involved a fully blind banded krait owned by a Mr. Y. Siah in Bangkok. Despite lacking all visual information, this krait was still able to locate and swallow snake meals placed within its terrarium.

Sometimes, Bungarus fasciatus tastes its own medicine. The other main ophiophagous (snake-eating) snake in southeast Asia is the king cobra, and banded kraits are one of their confirmed prey. Banded kraits are also a necro snake. In Assam state, India, one was spotted eating a decomposing snake, already dead, which was gruesomely confirmed by the presence of maggots.

The banded krait’s confirmed meals include…

Sunbeam snake – this iridescent, rainbow-tinged snake appears in almost identical habitats to banded kraits: waterways near rice fields and the grassy edges of ponds. They also become more common after rainfall, so it’s not surprising that banded kraits are confirmed to eat them. A harmless species.

Buff-striped keelback – a similar story. This is a harmless common snake, which constantly appears by ponds and shallow waterways, without actually being an aquatic snake. Banded kraits grab any species which happens to be nearby.

Tonkin pitviper – banded kraits can swallow fellow venomous snakes, as witnessed in Vietnam in 2017. By a small stream, a banded krait swallowed a Tonkin pitviper (Ovophis tonkinensis) which it had already ruthlessly dispatched. The prey’s body was covered in such grisly bite wounds that eggs within its body were exposed.

Wall’s krait/lesser black krait – both fellow members of the Bungarus family, and with a lethal neurotoxic venom, which banded kraits are clearly resistant to.

The banded krait is an egg-laying species, producing 4-14 per batch. These eggs measure 2.6-3.0cm and typically hatch after 59 to 62 days. Hatchlings measure 32-34.9.cm.

Banded kraits appear at altitudes of up to 2300 metres. They also inhabit Nepal, in the foothills of the Himalaya, where it’s known as Rajasaap, or “king of snakes”.

Very occasionally, you can find black-white morphs of the banded krait. This makes them very difficult to distinguish from the Malaysian blue krait. But there’s still consistent ID signs, including a much stumpier tail for the banded krait, versus long and tapered. Banded kraits have a slightly bulkier head, making it more distinct from the body. While both have a triangular body shape when viewed in a cross section, this is even more pronounced in the banded krait. The yellow is normally so bright that it’s rare that you’ll have to use these hidden ID tricks.

As this image shows, the Asian wilds occasionally churn out a striped morph rather than banded. The colours are identical, featuring the usual vivid black and yellow.

As of 2024, banded kraits aren’t just the longest species, but have the most massive range of any Bungarus krait. They occupy a swathe of northeast India, then spread all the way to the Indonesian island of Java, covering thousands of miles. Their yellow-black appearance barely varies. But there’s a problem – according to a 2023 study, there may be 3 hidden species within this vast empire.

Using DNA testing, scientists found large gulfs in genetics, pointing to three long-separated clades: 1) Indonesia and mainland Malaysia, 2) India to Myanmar, and 3) Thailand, Cambodia, Vietnam, southern China, and peninsular Malaysia.

Within the clades, there were small genetic distances. Clade 1 had 0.4% genetic variation, based on different locations in Java. Clade 2 varied by 0.0-1.3%. But between clades, the differences were far larger, including 5.0% between clade 2 and 1, and 5.3% between clade 2 and 3.

These species aren’t officially confirmed yet, but new names have already been proposed: Bungarus insularis for Indonesia and Bungarus bifasciatus for Chinese realms. In fact, there may be up to 6 species within the banded krait. If split, the old Bungarus fasciatus name will apply to the Indian lineage.

Canada is far from a hotbed of venomous snakes, yet the country still contains three. Pacific and prairie rattlesnakes live in the west, while the only venomous snake in eastern Canada is the endangered massasauga (Sistrurus catenatus). This is the most northeasterly rattlesnake of all, inhabiting the northeast US and Ontario. They share the usual vertical pupils, cytotoxic venom, and a piercing rattle to alert intruders to their presence.

While massasaugas are classed as a rattlesnake, they don’t belong to the main Crotalus rattlesnake family with 50+ members. Instead, they’re an offshoot branch of the evolutionary tree, part of the much smaller Sistrurus family with 3 members. This also contains the pygmy rattlesnake of Florida, and the western massasauga.

This is a relatively short species at an average of just 50-70cm. The longest eastern massasauga of all time measured 100.3cm, versus 189.2cm for a timber rattlesnake. The latter is the only rattlesnake the massasauga shares territory with, as other eastern US species like eastern diamondbacks and pygmy rattlesnakes live further south (Florida, Alabama, etc).

While timber rattlesnakes prefer forests with an abundance of fallen logs and branches, the massasauga is a creature of wet areas. You’re most likely to trip over a massasauga in swampland, marshland, by the moist shores of rivers and lakes, and in wet prairies. One of their folk names is swamp rattler, another is muck rattler. They’re often found lurking in dark crayfish burrows along river shores.

This more limited habitat means that massasaugas are in sharp decline. Their range is similar to 200 years ago – New York, Michigan, Pennsylvania, Ontario, etc. But those boundaries have been badly hollowed out. Within their territory, only fragmented and isolated pockets of massasaugas remain.

Culprits include the draining of wetlands to construct housing estates, and dividing pristine habitats with roads. Massasaugas are slow and deliberate creatures rather than energetic travellers, and splitting habitat prevents individual pockets from linking up. They have a great fear of human habitat – the greatest extent is one that ventured to an Ontario golf course in 2012, directly adjacent to Blind River. Michigan is the only US state where massasaugas aren’t listed as “endangered”.

Massasaugas are one of the milder rattlesnakes of North America. Its raw venom has an LD50 score of 2.9mg, while the venom yield is similarly weak at 15-45mg per bite. An eastern diamondback can unleash a flood of 400mg per bite, and with a stronger LD50 score of 1.2mg. Timber rattlesnakes are intermediate, scoring 1.64mg with a yield per bite of 75-210mg. Eastern massasaugas also have relatively small fangs, and aren’t especially aggressive, preferring to flee into the undergrowth if possible. Unlike Mojave or tiger rattlesnakes, they lack any confirmed neurotoxic powers.

It’s estimated that no more than 3 people are bitten by massasaugas annually. The last confirmed death happened over 40 years ago. Just two deaths are known from Ontario.

Massasaugas are recognisable by eyemask or hourglass-shaped blotches, which are the densest black. On its flanks, the blotches are smaller, but just as tightly packed and vividly black. Overall, they have a blacker appearance than the timber rattlesnake from a distance.

In Canada, massasaugas are active only from late April to October, due to cooler climates. While massasaugas aren’t especially energetic, their daily movements can pile up over the course of a year. One male massasauga travelled 4000 metres from the scientists’ initial capture point to its winter hibernation site. It’s been observed that massasaugas are more commonly found hunting where tree canopy cover is below 50%, and ground vegetation cover is above 60%.

Like timber rattlesnakes, massasaugas often hibernate communally. Up to ten have been found together in vacant crayfish or mammal burrows. Other sites include twisting root beds and rock fissures. These hibernation dens must be below the frost line, or the sheltering massasauga may freeze solid.

Instead of machinegunning baby vipers out every year, massasaugas reproduce relatively slowly. In Ontario, they produce biannually, and some mothers only triennially. Batches of fresh massasaugas typically contain 3-20. Newborns are 18-25.6cm long.

Massasauga venom is confirmed to transform with age. A 2022 study tested equal quantities of venom from Sistrurus catenatus of various ages: juvenile, subadult, and adult. The results clearly showed that juvenile venom had stronger haemorrhaging and proteolytic powers, but was less lethal.

They tested the minimum haemorrhagic dose (MHD), the lowest quantity of venom required to cause a haemorrhagic zone 10mm in diameter. The lower the score, the more powerful the venom. Juveniles achieved an MHD of 2.39 µg, versus 3.72µg for subadults and 4.52µg for adults. It was theorised that the haemorrhaging allows pre-digestion of prey, when their mouths can’t gape as widely.

Meanwhile, juvenile venom had an LD50 score of 2.5µg/g, measuring the quantity required to kill 50% of prey injected. Sub-adults were far lower at 0.81µg/g, while adults were the lowest at 0.7µg/g. As massasaugas age, their venom sheds any unnecessary trivialities and becomes a focussed elixir of assassination.

One detailed case study came from Ontario in 2018. A 25 year old man was wandering the east Georgia Bay, making the mistake of wearing sandals, when a hidden massasauga sank its fangs into his big toe. Symptoms rapidly appeared including a visibly swollen lower leg, and a haemorrhagic zone around the toe. He also had a nasty bruise (hematoma) near his groin, well away from the bite site, which covered 6-12cm. The man resisted visiting hospital until 22 hours post bite, when he finally gave in. 

Blood testing revealed massive disruption of important clotting factors. The man’s fibrinogen was severely suppressed, at 0.6µmol/L versus a healthy range of 5.1-11.8. His partial thromboplastin time soared to 180 seconds, versus a standard range of 20-40s. Thromboplastin accelerates factor Xa, which itself accelerates the conversion of prothrombin to the clotting material thrombin.

The man rapidly received 10 vials of antivenom. Later, when his swelling and coagulopathy still hadn’t healed, he was given an extra 10 vials. All the blood markers suggested that spontaneous bleeding was imminent. Yet the patient experienced no haemorrhaging at all, possibly due to receiving 32 vials of antivenom over his hospital stay. At 40 hours post bite, the swelling had largely subsided. The man was discharged after 4 days, with no lasting effects.

Sistrurus catenatus bites are easily survivable if you reach the emergency room rapidly, or even if you don’t. Other cases are very similar to the one above. A 62 year old man was bitten by a massasauga on the right thumb, causing his fibrinogen levels to plummet to 1.47 µmol/L, yet he experienced no excessive bleeding.

Another case happened in Frederic, Michigan, when children found a 30cm massasauga under a kayak at a campsite. A 56 year old man appeared and placed the massasauga in a coffee can using a stick. While showing off his prize to campsite residents, he was bitten on the left thumb. By 24 hours post bite, his hand was fully swollen, but there was no mention of haemorrhaging. Bruising spread all the way up his forearm by 96 hours. The man ultimately received 4 antivenom vials, and survived with ease, but experienced a feverish reaction to the antivenom serum.

The massasauga’s symptoms are fairly consistent: plenty of swelling and bruising, but little haemorrhaging or death (in humans anyway).

The diet of the massasauga is well researched and the truth is clear: this snake is overwhelmingly a mammal hunter. Luckily, this tends to be small scurrying mammals rather than strange ape creatures that got lost and wandered out of Africa.

Firstly, we have a 2009 study, which combined samples from both Ohio and Ontario. In Ohio, mammals contributed 97.6% of the diet. In Ontario, mammals contributed 88%, as two snakes were also recorded. The most popular prey was identical between both populations: the northern short-tailed shrew (Blarina brevicauda). Massasaugas may be opportunistic based on location, but this is the meal they go to bed dreaming about each night. One surprising prey was the eastern chipmunk. Another study found an American red squirrel.

The second study was conducted in 2023, across 10 different massasauga populations in Michigan. Again, mammals utterly dominated. This time, northern short-tailed shrews were second most common, tied with masked shrews. The most popular prey was easily the meadow vole (Microtus pennsylvanicus). No massasaugas with a grotesque dog walker-shaped bulge were found. The study concluded that “small mammals are a crucial part of eastern massasauga rattlesnake diet“.

Snakes are occasionally chanced upon and gobbled up by the massasauga as well. Ther confirmed prey include…

Common garter snake – an ultra common species of rivers and marshes, Found in 47 of 48 lower US states. Slightly venomous.

Dekay’s brown snake – a harmless snake averaging at less than 30cm. Hides in well vegetated areas. Also confirmed prey for speckled kingsnakes.

Eastern massasauga – cannibalism was confirmed for this snake in a study conducted in southern Michigan.

Northern redbelly snake – part of the same Storeria family as Dekay’s brown snakes. Another harmless, shy snake that lurks under logs or rocks. Also confirmed prey for copperheads.

Smooth green snake – the king of camouflage. Harmless. Mainly inhabits moist grassy areas.

Feeding on snakes is very rare for a rattlesnake. The one species where they contribute a decent portion of calories is the Querétaro dusky rattlesnake of Mexico. Then again, massasaugas aren’t part of the main Crotalus family, and this one area where maybe they’re diverging. They’re also rumoured to feed on more amphibians than the average rattlesnake. This 2023 study found three records: two unidentified frogs and toads, and a red-backed salamander.

Massasaugas target their preferred prey, as the venom was proven in a 2008 study to be more lethal to mammals than lizards and frogs. Younglings also wield the dark art of caudal luring. Their rattle and lower tail is a bright sulphur yellow, which tricks local frogs into thinking they’ve found a tasty insect meal. A 1984 study on captive massasaugas observed them wiggle the tail in a mesmerising motion. The frogs drew closer in excitement, and bit down on the tail, which provided a signal for the massasaugas to turn around and eat them. In adulthood, this bright tail tip fades away.

In 2011, the massasauga was split into two species: the eastern massasauga (Sistrurus catenatus), which we’re talking about today, and the western massasauga (Sistrurus tergeminus). The latter is similar in its lifestyle and inhabits Texas, Oklahoma and Kansas, appearing only west of the Mississippi river. There’s also a subspecies of the western form called the desert massasauga (Sistrurus t. edwardsii).

According to one of the studies above, eastern massasaugas have the most mammal-dominant diet. Western massasaugas eat mammals with secondary helping of lizards, whereas desert massasaugas reverse this, with lizards first and mammals second, which makes sense in arid landscapes.

The most common spitting cobra in Africa, with Nigeria the busiest spot of all. This nightmarish creature combines the ability to spit venom 57 times in 20 minutes, with the usual venom injected rapidly during a bite. Black-necked spitting cobras measure 1.2-2.2 metres, and are a rare snake which humanity has made more common rather than less. Their natural habitat is open areas rather than forests, and with heavy deforestation progressing annually in Nigeria, they’ve moved into these open areas and begun to terrorise farmers. Forest cobras are the opposite, shunning human civilisation (and are therefore declining).

The black-necked sitting cobra aims directly for eyes. A successful hit will blind you for 3 days, causing your eyeball to go numb. Its bite isn’t to be underestimated either. Naja nigricollis has highly anticoagulant venom which cleaves directly through fibrinogen and cross-linked fibrin, the final clotting material of wounds. The venom also targets the heart. When injected into mice, swelling appeared on their heart tissue, and collagen protein fibres degraded. Their heart tissue even changed colour, from deep red to paler.

Naja nigricollis is most likely to prowl the Nigerian countryside during wet season (June-July), whereas they become more sluggish during dry season (December-February). They also eat significantly less during dry season. As younglings, their primary food source is the lizard, Agama agama. Adults graduate to birds and small, scurrying mammals.

The Grayia genus of African watersnakes has 4 members, and Smith’s watersnake is easily the most common. This is a non-venomous snake of swampy forests, particularly swamps in forests of dense undergrowth, covered with shrubs and ferns. Smith’s watersnakes are semi-aquatic, and can be extremely common in certain swamps, where they prey exclusively on fish and amphibians. But you don’t have to worry about slipping and landing on your back in the mud. Smith’s watersnake wouldn’t dream of hurting anybody, and would be unable to if a murderous urge suddenly struck.

This Nigerian snake reaches a maximum of 160cm, yet is low on the food chain. Grayia smythii’s many predators include herons, scooping them out of the water with their long beaks, human fishermen, Nile monitors, and possibly forest cobras and black-necked spitting cobras.

This is a very common species, ranging from Uganda in the far east to Gambia in the far west. Smith’s watersnake lays 8-14 eggs, which are well hidden in buttress roots, buried beneath leaf litter. In a 2001 study conducted 15km from Port Harcourt, Nigeria, fish constituted 25% of their diet, and amphibians 75%. Their single top prey was the western clawed frog (Xenopus tropicalis).

A common Nigerian snake with a moderately dangerous venom, which mainly causes swelling, fever, and pain. The spotted night adder (Causus maculatus) is one of the Africa’s most adaptive venomous snakes. They appear in a huge range of habitats, from dense rainforest to open savannahs to canyons in Ethiopia. They’re spread far and wide, from Uganda to Nigeria to Sierra Leone. They only avoid true deserts, requiring some moisture, as their main food source is amphibians.

Spotted night adders are easily recognisable. They have an olive base, overlaid with widely spaced black dots. A few are missing these black dots, but there’s little variation in colour with Causus maculatus. This is a small snake at 30-60cm, maximum 70cm, and males take part in ritualistic wrestling.

According to a 2004 study, conducted in a rainforest patch along a river shore in Nigeria’s Akwa Ibom state, spotted night adders eat 66.7% amphibians and 33.3% small mammals. Confirmed species include Hallowell’s toads, square-marked toads, and golden puddle frogs. Spotted night adders have natural resistance to heart-stopping bufotoxins produced in these toads’ slimy skins.

The most popular pet python worldwide. The ball python is relatively short, typically measuring 1 metre, with an all time record of 183cm. This is both the most northerly and western python worldwide, excluding invasive species. Ball pythons range from Gambia to Uganda, and Nigeria lies at the epicentre. Many Nigerians worship this python; the Igbo people build coffins and conduct funerals for ball pythons whenever they die.

Ball pythons prey on birds and mammals. Females tend to live in burrows, while males have tree-climbing tendencies. Their name originates from their famous instinct to coil into a ball when threatened by predators. It’s estimated that 100,000 ball pythons are exported from Africa annually for the pet trade.

Ball pythons lay just 10 eggs per clutch, but the eggs are relatively large at 6.0 by 4.0cm. The main purpose of their infamous ball is protecting their brains, but a 2004 study from Lomé, Togo revealed how mothers use it to protect offspring. It found that if mothers coiled around their egg clutch, the temperature was only slightly increased, but it significantly prevented evaporative water loss. Offspring of these “balled” eggs were larger, faster swimmers, more energetic, and grew more rapidly, compared to eggs that mothers didn’t coil around.

A large Nigerian snake which regularly breaks through the 2 metre barrier. This is a tree-climbing snake which is proven to reach 25 metres above ground. Blanding’s catsnake (Toxicodryas blandingii) is a nocturnal species which is active from dusk till dawn, and has a moderately dangerous venom. In one of the few cases on record, the victim suffered from cramps, random sensitiveness, and random aches and pains, and recovered within 2 days.

This Nigerian snake requires trees, but is comfortable in tree clumps directly next to human habitation, meaning that they’re not close to endangered. Its diet is varied, including dwarf chameleons and more mammals as adults, including bats such as golden short-palated fruit bats and Angolan free-tailed bats. They seem to be especially amazing climbers. In 2010, one Blanding’s catsnake managed to grab some prey caught in a large bat net, which was erected in a forest by incredibly thin wire. It must have climbed the mesh or the thin wire itself to acquire the bat, which was 2 metres above ground.

Blanding’s catsnake belongs to the same family as the powdered catsnake (T. pulverulenta), but is easily the longer of the two, reaching 2.8 metres versus 1.25 metres.

This potentially deadly venom bomb belongs to the same Echis genus as the infamous saw-scaled viper of India. Roman’s carpet viper is a very recent addition, as it was only made an official species in 2018, when it was split from the West African carpet viper. It was distinguished by an especially high count of ventral (belly) scales, with 150-168 in females, and 146-156 in males. The number of scales around the eyes was also higher.

So far, the largest known Roman’s carpet viper is a male measuring 71.5cm, found in Central African Republic. In the initial 2018 discovery study, the largest male measured 61.5cm and the largest female 55.5cm.

Roman’s carpet vipers are found mainly in central and northeast Nigeria, and while research is scarce, they deal out plenty of bites. A study on antivenom effectiveness gathered hospital data from 2021 and 2022 in Nigerian hospitals, and managed to find 5467 Echis romani victims. Its symptoms include coagulopathy, AKA blood clotting chaos, and the antivenom was indeed effective, causing a 93-94% reduction in mortality.

A species of drier areas, which is most common in northern Nigeria. The Saharan sand boa (Eryx muelleri) lives not in majestic sand dunes, but dry savannah. Occasionally they appear at the transition zone between desert and dry savannahs, but never within sand deserts like the Arabian sand boa.

Saharan sand boas are completely harmless and rarely exceed 80cm. Within dry savannahs, they most commonly lurk in well vegetated spots rather than bare soil, possibly for disguise, or possibly because prey is more common amid tangled bushes and dry grass. Eryx muelleri eats a mixture of lizards and mammals, shifting further towards mammals with age, as their mouths are simply too small early in life. The African five-lined skink is one confirmed reptile meal.

This species has a small presence in the international pet market. Between 2007 and 2012, 571 were exported from Togo, a fraction of the relentless conveyor belt of ball pythons. The Saharan sand boa species has virtually no variation in its appearance, being virtually identical across its central African range.

The other main Echis viper in Nigeria. The West African carpet viper (Echis ocellatus) was said in 2001 to account for 66% of venomous snakebites in Nigeria. Now that Roman’s carpet viper has been made an independent species, that proportion will be reduced, but it’s still perhaps western Africa’s most dangerous serpent, alongside the black-necked spitting cobra.

This snake is most common in western Nigeria, while Roman’s carpet viper inhabits the east. West African carpet vipers reach a maximum of just 65cm. There’s few neurotoxic symptoms like paralysis and respiratory failure, but Echis ocellatus doubles down on every other dark power: swelling, tissue necrosis, sudden haemorrhaging. In Ghana to the west, Echis occellatus causes 60% of snakebites, and 90% of deaths. The mortality rates of bites have been reported at 11-17%.

When preparing to attack, the West African carpet viper rubs its jagged scales together to create its signature “sawing” sound. This species derives a large portion of its diet from arthropods like scorpions, though less than the Indian saw-scaled viper. This risky diet probably explains why its venom became so lethal, compared to the spotted night adder, which doesn’t need to disable its amphibian prey as rapidly.

A pale, thin snake which reaches a confirmed maximum of 1.58 metres. The western rufous beaked snake is common in Nigeria and tends to inhabit dry and moist savannah, open woodlands and grasslands. Areas with bushes and thickets are a haven for this snake. They move by day, and travel relatively slowly, regularly taking shelter in termite mounds and animal burrows. Rhamphiophis oxyrhynchus has virtually no patterns, neither from a distance nor up close.

Rufous beaked snakes are rear-fanged and must chew their victim repeatedly to inject venom. One detailed report comes from a 2014 article, when a Rhamphiophis oxyrhynchus snapped down on a 24 year old man’s finger and maintained a tight grip for 20 seconds. Within 20 minutes the finger began to swell. Within hours, this covered the entire forearm, and soon the victim struggled to move his arm. But by the next day, these symptoms had faded except for a mild, generalised pain in his arm.

Rufous-beaked snake venom also contains neurotoxins, specifically the unique rufoxin, but these have yet to manifest in human beings. The only risk is the incredibly tight grip when they snap their fangs shut, and a benevolent determination not to hurt the snake by ripping its mouth off.

A snake of swampy rainforest which sticks to the forest floor rather than climbing trees. Mehelya is a weird family, as it has large spaces between its scales, revealing the pale skin below. Yet the individual scales are sharp and jagged, hence the “file” name. They also have a triangular shape when viewed in a cross section.

As for this species, the western forest file snake (Mehelya poensis) is common in central Africa, and Nigeria lies roughly at the epicentre of its range. Mehelya poensis eats a variety of reptiles; lizards, geckos and fellow snakes are all parts of its bewilderingly large menu, as are toads in the Bufo family.

Mehelya poensis has a bizarrely shaped snout, which is shaped like a spade. This is optimal for shifting aside loose soil. Swampy forests of Nigeria are home to a menagerie of snakes, but while Smith’s watersnakes stick to swamps themselves, this species specialises in invading burrows, shifting aside loose debris to enlarge a path. Western forest file snakes are no threat to humans, rarely biting even if picked up. This is one of 5 Mehelya filesnake species in Africa.

The Boiga catsnake family has 42 members, mainly found in the Indian subcontinent and southeastern Asia. Their signature characteristics are vertical slits for pupils, resting on branches for most of the day, and a rear-fanged venom traditionally viewed as mild, which nevertheless contains a smattering of neurotoxins.

The green catsnake (Boiga cyanea) is the most common of the family in Thailand, and perhaps the most common overall. They cover Vietnam, Cambodia, Myanmar, and to the northwest, they reach Bangladesh and fizzle out in northeast India. To the south, they just cross the southern Thai border into peninsular Malaysia.

Green catsnakes typically rest on branches 2-3 metres high, never exceeding 10 metres. By day, they rest immobile, while by night, they activate, and move up to 55 metres in a session. This is an energetic snake, unlike their dangerous Thai lookalike, the white-lipped pitviper. Green catsnakes are a notorious bird predator, contributing 33% of nest raidings in northeast Thailand. Their most common prey includes the oriental garden lizard, and they don’t shy away from fellow snakes like striped kukri snakes.

The green catsnake has never once killed a human, but a brief bite is capable of killing fellow snakes within 30 hours.

Australia’s only Boiga catsnake species. This is a notorious invasive species which landed on the US Pacific territory of Guam just after World War 2, and proceeded to decimate the island’s native bird population. Brown tree snakes also inhabit New Guinea and the Indonesian island of Sulawesi.

This species never has any traces of green or blue on its body. It’s significantly longer than the green catsnake, at an alltime record of 3 metres (recorded on Guam) versus 184cm. Its venom is typical: weak with a handful of neurotoxins. A 2006 study identified 446 bites over 18 years on Guam. No deaths occurred, and only infants under 1 year suffered systemic effects. Disturbingly, many bites happened in victims’ bedrooms. Parents walked in to find a brown tree snake coiled around their child. This species loves to slither stealthily through people’s windows.

All Boiga catsnakes are strong climbers, but the brown catsnake ascends above to become perhaps the greatest climber of all 3900 snake species. In 2021, they were discovered to use a unique “lasso” manoeuvre, coiling a small portion of their body around a metal cylinder for grip, then thrusting the next two thirds of their body upwards. This allowed them to climb a metal cylinder which scientists had placed a bird box on top of, which was so smooth that scientists believed it to be impenetrable.

This species lives exclusively on the island nation of Sri Lanka, just southeast of India. Though superficially similar to the brown tree snake, it is overlaid with black (or chocolatey brown) bars and stripes. Sri Lankan catsnakes have a vicious disposition, and will unleash a furious storm of painful bites if gripped.

This species is relatively short, as the maximum so far measured just 120cm, though Guam has far more researchers due to being a US military base. Confirmed prey include geckos, which it often invades houses to snatch. The Sri Lankan catsnake is also a confirmed cannibal.

Despite their savage aggression, Sri Lankan catsnakes are unable to kill humans, no matter how much they scheme and plan. A 1969 report detailed a man who was bitten on the left middle finger for several minutes. His hand later swelled to levels similar to a bee sting, but subsided after two hours. He experienced no systemic symptoms. Likewise, a 2023 study detailed 7 bites from 3 Sri Lankan catsnakes, including Boiga ceylonensis. None led to systemic symptoms, just mild local symptoms. Sri Lanka catsnakes are recognisable by a consistent black streak that starts behind the eye.

The most westerly and the most northerly of the 42 catsnake species. Common catsnakes (Boiga trigonata) are the Indian version, just as the green catsnake is the Thai version. They cover virtually the entire country, as well as Sri Lanka. To the west, they also reach Pakistan, pushing past any of their family. To the north, they’ve been sighted near Islamabad.

The common catsnake has more viperid patterns than other Boiga catsnakes, and is believed to be mimicking the Indian saw-scaled viper, gaining it a shield of protection. This is one of the most ground-dwelling catsnakes, appearing in low bushes as well as tree branches. Boiga trigonata is a confirmed meal for birds of prey like Jerdon’s baza, and fellow snakes like the infamous banded krait (Bungarus fasciatus).

Like all Boiga catsnakes, they lay eggs rather than live young, in batches of 6-12. Common catsnakes have a varied diet, but are confirmed to feed on oriental garden lizards (Calotes versicolor), like the green catsnake in Thailand. This seems to be a beloved meal of the Boiga catsnake family overall.

This catsnake species lives exclusively on the Andaman Islands, officially part of India, but closer to Thailand geographically. The Andaman catsnake was originally assigned as a Sri Lankan catsnake subspecies, but is now independent. This catsnake is rarely found outside of forests, particularly inhabiting tropical moist deciduous and tropical evergreen forest. They sometimes appear in the thatched roofs of houses, and are near exclusively nocturnal.

This is a species which transforms with age. At birth they’re a bright orange, even a vibrant red, which spreads to their eyes. In adulthood, they blossom into a dull olive-green, like a reverse butterfly.

The Andaman catsnake is mid-length for its family, at an all time record of 167cm. Andaman catsnakes move slowly and patiently, prowling around their forests with no need to rush. But if flustered, they’ll suddenly fly into an elaborate display of aggression, with their body coiled into an S, their tail wiggling, and unleashing multiple mock strikes. Andaman catsnakes are rear-fanged like other Boiga members, but nothing is known about venom’s chemical makeup or potency. Their diet consists of lizards and geckos.

This species has no overlap with brown tree snakes or green catsnakes, because it lives exclusively in the Philippines. Philippine catsnakes (Boiga philippina) can reach a relatively long 213cm, and supposedly have a stronger venom than other members, though research is severely lacking.

This snake makes a loud puffing noise before unleashing its strike, usually from its tree branch. Philippine catsnakes have a tendency to show up in trees near chicken coops, having just returned from a ground mission to snatch the eggs.

Philippine catsnakes have some of the least obvious patterns. From a distance, they’re a plain colour, usually orange or light brown. Thin, faint bars appear when you get closer, but no complex viperid patterns like the Indian catsnake. Another catsnake of the Philippines is Boiga angulata, the Leyte cat snake, and this has far more complex patterns, making the two easy to distinguish.

This species is an expert at coiling its long body sinuously around stalks and branches, to avoid a hard plummet to the ground. It does this instinctively, with no need for conscious thought (not like it’s capable of thinking anyway).

This species is endemic just to three islands: Great Nicobar, Little Nicobar and Pilo Milo Island. The Nicobar catsnake (Boiga wallachi) reaches a maximum of 1.4 metres.

This snake is poorly researched, and we mostly have anecdotal reports from locals to rely on. According to this scribe, the Nicobar catsnake is highly terrestrial (ground-dwelling), and perhaps one of the least reliant on branches. Many were found on the forest floor by small forest steams, hunting for frogs. Amphibians are also a rare diet for Boiga catsnakes, which rely primarily on reptiles and birds. They tend to appear alongside triangle keelbacks, and rumours suggest its venom is unusually strong. One local man reported a swollen leg persisting for 2 days. Another blamed the Nicobar catsnake for his amputated thumb. The venom’s chemical composition hasn’t been analysed yet.

Nicobar catsnakes hunt birds as well, as they stealthily invade chicken coops. This is a mainly yellow catsnake, but adorned with subtle black markings on each scale.

This Boiga catsnake lives in one specific region of India; the western Ghats mountain range, a damp range of forested hills in the southwest which is officially a Unesco World Heritage site, on account of being a biodiversity haven. 

Thackery’s catsnake was discovered in 2019, and has one of the weirdest diets. It feeds on frog eggs, specifically those of the Bombay night frog (Nyctibatrachus humayuni), a species endemic to the western Ghats which lays its spawn on branches overhanging small streams. This is a perfectly placed meal for the arboreal Thackeray’s catsnake. This is the first Boiga catsnake among 42 to be a confirmed frog egg predator.

In the original discovery, all Boiga thackerayi individuals were found in trees near forest streams, and were active at night. When one was placed in captivity, it refused all attempts to feed it ground frogs, but happily accepted climbing frogs like the Indirana family.

Thackeray’s catsnake is believed to be closely related to the Sri Lankan catsnake. They measure 55-120cm and share the patterns of an orange-brown base overlaid with black. This was the first new catsnake to be discovered in the Western Ghats for 125 years.

The green-headed catsnake (Boiga bengkuluensis) is a species of southern Thailand and peninsular Malaysia, which reaches 167cm, and has a completely unresearched venom. This snake embraces the branch lifestyle all the way. It’s particularly common in tropical lowland forests packed with dense thickets, and you’re likely to meet them during a heavy rainstorm.

This is a mainly green member, but couldn’t be more different from the neon green catsnake. This species is a dark, slimy green, like the essence of swamp, or moss growing on an old rainforest boulder. Even their eyes aren’t safe from these jungle shades. These eyes are especially bulging and have the usual vertical slits.

The green-headed catsnake was originally discovered in Sumatra in 2003, when scientists separated it from Boiga drapiezii umbrella. Then came a debate over whether Boiga bengkuluensis inhabited southern Thailand, as some considered the sightings to be unusual green catsnake morphs. But a 2021 report confirmed their presence there, as well as in peninsular Malaysia.

Probably the second most abundant Boiga catsnake in Thailand. This species also covers Cambodia, Vietnam, Myanmar, and is especially common in Hong Kong. Like the green catsnake, their range fizzles out in Bangladesh and far northeast India.

This ticks most of the boxes for a Boiga catsnake: sharply vertical pupils, a branch-dwelling lifstyle, and a mild venom which has never killed a human on record. The many-spotted catsnake averages at 70cm, yet certain individuals can break far beyond this to reach 187cm. They lay 4-8 eggs and feed on lizards and birds. Their personality is a two-sided coin. Firstly, they’re calm and take much provocation to enter aggressive mode. But when they do, they readily strike and snap at intruders until they back off in fear. Many-spotted catsnakes are reasonably flexible, appearing in forests, woodlands, gardens, bamboo groves and cultivated areas. The one rule is that they always require trees.

In 2023, this species gained even more territory. The tawny catsnake (Boiga ochracea) was subjected to genetic analysis and found to have low differentiation to many-spotted catsnakes. The two were combined, and Boiga multomaculata extended its empire north-westwards into Bangladesh. Boiga ochracea ceased to exist overnight, at the scribbling of a scientist’s pen.

A rainforest snake, also found in clearings next to rainforests, with immensely variable patterns. This is a green-black snake measuring 40-80cm, with neon blue cracks between its scales, which enlarge as they inflate their throats in anger. Philothamnus carinatus cover most of the Congo rainforest region: DRC, Congo, Gabon, and just reach far western Uganda. They also have an island population on Bioko in Equatorial Guinea.

This Congo snake undergoes a great shift with age. As juveniles, they’re a dull brown, and spend their time rummaging around in leaf litter on the rainforest floor. Into adulthood, both their colour and lifestyle transform; they become green with many blue and black shades, and ascend to the high tree branches.

Supposedly, Philothamnus carinatus varies wildly in abundance. In one forest, they’re the most common snake, and in the next forest, they’re nowhere to be found. Their diet is a mystery, and likely contains frogs, similarly to other Philothamnus members. Their confirmed predators include the bird snake (Thelorotnis kirtlandii), a fellow tree branch snake, which is found lower on this list.

A venomous viper which primarily clings to tree branches, and moves only by night, with the savagely vertical pupils to prove it. Atheris squamigera stretches from Cameroon in the west, through the Congo rainforest, to southwest Kenya in the far east. This is a highly likely snake to stare at you menacingly from a jungled rivershore, while your boat sails uneasily down the Congo river.

Atheris squamigera is a fairly short, though thick snake. In a 2000 study, the maximum male length recorded was 67.0cm, and the maximum female length 70.5cm. Most of their diet consisted of mammals, particularly shrews in juveniles, and rodents in adults. African bush vipers regularly remain on the same branch for 48 hours, and they mainly appear in lowland rainforests at altitudes of 100-400m. Atheris squamigera loves forests with the densest, most tangled vegetation, amid rainfall totals of up to 10,000mm annually.

This snake has immense colour variety, from standard green to orange to turquoise. It’s possible that these morphs correlate to certain areas of rainforest, or that they’re totally random.

While not to be underestimated, bites by Atheris squamigera are rarely fatal. A 26 year old man was bitten twice on the foot by his pet in a 2022 report. He suffered minor sensitivity and swelling, and a reduced fibrinogen count of 121, below the healthy range of 180-500 mg/dL. But there’s also reports of a Central African Republic victim who died within 6 days, despite blood transfusions and antivenom infusions. This is a branch-clinging snake, but may block vehicles on roads occasionally.

A very indistinct snake, which is black and shiny like many of its neighbours, sometimes with a pale neck collar. The western forest centipede eater (Aparallactus modestus) reaches a maximum of 64.5cm, but is typically 35cm. Forest floors are their domain, in dense primary and secondary rainforest, and they range from Uganda through Congo and DRC to Equatorial Guinea.

Western forest centipede eaters rarely appear near human habitation, but they do appear in thick plantations on the edges of forests. Only a few details are available for this species. A 1966 report mentioned a juvenile Aparallactus modestus coughing up 100 termites. This species is hiding behind a false name, as while the 11-member Aparallactus family does hunt centipedes as a whole, this is a rare species to eat earthworms instead. It possibly wants the local earthworms to know this false name and get complacent.

The difference is evident in its fangs. Other Aparallactus members have a rear fanged venom, designed to subdue dangerous centipedes. But Aparallactus modestus lacks the grooves in its rear fangs which the venom flows down. It’s therefore assumed to have a less developed venom system, as its prey is far less dangerous.

The cobra in Africa most restricted to rainforests. This is so different to other African cobras that along with Christi’s water cobra, it was once placed in the separate genus of Boulengerina. This species inhabits rivers within rainforests, as well as the vegetated shorelines. Banded water cobras (Naja annulata) have a heavily neurotoxic venom, and aquatic adaptions such as a thinner neck hood, reducing underwater drag. They can dive to depths of 25 metres, and easily remain submerged for 20 minutes per session.

Banded water cobras tend to flee rapidly if confronted by humans, escaping to the water where it feels comfortable. They lay 22-24 eggs, and fish dominate their diet. Banded water cobras cause relatively few bites, yet are still capable of dealing out death. A 2022 newspaper report detailed a fisherman in Nyanga, the southernmost province of Gabon. A mystery snake became entangled in his fishing net and sank its fangs into his thumb. The man attempted to kill his serpent assailant with a stone, but died a few minutes later, after mentioning feeling very cold. Scientists reading the newspaper identified it as a banded water cobra, based on patterns in a still image.

Banded waters cobras average at 1.8 metres and occasionally push to 2.8m. Naja annulata is not to be confused with Naja annulifera, the snouted cobra.

A semi-aquatic snake which feeds overwhelmingly on fish, and occasionally amphibians. Ornate African watersnakes (Grayia ornata) are everywhere in the Congo region, ranging from western Uganda to Equatorial Guinea. Its habitat is essentially rivers and streams through thick forests, similarly to the banded water cobra. Its patterns are also similar: a slimy olive base contrasting vividly with thick black stripes. It’s possible that Grayia ornata is mimicking its deadly neighbour to gain a protective shield.

This species likes to hide in holes in muddy river banks, and has local names such as dibomina and moléngué. Grayia ornata is especially common in Likouala region in northern Congo. They’re so common that fishermen often scoop them up in their nets by mistake. Supposedly, otters love the taste of Grayia smithii, and will try to rip apart nets to acquire them.

Grayia ornata has a particularly long scroll of local folklore in Gabon and beyond. The locals eat this snake, believing it to taste best in dry season when it becomes fattest. Its medicinal powers apparently include improving delivery for birthing women, improving fishing and swimming abilities, treating sprains and aiding newborn babies.

Despite being heavily aquatic, Ornate African watersnakes are also spotted hanging from branches directly above streams. They reach 2-3 metres high, and plummet instantly into the water when spooked. This makes them something of a parallel to the brown watersnake of the USA.

Part of the small Gonionotophis genus, which contains just 3 snakes, all humble forest floor dwellers. If Mocquard’s African ground snake had its way, it would never emerge from its cosy forest confines. It spends most of the day comfortably ensconced in leaf litter or a hollow log, which it identified as the ultimate spot to rest in. This is a snake of primary forest or dense secondary forest. Thick vegetation on the forest floor is ideal for Gonionotophis brussauxi; hence its love for the Congo region.

This snake has a maximum length of 45cm, and an average of 30-40cm. Its scales are black, while the white visible above is actually the interstitial skin between the scales. Their diet is poorly researched, but thought to mainly consist of ground-dwelling frogs. Gonionotophis brussauxi is found in Gabon, DRC, Congo, Central African Republic, and reaches Uganda to the extreme east.

Mocquard’s African ground snakes are nocturnal, moving only under pitch black darkness. Combined with their dark colours, and the thick jungle squeezing out any faint traces of light, this snake is incredibly difficult to spot.

A harmless snake which evolved and lives in rainforests, usually close to rivers, streams and marshes. The marsh snake (Natriciteres fuliginoides) averages at just 20-30cm. It’s rare to find this snake far from water, and their diet consists of amphibians such as golden puddle frogs (Phrynobatrachus auritus).

Forest swamps are one of the best places to find Natriciteres fuliginoides. This snake is found in many countries – Gabon, Congo, DRC, Equatorial Guinea, but are rarely sighted because of their love for deep forests.

The marsh snake is excellent at thermoregulation – it’s able to maintain a consistent and optimal body temperature with very little effort. In many areas of the Congo rainforest, they coexist with their cousin, the variable marsh snake (Natriciteres variegata). A 2002 study tested whether their presence inspires heavy competition between them. It found when the two coexisted, marsh snakes were more likely to 1) eat prey from land, 2) switch to focussing on smaller prey, and 3) shift towards invertebrate prey, and away from vertebrates. It’s possible that N. variegata is a stronger hunter than this one, forcing it into niches it is less adapted to.

Dipsadoboa is a snake genus with 12 members, which aren’t necessarily rainforest-dwelling, but Laurent’s tree snake (Dipsadoboa viridis) certainly is. This species is often found on branches directly overhanging small streams within rainforests. When confronted, they kink their body into a strange shape, designed to mimic vines and foliage. If found on the forest floor, they’ll coil into a tight ball in order to hide their head. Luckily, hundreds of thousands of this species will never even meet a human, as they regularly live in the deepest regions of the Congo, such as Gabon’s Mwagna National Park.

Laurent’s tree snakes mainly feed on reptiles and amphibians, including ridged frogs (Ptychadena). They take this down using a rear-fanged venom whose effects on humans remain unknown. Rainforest swamps are another great place to find them. Lowland rainforests are their favourites and they also appear in cacao and banana plantations adjacent to rainforests, as their bushiness is sufficient for them.

Laurent’s tree snake is an egg-laying species, pumping out batches of 3-5. They average at 70-100cm, with a record of 1.24 metres. One of their relatives is the marbled snake of Mozambique (D. aulica), which appears more commonly in savannah.

One of the most abundant snakes in the Congo rainforest region. The bird snake (Thelotornis kirtlandii) is also one of the Congo rainforest’s longest snakes, at up to 1.8 metres. At birth, they measure 25-30cm.

This is a tree-dwelling snake, with the signature ability to expand their throat to bizarre levels, like a pelican about to swallow. Its venom targets blood coagulation, disrupting clotting elements and causing uncontrollable bleeding. There’s no antivenom, and one death is confirmed in an 80 year old woman, who died from kidney failure.

Bird snakes don’t instantly fly into a panic when humans approach. They often keep their cool, ignoring the intruders into their forest domain. Should you touch them, however, they’ll instantly erupt into a vicious assault.

Bird snakes lay particularly long, thin eggs, and they occasionally lay these eggs in ants’ nests. Popular prey for this snake include Ploceus weaverbirds. As well as thirteen-scaled green snakes, they’re confirmed predators of emerald snakes. A 1998 study examined a swamp in southeast Nigeria and recorded the banded-leaf toed gecko seven times as prey, as well as a rufous-winged cisticola. Reptiles and occasionally birds seems to be their menu.

A moderately sized rainforest snake which peaks at 90cm. The blackbelly snake (Hydraethiops melanogaster) inhabits the western portions of Central Africa: Congo, Gabon, Equatorial Guinea, and Central African Republic.

This is a semi-aquatic snake, which preys mainly on fish. Rainforests are its domain; you’ll never find the blackbelly snake in a small rain pool in a dry savannah. Up close, this snake has fairly complex patters. There’s a creamy stripe beginning from its eye, ending after the neck. Its body is a murky brown, but overlaid with dozens of black, diamond-shaped markings. Because these are so small, they fade away at a distance. Its head is fairly distinct from its neck (though not triangular like a viper’s), and its eyes are fairly small, with round pupils rather than vertical.

This is believed to be a non-venomous snake, though several non-venomous snakes have turned out to secrete a mild rear-fanged venom. The Hydraethiops genus has just two members, the other being the even rarer Hydraethiops laevis, also found in the Congo rainforest.

Everyone knows about the eastern brown snake or tiger snake, but Australia contains dozens of lesser known snake species, many of which are common, yet have successfully avoided the public spotlight. One is the 50cm golden-crowned snake (Cacophis squamulosus), which is abundant along the east coast, including near Brisbane and Sydney.

This shy species is fully nocturnal, and reaches a maximum of 98cm. In the wild, golden crowned snakes inhabit rainforest and wet sclerophyll forests. However, they can thrive in suburban Sydney if water sources are nearby, and are sometimes spotted crossing roads at midnight, or even dragged in by hungry cats.

This snake has an odd defensive display: it thrashes its body around wildly, while pointing its head sharply downwards. It’s theorised that this is to display the namesake light crown on its head. They also do the opposite: they rear the upper third of their body up like a cobra, with an S-shaped kink in the neck. Golden crowned snakes will make sharp strikes repeatedly, but usually with their mouth closed.

Golden crowned snakes have venom, but have never killed a human. The vast majority of their diet consists of skinks such as sunskinks (Lampropholis), and occasionally frogs, toads, and blind snakes. They completely ignore geckos, according to a 1980 study that dissected preserved museum specimens. This is an egg-laying species, producing an average of 6. Hatchlings measure 16cm.

Another east coast snake, but this time diurnal rather than nocturnal. Marsh snakes (Hemiaspis signata) are a peaceful species which often gathers together in small congregations.

Hemiaspis signata averages at 50cm, but occasionally breaks the 1 metre barrier. They inhabit marshland and wet forests, and occupy many locations in suburban Sydney, including Northbridge golf course, Cooper’s Park at Belleview Hill, and the Artarmon railway line. A pale white line from the mouth, and another from the eye, is a signature ID sign of this snake.

Its venom is incapable of killing humans; most bite reports describe local swelling. One boy developed moderately reduced fibrinogen levels and increased bloodstream fibrinogen degradation products, hinting at  coagulopathy (blood clotting disruption).

The marsh snake mainly eats skinks such as the three-toed skink (Saiphos equalis), which it immobilises with venom, then drags to a safe location (like long grass) to swallow in peace. Again, this species shuns geckos, eating them rarely, as they comprise less than 1% of its diet.

A species with a specialised diet: reptile eggs, including those of fellow snakes. The slatey grey snake (Stegonotus australis) inhabits moist forests in the far north of Australia, specifically two regions: Northern Territory and Queensland, where they’re relatively common. They reach a maximum of 130cm, and while possessing just a mild venom, they can bite humans hard if manhandled, or purposefully release an intolerable snake stench.

According to a 2009 study from Queensland, which found slatey grey snakes by repeatedly driving along rainforest roads, their favourite eggs were those of the Boyd’s forest dragon and eastern water dragon. Among snakes, they’re particularly addicted to those of common keelbacks and Lesser Sunda blind snakes. They aren’t limited to eggs, as other confirmed prey include swamplands lashtail dragons, banded tree monitors, and prickly forests skinks. They occasionally eat rats and amphibians, but the reptile world is their area of expertise.

Male slatey grey snakes are significantly longer than females. Originally, this species was dubbed Stegonotus cucullatus, but that name now only applies to those in Indonesian West Papua. Many old Australian studies are still under the S. cucullatus name.

A species primarily of mild Victoria in the far south of Australia. The white-lipped snake (Drysdalia coronoides) is one of Australia’s most cold-adapted snakes. They’re particularly common around Melbourne, and they’re one of just three snake species native to Tasmania, also including the tiger snake and lowlands copperhead. Drysdalia coronoides has even been found near the summit of Mount Kosciuszko, Australia’s highest mainland mountain at 2,228 metres.

This snake is a car tyre black contrasting vividly against a snowy white line on its lip. Their venom is confirmed to contain neurotoxins, specifically a unique post-synaptic neurotoxin named drysdalin. However, their venom yield is just 2-3mg and their fangs are especially small. No human deaths are confirmed.

A 1981 study found 61 prey of the white-lipped snake. There was just 1 mammal and 3 frogs. The overwhelming majority consisted of lizards, mainly skinks, including rainbow skinks, southern grass skinks and Spencer’s widow-eyed skinks. 6 reptiles eggs were also found.

While white-lipped snakes reach Sydney, this lies at the extreme northeast extent of its territory. Uncommonly for an Australian snake, this species produces live young (usually 3-5), although it’s been found that in colder Tasmania, females only reproduce once every 2-3 years.

A small snake of southwest Australia, including near Perth, which reaches a maximum of 46.8cm. Narophis bimaculatus prefers drier, semi-arid land: dry shrubland, coastal heaths, coastal sand dunes, and mallee woodlands. This snake requires soft soil; it’s rare to find them on hard ground like clay or granitic soils.

Black-naped snakes like to lurk under cover objects, burying themselves in soil or dried leaves. One favourite is the abandoned nests of stick ants. The instant ID sign for Narophis bimaculatus is a small black patch atop the head, followed by a larger black patch atop the lower neck. The tip of their snout is also black, as though dipped in paint.

The black-naped snake eats reptiles almost exclusively, particularly skinks such as broad-banded sand-swimmers and common dwarf skinks. They also eat legless reptiles like sedgelands worm-lizards, which are easier to suck down (legs are irritating things).

This species’ taxonomy is constantly shifting. For decades it was assigned to the Simoselaps family, then Neelaps. As of 2023, it’s the sole member of the Narophis family. Black-naped snakes overlap with the similar desert banded snake (Simoselaps bertholdi), but that species has alternating orange and black bands covering its whole body, not just the neck.

A blind snake of eastern Australia, particularly near Sydney and Brisbane. Anilios nigrescens spends the majority of its time underground in tunnels, and its eyes have gradually shrunk in response to the diminished light. This is an ant-eater, which forces the swarming colonies into its mouth using a raking manoeuvre.

The blackish blind snake is completely harmless. Its most “dangerous” weapon is a spiky tail which it pokes people with. Anilios nigrescens is one of the longer blind snakes worldwide, reaching a maximum of 80cm. However, they still fall victim to fellow Australian snakes, such as the small-eyed snake.

Blackish blind snakes are very discerning, ignoring trails of earthworms and even termites, whereas trails of worker ants readily catch their attention. Popular prey include southern meat ants and banded sugar ants. Blackish blind snakes follow these trails back to the central ant colony, where they hit the motherload of mealtimes. In a 1992 study, blackish blind snakes was able to follow scent trails that were weeks old as well as days old. However, they have some limits, as they were poor at following the trails of individual ants, rather than commonly used pathways.

A 30-45cm snake which avoids dense forests and prefers open woodland, dry grassland and arid scrub. The Australian coral snake inhabits eastern Australian, but doesn’t hug the coastline like others. It inhabits drier inland areas as well, such as gorges and dry creek beds. Australian coral snakes are identifiable by a jet black patch on the head, and then a second on the lower neck, combined with subtle white markings overlaying an orange body.

Brachyurophis australis has specialised teeth, with a serrated edge. The purpose of this is slicing its main prey, namely reptile eggs, and accessing the nutritious white and yolk within. These comprise most of its diet. They also have an adapted snout with an upturned edge, designed for digging up those leathery reptile eggs, by sifting through soil to find the hidden stashes.

The eastern shovel snout is no threat to humanity as a whole, or individual explorers lost in a dry canyon. They rarely bite even if picked up, and despite being an elapid like the tiger snake or eastern brown snake, their venom has reduced down to nothing.

The Brachyurophis genus is most closely related to the Australian Simoselaps genus. However, the two are believed to have diverged 18 million years ago. Brachyurophis likely split from the death adders and brown snakes 23 million years ago.

The black-striped snake (Cryptophis nigrostriatus) belongs to the same family as the better known small-eyed snake (C. nigrescens), which lurks under rocks and eats 95% skinks. The black-striped snake lives further north, inhabiting Queensland exclusively, rather than the east coast near Sydney. It’s easily distinguishable from its cousin, due to its orange body overlaid with a thick black vertebral stripe.

Black-banded snakes average at 50cm with a maximum of 62cm. Their habitats include woodlands and tropical sclerophyll forests, where they spend much time burrowing, often lurking in the upper 10cm of soil. Like their cousin, most of their diet is skinks. Few case studies exist, but one victim was struck 3 times in quick succession by a black-striped snake. The effects were reported as “mild”, with the victim experiencing stomach cramps and stiffness similar to arthritis near the bite site. The small-eyed snake has killed one person (in 1965), so it’s conceivable that this snake holds secret dangers.

Black-banded snakes lay live young, typically in batches of six. The stripe varies with this species. In some, it’s clearly demarcated against the orange, while in others it fades in more gradually.

A small snake which ordinarily Australians can easily walk past on their trips through woodlands. Variable black-naped snakes (Suta dwyeri) measure 25-35cm and inhabit eastern Australia, with a recognisable black head against an earthy-beige body. Suta dwyeri appears in woodlands and dry sclerophyll forests, the more lying rocks and rocky outcrops, the better.

This snake has been found on the outskirts of towns like Conargo, lurking under sheets of corrugated iron. In the wild, they hide under rocks and fallen woodland debris. This isn’t an aggressive snake, as when cornered, they prefer to coil up into a tight ball, protecting their most important body part: their brain. They also seek shelter in abandoned burrows. While their venom is mild and non-lethal, they’re capable of leaving a deposited fang in your finger.

One man was bitten on his right thumb below the knuckle. The Suta dwyeri hung on for 3-4 seconds, and 6 hours later, the man’s thumb stiffened, and the surrounding skin became sensitive to touch. The symptoms didn’t spread beyond the thumb, and they abated within days. Suta dwyeri virtually never strikes at people from a distance, but rapidly enters bite mode if picked up and manhandled.  This is another reptile-eating snake, preying on geckos and skinks.

Australia has a disproportionate amount of snakes with orange-brown bodies, followed by a black head or neck. This list alone has several, but the red-naped snake (Furina diadema) has one clear ID sign: the namesake red patch between the two black patches higher up. Red-naped snakes average at 45cm, and are especially common in suburban Brisbane. They sometimes falls into backgarden swimming pools, or are dragged through the cat-flap by feline pets. They can be found by ripping up sheet metal, assorted backyard rubbish and timber piles, or in the wild, thick beds of leaf litter, which they love to lurk in, in order to pounce on unsuspecting skinks walking past.

This snake sometimes appears in communal formation, gathering in the same spot. Scientists visited a sheet of corrugated iron in Menangle, New South Wales 14 times over 32 months, and each time they found 6-8 red-naped snakes lurking comfortably below. They’ve also been found sharing hibernation sites with yellow-faced whipsnakes.

Staying out of sight is the red-naped snake’s top priority. This is a nocturnal species which will never be found striding through a street during broad daylight, like an eastern brown snake. If frightened, they have two choices: 1) make repeated bluff strikes with their mouth closed, or 2) vanish into soil cracks. Bites are rare, though not unheard of, and their venom is mild.

A completely harmless snake which often invades gardens, resting on bushes using its light, thin body. Emerald snakes (Hapsidophrys smaragdina) are widespread in central and west Africa, ranging from Gambia, through the Congo rainforest to Uganda, which lies at the eastern extent of its range. This species measures 60-110cm, and lacks any venom that scientists know about. Its hunting strategy is to move slowly through thick vegetation, searching carefully for the bounty of lizards and frogs that lies hidden within.

While green from a distance, emerald snakes have vivid blue visible between each scale. These scales are strongly keeled to touch, though it’s highly unlikely that you’ll get close enough. H. smaragdina has a long tail for extra nimbleness in tree branches, at 33% of its body length. They also climb manmade structures like metal fences.

The Hapsidophrys genus has 3 members, just two on mainland Africa. Emerald snakes are overwhelmingly the most common, while Hapsidophrys lineatus has more detailed black patterns, and also inhabits Uganda and the Congo region, but is far more rarely sighted. The final is the Principe green snake (Hapsidophrys principis), found exclusively on the island of Principe off the coast of São Tomé.

One of the most fantastical looking vipers on Earth. This is a relative of the gaboon adder (Bitis gabonica), which has the same expert camouflage and lazy lifestyle, but takes its colours much further, like a fantastical fungi growing on a tree stump. Then there’s the savage horns sprouting above each eye, and sharply keeled body scales.

Butterfly vipers are an abundant species in Uganda, and reach a maximum of 120cm, but look larger due to their thick bodies. The English once dubbed them “river jack”, as they’re commonly found along rivers. Compared to its puff adder relative, which inflicts the most snakebite deaths in the African continent, butterfly vipers are relatively calm. Bites are few and far between. However, a captive butterfly viper inflicted one confirmed death in Dayton, Ohio in 2003.

One 30 year old keeper in Budapest was bitten by a rhinoceros viper measuring 90-100cm. He arrived at hospital within 1 hour, at which point his symptoms included moderately swollen and tense fingers, slight hypertension, slight discolouration near the bite mark, and moderate coagulopathy (blood clotting disruption). He recovered with no lasting consequences, without even taking antivenom. This keeper probably got off lightly, as butterfly vipers are capable of injecting 200mg of venom per bite. One mistake local Africans make with Bitis family vipers is applying a tourniquet, which actually compresses the venom into a certain location, allowing necrosis to worsen. 

In sub-Saharan Africa, there’s a huge group of house snakes called Boaedon with 22 members, including the cape house snake, a popular captive pet worldwide. But the Uganda house snake is a weird offshoot, which is the sole member of the Hormonotus family (Hormonotus modestus). This snake is a toffee brown colour, with vertical pupils and especially bulging eyes. While it has a large empire, spanning Guinea in the extreme west to Kenya in the extreme east, its sightings are very scattered (map).

Uganda house snakes are found on forest floors, where they prefer to lurk out of sight amidst fallen debris. They eat small mammals and lizards, and the record length so far is 87.5cm. There’s vast blank gaps in the research for the Uganda house snake, but it’s rare to find them away from forests, including the Congo rainforest and more isolated forest remnants.

This snake has few patterns, just a consistent brown, though yellow ones are occasionally spotted. A bulky head relative to the neck/body is a consistent ID sign, and a cracked pattern of scales on its head, as you can see above.

A venomous snake with a maximum length of 75.0cm, which probably won’t kill, but could leave lasting deformities. While common in certain places, Great Lakes bush vipers (Atheris nitschei) aren’t encountered often by humans, as they inhabit regions 1600-2800 metres above sea level. This viper has a narrow range, including southwest Uganda, Rwanda over the southern border, Burundi, and far eastern DRC.

Atheris nitschei begins life as a dull brown or greyish, with a bright tail tip for luring prey. In adulthood, they bloom into full jungle green shades. This is an arboreal snake which is always found in trees, tall elephant grass, or bushes, typically 1-3 metres above ground. It hunts chameleons which it scoops out of trees, small mammals and lizards.

There’s no dedicated antivenom manufactured for this viper. A 2013 report detailed a 30 year old man bitten on his left hand. Swelling rapidly kicked in, and bleeding from his gums, which lasted for 12 hours post admission to hospital. Blood analysis revealed deficiencies in fibrinogen, delayed clotting and anaemia. Another victim was bitten on the index finger, and experienced swelling spreading all the way to his chest and neck.

This snake is easily recognisable by its large eyes, and juicy green base scales overlaid with dense black lines and patterns. Large-eyed green tree snakes possess a mild venom which is likely no threat to humans, and reach a maximum of 150cm. They inhabit Uganda to the east, Angola to the south, Ghana to the west, and everywhere between, requiring areas with standing trees to survive.

Like other African tree snakes, this snake can inflate its throat to intimidate predators and make them think twice, and to particularly extreme levels. Many Rhamnophis aethiopissa have electric blue patches on their throats. Rhamnophis aethiopissa has a varied diet, but eats mammals only occasionally. Confirmed reptile prey include rainbow agamas and banded leaf-toed geckos, amphibians include forest treefrogs and Angolan reed frogs, and birds include fantail warblers and green crombecs.

Large-eyed tree snakes are able to hunt while weaving across low branches, maintaining their balance and going in for the kill. However, they don’t stick to trees exclusively, as they’re sometimes found killed on roads. At the tail, the messy black patterns change to consistent parallel stripes. Rhamnophis aethiopissa nearly always has a black stripe running through its eye, starting at the snout and ending at the neck.

The Rhamnophis snake genus contains two members, the second being the rarer Rhamnophis batesii found in Gabon and the Congo.

The green mamba and black mamba are famous because they’re two sides of the same coin. Both have a lethal neurotoxic venom, but one is green, the other black. One sticks to trees, the other rolling savannah. Inbetween, you have a less famous member of the family: Jameson’s mamba (Dendroaspis jamesonii). This is another tree-dwelling mamba, though still straying to the ground regularly. It measures 1.5-2.2 metres , and sticks to forested areas of Uganda.

Jameson’s mamba has a large range, from Nigeria to Kenya, but those in Uganda are a specific subspecies: Dendroaspis jamesoni kaimosae. This has venom twice as potent as the subspecies in western Africa (D. jamesoni jamesoni). Its bite is heavily neurotoxic, and while slightly less deadly than the black mamba, there’s a report of a child dying within 30 minutes, and other deaths within 3-4 hours. Uganda and Kenya are the hotspot of this eastern subspecies. 80% of its toxin mixture is three-finger toxins (3FTx).

The diet of Jameson’s mamba primarily consists of birds, including the red-eyed dove, and mammals, including Zenker’s fruit bat. Younglings occasionally eat lizards and amphibians, but at over 100cm, warm-blooded prey fully takes over. Jameson’s mamba has a strong bias towards arboreal (tree-dwelling) meals. While green overall, you can recognise Jameson’s mamba by a darker tail of oil spill blue.

A quiet snake found only in forests, which averages at 40-70cm. The collared snake-eater has small black eyes, and a maximum length of 86cm. Its believed that blind snakes are its sole prey, particularly those of the Typhlops family.

Collared snake-eaters (Plemon collaris) have an extremely short tail, at just 4-5% of its total length. This tapers into a spike, likely for poking predators in self defence. Its body is almost completely black, until the neck begins. This contrasts against a pale white belly, which usually has no patterns.

Polemon collaris has shiny scales which are smooth to touch. Its head is indistinctive form its neck, carrying on like a tube.This is a fairly widespread snake, inhabiting Uganda, Zambia and the Congo alike, anywhere an abundance of tropical and subtropical rainforest remains standing. But they’re seen relatively rarely, due to their shyness and love for rummaging around in forest leaf litter all day. They’re likely more abundant than anyone realises. This slow-moving snake is nocturnal, and is usually found below 1200 metres.

Part of the 4 member Toxicodryas family, which all cling to branches for most of the 24 hour day, and most of the 12 month year. This slightly venomous species ranges from Niger in the far west to a chunk of Uganda in the east.

Toxicodryas adamanteus achieves a maximum of 125cm and an average of 80-120cm, and appears in forests, woodlands, and savannahs interspersed with tree clumps. Some trees are essential – Toxicodyras adamanteus never appears in bare hills or grassland. As their savagely vertical pupils hint, this is a nocturnal snake, which climbs its trees slowly and carefully. During the day, eagle-eyed forest explorers can find them curled up in tree hollows, empty bird’s nests, natural joins in branches or tangles of epiphytes growing on trees.

This species has a red tongue tipped with white. “Adamanteus” is a Latin term for diamond-shaped markings, referring to its patterns. It’s the same as the east-diamondback rattlesnake, AKA Cotalus adamanteus. Toxicodryas adamanteus is non-lethal, but also non-cowardly. When threatened, they hiss loudly and make repeated mock strikes, or suck in air and inflate their chest.

Originally, this was part of a far-reaching African species: the powdered cat-eyed snake (Toxioydras pulverulenta). The two are similar in appearance, but in 2021, analysis revealed that those east of the Niger River Delta, which forms a natural barrier against migration, were actually an independent species: Toxicodryas adamanteus. To the west, they remained Toxicodyras pulverulenta.

A gold-black snake with small, round eyes, and a sharp snout which is probably used for shifting soil aside in burrows. Scaphiophis albopunctatus ranges from Kenya and Tanzania to Sierra Leone in the far west, and is part of a small, 2-member genus, the other member being the Ethiopian beaked snake.

This is a snake occasionally of rainforests, but usually open savannah, bushland, thickets and miombo woodlands. The largest male on record measured 115.5cm, collected in Shinyanga District, Tanzania. The largest female measured 151.2cm, collected in Upper Nile Province, Sudan.

The grey beaked snake has an elaborate intimidation tactic. They begin by showing off their deep blue tongue and inside of mouth. Then they launch themselves into the air in a savage strike, with enough force that most of its body leaves the ground. Its brutal hunting strategies involve invading mice burrows and pinning them against the wall, suffocating them without actually constricting. They’re also known to take refuge in vacant ground squirrel burrows for shelter. So far, most of Scaphiophis albopunctatus’ prey observations are of rats or mice. One 38.4cm snake had 4 newborn rats in its stomach.

A non-venomous snake which averages at 40-70cm and peaks at 120cm. A consistent brown-grey colour is a hallmark of the brown house snake (Boaedon fuliginosus). They’re a member of the large 22-member Boaedon house snake family, and have extremely flexible habitats, appearing in forests, woodlands and savannah alike.

Like the cape house snake of South Africa, this is one of most tolerant snakes in Uganda of urban environments, appearing in gardens, and polluted areas where no snake should be able to survive. Some herpetologists consider the brown house snake to be the most common snake in East Africa. They even enter houses in their constant search for rodents. As a nocturnal snake, they prefer to lurk under cover objects during the day, like rocks, but maybe assorted junk in your backyard, causing villagers to accientically step on one.

This species is recognisable by bulging eyes with a vertical pupil, and eye colour identical to its scales. Boaedon fuliginosus is an extremely widespread snake, spanning thousands of miles. They range from Morocco in northwest Africa to Mozambique in the southeast, with Uganda lying in the centre. However, it’s believed that Boaedon fuliginosus actually contains 7 species or more, which are “cryptic” species; i.e. they’re virtually indistinguishable to the naked eye, yet may have diverged millions of years ago. For now, those in Uganda are still classified as B. fuliginosus.

Perhaps the deadliest snake in Kenya, due to a deadly dance of airborne venom jets spat from holes in its fang tips, and the regular venom injected through a bite. Ashe’s spitting cobra was only made an official species in 2007, when it was split from the black-necked spitting cobra due to its blatant colour difference. This is the largest spitting cobra of all, at a maximum of 2.7 metres.

Naja ashei inhabits drier areas of eastern and northern Kenya, favouring semi-deserts, coastal thickets and dry savannah. They’re able to eat venomous snakes, including puff adders (Bitis arietans) and even their red spitting cobra (Naja pallida) cousin. White-throated savannah monitors are also confirmed prey. Ashe’s spitting cobras like to dash around the countryside in an overeager state, but they also like to shelter lazily, particularly in vacant underground burrows or termite mounds.

Mount Kasigau, Kenya is a confirmed zone for them, and bite symptoms include blistering, swelling, necrosis, and other local tissue damage. The venom contains an ingredient not found in other spitting cobras: cobra venom factor, comprising 0.12% of toxins. This inhabits complement C3 protein, thus weakening the body’s healthy inflammatory and immune responses. Otherwise, its venom is similar to other spitting cobras, containing 69% three finger toxins, and 27% PLA2s. Generally, spitting cobras are far less neurotoxic than other cobras, specialising in local destruction.

There are many Dasypeltis egg-eaters in Africa, but the montane egg eater (Dasypeltis atra) controls northern Tanzania, a chunk of Kenya, and Uganda. Montane egg-eaters are found above 1500 metres, in high altitude forests or savannah, up to altitudes of 2800 metres. This includes the hills near the capital Nairobi, located at 1795 meters above sea level. While they’re most concentrated in the high plateau of southwest Kenya, they’re also found in the Taita Hills of southeast Kenya, as discovered in 2015. Dasypeltis atra also appears on the forested slopes of Mount Kenya, though they’re not cunning and watchful defenders like the Mt Kenya bush viper.

Dasypeltis atra swallows both freshly laid eggs and those with half-matured embryos. They initially swallow eggs whole, with a bulge like a bowling ball moving down their throat. Then they writhe and flail around, cracking the shell with their sharpened vertebrae. The nutritious liquid spills into their belly, while the flattened and crushed shell is regurgitated.

This snake has many colour morphs. There’s car tyre black like above, sandy beige to disappear into bare soils, and brown overlaid with fine white markings. The eye colour follows the morph: black ones have black eyes, beige ones golden eyes, and reddish ones red-tinged eyes. Their pupil is vertical, though this is impossible to make out in black morphs. Dasypeltis atra is a nocturnal snake, which retreats to tree hollows and abandoned birds’ nests by day, which are well chosen for disguise. The inside of their mouth is a rich velvety black, which is the last thing an egg will ever see. Montane egg eaters often bare this black mouth wide to intimidate predators, while making repeated mock strikes. It’s all a ruse, as their teeth are way too tiny to inflict serious damage.

If you want to climb Mount Kenya, the country’s highest mountain, from the southeastern direction, then you must tiptoe past a deadly guardian: the Mount Kenya bush viper (Atheris desaixi). This is an extremely rare snake which clings to branches most of the day, in ambush posture, and reaches a maximum length of 70cm.

Atheris desaixi is confirmed in just two locations: the southeast flanks of Mount Kenya (altitude 5199 metres), and the Nyambeni mountain range just to the northeast. Mount Kenya bush vipers begin life as a plain yellow with a white tail tip. In adulthood, they develop grey-green scales each with pale edge, that create a spotted appearance.

Though armed with a destructive anticoagulant venom, which likely triggers haemorrhaging in victims (no detailed reports exist), Atheris desaixi has other defensive tricks to deploy. They often rub their keeled scales together to produce a loud sawing noise, like the saw-scaled viper of India. They at least try to give encroachers on their secluded forest slopes a warning. Captive keepers have noticed how they cease this nervous sawing as they grow comfortable in their terrarium. Mount Kenya bush vipers are one of Africa’s rarest venomous snakes, and are found exclusively in Kenya.

A rare snake, with only scattered records across eastern Africa. Its empire is large, spanning from southern Chad to Tanzania, with Kenya squarely in the middle, yet its confirmed locations often have hundreds of miles between them. Rukwa sand racers (Psammophis rukwae) are thin-bodied and reach a confirmed maximum so far of 147.8cm, discovered in Kafukola, Tanzania.

This is a fast and twitchy snake, which is believed to use its agility to chase down lizards across the majestic African flats, and wrestle them down its throat. Despite the name, Rukwa’s sand racer prefers habitats with some moisture rather than bone dry deserts, including flood plains, grasslands and savannahs.

Psammophis rukwae is always a brown and beige snake, with a couple of distinct morphs. One is plainer, while the other has darker, parallel stripes stretching down its body. A plain yellow belly is another ID sign. Its scales are smooth to touch, if you manage to outwit it with its rapid speed. Rukwa’s sand racer has round pupils, moves by day, and hunts mainly using its advanced eyesight. Of the 33 Psammophis members, this is one of the most poorly researched.

A harmless water-loving snake with round pupils, which is particularly common in southwest Kenya. The olive marsh snake inhabits rivers, lakes, swamps, and of course marshlands, usually within moist savannahs. Their territory is large, stretching from Ethiopia to Mozambique, but they won’t appear without sufficient water to duck, dive and swim around in. The exception is rainy season, when the increased water sloshing around the Kenyan countryside allows them to travel far and wide.

Frogs, tadpoles, small fish and frogs eggs are on the menu for this Kenyan snake. They appear from sea level to a maximum altitude of 2200 metres, and are known as Kaputi in northern Mozambique. Olive marsh snakes vary wildly in colour. Those near Mount Meru in Tanzania are bright green overlaid with a maroon stripe, while a handful from the Congo have been pure black.

Olive marsh snakes have a maximum recorded length of 60.0cm, and an average adult length of 35cm. If grabbed by the tail, they suddenly spin their body, in order to detach the tail, and escape by the skin of their teeth. 43.6% of Natriciteres olivacea had missing tails according to a 1987 survey. This is a placid species which rarely attempts to bite. They’re an egg-laying snake, with a range of 3-11.

Another fast, whippy snake which charges down its prey and forces them down manually. Sudanese sand racers inhabit both moist and dry savannah, coastal thickets and high altitude grassland. They range from 0 to 2700 metres above sea level. They’re no threat to human beings and mainly inhabit western Kenya, zipping past lazy puff adders and weaving through the legs of zebras.

Psammophis sudanensis closely resembles the Rukwa sand racer, but is a fully distinct species. This time, nearly all individuals are adorned with parallel stripes running lengthways down their body, with stony grey contrasting against lighter grey and beige. The longest male Sudanese sand racer measured 121.0cm, while females are slightly longer, at an all-time species record of 132.5cm. Both were recorded in Torit, South Sudan.

The Sudanese sand snake is one of a few dozen species worldwide known to rub a strange secretion over its scales, using its nose, as though waxing itself. This is one of the serpent kingdom’s great mysteries, though one theory is that this substance prevents moisture loss, in baking arid environments.

Psammophis sudanensis mainly lives in eastern Africa, including Kenya and northern Tanzania. They can be very abundant in certain locations, as in a herpetological survey in Chad savannah, they were the single most common colubrid snake, making up 17% of 1010 colubrids collected. There’s also an outpost in western Africa, over a thousand miles away, where the species is far scarcer.

A species of parched and dry areas, rather than lush forests. This is a mildly venomous snake with a very thin body, but a large round head, resembling the handle of a whip. Telescopus dhara is a snake with a large, sprawling territory. Despite the name, Israeli catsnakes stretch from Oman and the UAE, through Egypt and Somalia and all the way to Kenya, which lies at the southernmost end of its territory. Unlike many of this list, Telescopus dhara is found only in the drier eastern and northern Kenya. Semi-desert and dry savannah are its heartlands.

Telescope dhara is a thoughtful and deliberate snake, which never dashes around in a rush like Ashe’s spitting cobra. Israeli catsnakes are nocturnal, and retreat to the safety of dry rock cracks by day. They’re no cowards, and will rear up, hiss and strike at opponents if their comfortable danger threshold is exceeded. No human deaths are known, but few bite reports exist at all.

In East Africa, the record length of Telescopus dhara is 100cm, and the average 50-80cm. One of their confirmed prey is the Kenya rock agama (Agama lionotus).

A snake of drier areas rather than forests, including semi-deserts and dry savannahs. This species occupies northern Tanzania, much of Kenya, and a swathe of Somalia. Red-spotted beaked snakes are especially common along the eastern Kenyan-Tanzanian border, lurking in coastal thickets and scrubland.

Rhamphiophis rubropunctatus is quietly one of east Africa’s larger snakes, reaching up to 240cm. The namesake red spots are mainly found in youths, or sometimes on its flanks, on the border between its pale ivory belly, and its redder body. This species should really be called the red-headed beaked snake; the redness suddenly gains intensity at the head, and this may be its most obvious ID sign. Otherwise, there are few patterns, just bright clean colours. Rhamphiophis rubropunctatus has round pupils, and a black tongue.

This is a venomous snake, secreting its toxin mixture from rear fangs. The exact chemical profile and lethality of the venom remains a mystery. They’re capable of spreading a small hood, mimicking a cobra. Rhamphiophis rubropunctatus is another species to rub its body with a strange waxy substance. Scientists even timed this rubbing behaviour and found it to last 154 seconds per average session.

A snake which has not been seen for 90 years. The Tana Delta smooth snake (Meizodon krameri) is known from just 2 specimens, discovered in 1934 near the Kenyan villages of Kau and Golbanti, in the Tana River Delta region. In 1985, these stored individuals were reanalysed and declared to be not Meizodon regularis, but an all new species. It differed by having fewer ventral (belly scales), and 26 maxillary teeth versus 23. The two 1934 snakes measured 32cm and 50cm.

Since 1985, there has been no update. The Tana Delta smooth snake may be extinct, but it’s more likely a master at flying under the radar. The Meizodon family is especially secretive. Semiornate snakes (Meizodon semiornatus) are widespread in Mozambique and South Africa, yet are rarely encountered by villagers, such is their liking for cover objects like logs, rotting leaves, stones and overgrown vegetation near streams.

Meizodon members are uncomfortable when exposed, and this is why the Tana Delta smooth snake remains hidden till this day. Bookmark this snake in your mind for a future “lost snake rediscovered” media frenzy, so that you can smugly inform your friends that you’ve already heard of it.

A water-loving species, which is abundant around the capital of Nairobi. Battersby’s green snake is a pure green with no patterns, varying from duller light green to full grassy green like above. Spotting one is a hopeless task when in the middle of juicy reeds, water-lillies and thick riverside vegetation. There is a small white base to each scale, but this is only visible when they inflate their body as a defensive warning.

Battersbyi’s green snake is a climbing species, but is almost always found in bushes or trees close to a water body. They also have the power to hunt underwater. There’s no dangerous venom, but Battersbyi’s green snake has sharp teeth and knows how to use them. When biting, they wrestle their head from side to side to create deeper and more extensive lacerations.

This snake reaches a maximum of 90cm, and large bulbous eyes are one memorable feature. They’re also common in Rubondo Island National Park, in Lake Victoria in far northern Tanzania. This is a close relative of South Africa’s green watersnake (Philthamnus hoplogaster), but that snake has a higher number of ventral (belly) scales than P. battersbyi.

The yellow anaconda is the slightly smaller, yet still enormous cousin of the green anaconda, reaching a maximum of 4.6 meters, with a thick body for merciless constriction. This species lives further south than the green anaconda, primarily following the Paraguay river and its tributaries. This means that Paraguay itself is at the centre of its domain, alongside northern Argentina and Bolivia.

Yellow anacondas are found in wet areas of Paraguay, most likely lurking in shallow waters, or the edges of marshland, hoping to seize passing mammals, even dragging them underwater to drown them like a crocodile. Yellow anacondas are unusual among snakes in that a huge portion of their diet consists of wading birds, including Muskovy ducks and neotropic cormorants. If you send a stork carrying a letter to Paraguay and never get a response, then the yellow anaconda is probably to blame.

While yellow anacondas require water, they cope well with urban areas, even appearing in the Paraguayan capital of Asunción. This is an abundant snake in Paraguay, and is estimated to number several million worldwide. Virtually any large marshland in Paraguay could contain them, and they’re fairly easy to notice with their golden tones.

A nocturnal snake with powerful constricting abilities. This is a non-venomous species which humans can walk safely past without worrying about a surprise savage attack. The most they can achieve is squeezing your arm tightly if you pick them up.

The two-coloured mussurana (Mussurana bicolor) reaches a maximum of 99.0cm, and shares its habitat with the yellow anaconda: the Paraguay river, its tributaries, and its drainage basin. The two snakes often appear close by to each other.

Two-coloured mussuranas are fairly flexible, inhabiting riverside gallery forests, swamps and dry topical forests. Their diet is wide, including frogs, fellow snakes, small mammals and lizards, with a specific prey being the pointedbelly frog (Leptodactylus podicipinus). Mussurana bicolor also bites its prey while constricting, to secure an extra hold, and prevent a sudden burst for freedom. One two-coloured mussurana was spotted raiding a bat colony in the roof of a hostel, 2 metres high. Generally though, this species sticks to the ground. The shimmering red-black colours are a giveaway for this species, while their eyes are jet black.

Two-coloured mussuranas were originally placed in the Clelia family, alongside Clelia clelia, South America’s most infamous snake-eating snake. But in 2009, they were moved to the 3-member Mussurana family. Another study from eastern Argentina found a diet of 63% frogs and toads, and 37% lizards.

Part of the the huge, 55-member Erythrolamprus snake family, and probably the most common member. The yellow-bellied liophis (Erythrolamprus poecilogyrus) measures 70cm, and ranges from northeast Brazil to central Argentina, placing Paraguay squarely in the middle.

This is a venomous species, though not a dangerous one. A bite to a 1.71 metre tall victim in 2010 caused a swollen right hand, lasting 7 hours, and muscular pain spreading up the entire arm, which began to subside within 3 days. No antivenom exists, and its annual terror quotient is low. Yellow-bellied liophises occupy many habitats, including grassland, marshes, forests and occasionally urban areas. However, they require a water source, as this is a semi-aquatic species, like its close relative, the golden liophis of Uruguay.

Wherever it lives, thus is a very common species. During a survey of southern Brazil’s Pantanal wetlands, scientists detected 33 snake species. Yellow anacondas and Brazilian smooth snakes ranked 2nd and 1st, but the yellow-bellied liophis was close behind in 3rd. According to a 2015 study from Argentina, over 98% of their diet is frogs and toads, the tiny remainder being lizards. The yellow-bellied liophis apparently tastes good itself, as it’s feasted upon by snakes like the venomous painted lancehead.

Another member of the mussurana clan, this has the most flexible habitats of all. Again, this is a constricting snake with a patternless black back in adulthood. Their belly varies from ivory to red, making some look like the red-bellied black snake of Australia. This species hatches at 35cm and grows to an adult length of up to 180cm.

False mussuranas (Boiruna maculata) appear all over the place in Paraguay: moist forests, dry chaco and parched desert alike. They were originally discovered in 1896 in Uruguay. This is a multi-skilled snake, combing powerful constriction with a nasty venom, whose properties are not fully understood. In 2021, a 50 year old man bitten on the first right finger experienced swelling from the fingers to upper arm. A small necrotic zone appeared around the bite. No antivenom was administered, because the scientists struggled to identify the species at first.

In a 2002 study, snakes comprised 33% of their diet, lizards 16.5% and mammals 12.5%. They have numerous confirmed snake prey, including forest flame snakes, Patagonian racers and the venomous crossed pitviper and South American rattlesnake (also on this list). One brown mussurana tried to hunt a Jaeger’s ground snake, but it was so thin that the mussurana couldn’t constrict it, forcing it to rely on its backup venom instead. Brown mussuranas are a popular species in captivity overseas.

A nocturnal aquatic snake, which is a particularly strong swimmer, able to withstand fast-flowing currents. Helicops leopardinus particularly favours watery areas with plenty of floating vegetation. Their colours are variable, but always complex and boggy, as though they’ve absorbed the essence of a swamp. They reach a maximum of 1 metre and are considered by herpetologists to be aggressive.

Helicops leopardinus has dots all over Brazil, but their heartlands are far southern Brazil, northern Argentina and most of Paraguay. They particularly favour areas with floating vegetation. It’s very rare that you won’t find the leopard keelback dripping with water. This snake would die within minutes if dropped into the Mojave desert.

This is a very common snake in certain locations. In the study from Brazil’s Pantanal wetlands where the yellow-bellied liophis ranked third, the leopard keelback was the 5th most common of 33 snake species. Their diet is what you’d expect from a diehard water-lover: 62% fish and 38% frogs and toads. They’re able to hunt these prey at a variety of water depths.

Specific amphibian prey of the leopard keelback include lesser snouted tree frogs and pointedbelly frogs, also a prey of the two-coloured mussurana. All 20 Helicops members live in South America. The furthest afield is Daniel’s keelback (Helicops danieli), which just falls short of Panama (though hidden populations could lurk there).

The only rattlesnake of South America. Crotalus durissus covers thousands of miles from north to south, beginning in Colombia and ending in central Argentina. Paraguay isn’t exempt from their lethal ways. This snake barely warns its victims before unleashing a strike, and can easily kill via kidney failure.

The image above was actually taken in Paraguay, so know what to look for – a thick viperid body and beige-grey viper patterns, with triangles that morph into a stripe along the neck. Search for the rough, crinkly scales.

Though this snake covers all of Central America, we have a report from a Paraguayan individual specifically: a herpetologist who suffered respiratory failure and only survived following antivenom administration. He also experienced a rise in bloodstream creatine kinase, a marker of muscle tissue damage. Crotalus durissus is rare among the 50+ rattlesnakes of the Americas in that it’s highly neurotoxic. Most specialise in haemorrhaging and necrosis, but Crotalus durissus can highjack brain signals and trigger limb paralysis and respiratory failure. Tiger rattlesnakes and Mojave rattlesnakes are another rare pair with this profile.

There are sightings of Crotalus durissus from all over Paraguay – no regions appear to be exempt. The confirmed record length is 1.9 metres, with an average of 1.5 metres.

A copycat snake which attempts to mimic venomous crossed pitvipers in order to survive. This snake has the skill of eating poisonous amphibians like the common lesser toad, with enlarged adrenal glands that prevent the heart rate slowdown from bufotoxins. Wagler’s snake (Xenodon merremii) is common all over Paraguay and southeast Brazil, and reaches a maximum of 1.2 metres. They can inhabit forests or damper open areas, but always require water, as frogs are their main food source. This is a snake you can walk past without any worries. Their interest in amphibians is about 97%, and their interest in humans 2%.

Within Paraguay, Wagler’s snake has 4 distinct morphs: 1) banded pattern, 2) smooth (like above), 3) slightly marked, and 4) marked, the latter being the main viper-mimicking pattern, and the most common. All juveniles possess the marked pattern.

Analysis of its venom reveals toxins normally found in vipers, such as three finger toxins (3FTx) and snake venom metalloproteinases (SVMPs). However, a study tested 123 Wagler’s snake bites from São Paulo, Brazil. It found only non-lethal effects such as erythema, mild edema and pain. They concluded that “most accidents caused by X. merremii and X. neuwiedii present mild local symptomatology“. Wagler’s snake was milder for swelling than its cousin, Xenodon neuwiedii. Its venom is clearly targeted towards prey rather than deterring predators – hence why it must be a copycat.

This snake is the sole member worldwide of the Palusophis family. Originally, it was categorised in the same Masticophis family as the salmon-bellied racer of central America, but it was split off in 2018 into an all new group. Rio tropical racers range from Bolivia to southeast Brazil, with most of Paraguay potentially containing them. Moist forests are their realm, particularly swampy areas, as swamp racer is an alternative title for them.

This is a fast and adventurous snake, not a lazy one which lurks under boggy swamp material. Palusophis bifossatus chooses from an ultra-varied menu. According to a 2007 study, its diet contained 44% frogs, 32% mammals, 16% lizards, 4% birds and 4% fellow sakes. Specific snake prey included a Patagonian green racer, and a 31cm black-headed snake (Tantilla melanocephala).

It’s common to see Rio tropical racers swimming through swamps with their heads bobbing up and down. They easily exceed 1 metre, and lay 4-24 eggs per batch. This species is far from invincible though. They have a particular tendency to lose their tail in adulthood, due to it ripping off in predators’ claws. A 1998 study on 119 museum specimens found that 46.7% of Rio tropical racers were missing a portion of their tail.

A common species in southeast Brazil and Paraguay. Guibe’s flame snakes measure up to 125cm, and prefer forest edges and more open areas. They don’t shun humanity, as their eggs have been found in house backyards in chicken enclosures, and beneath rocks by entrances to farmland.

Like the two mussuranas of this list, Oxyrhopus guibei is a constrictor which asphyxiates its prey. Yet this doesn’t give them an impenetrable armour, as they often fall victim to predators such as laughing falcons, plush-crested jays, and Aesculapian false coral snakes.

At under 40cm, Guibe’s flame snake eats reptiles exclusively, whereas rodents dominate at over 40cm. In a 1995 study, they skipped constriction for lizards, and swallowed them alive, headfirst. Guibe’s flame snakes have no time for stealth and patience. They simply pursue rodents as they move, before applying a sudden hold of coils. They occasionally eat geckos, but struggle to see through their carefully crafted camouflage.

This species mimics coral snakes for its protection, with alternating black-white bands followed by wide spaces of red. It almost gets every detail correct, but it seems to have made one critical error: the black-white bands don’t always match up on either side of its spine. Still, it’s probably enough to fool hungry birds part of the time.

A snake with a rounded snout which rarely exceeds 80cm. The Chaco sepia snake (Dryophylax chaquensis) is one of Paraguay’s shier, yet smarter snakes, which lurks under the surface and hopes that nobody notices their existence. It’s also known as the Chaco mock viper, for its grey-brown alternating patterns, which lack any trace of bright colour.

Dryophylax chaquensis feeds exclusively on frogs and toads, and will turn up its nose at geckos or mice. The Chaco sepia snake seizes frogs by their back, then keeps them in a tight mouth hold for 15-20 minutes, to gradually inject a weak venom, before finally swallowing. This snake dislikes having live frogs hopping around in its stomach (unlike India’s checkered keelback). Their favourite prey include the Matto Grosso oval frog and Chaco tree frog. Chaco sepia snakes are believed to opportunistically grab whichever frogs are most abundant in any particular area.

Top locations for this snake are dry forest (51% of sightings), wetlands (16%), wet savannahs (14%) and marshes (10%). They have a tidy, moderately sized range, including southwest Brazil, far northern Argentina, and most of Paraguay.