| 1 | Red-tailed green ratsnake |
Maximum length: 240cm.
The red-tailed green ratsnake (Gonyosoma oxycephalum) is a 160-200cm species found in the wet forests of Malaysia and Indonesia. They’re an arboreal species, living on branches, with only a mildly toxic venom. Red-tailed green ratsnakes are dangerously exposed on their branches, and therefore must seek alternative survival methods.
Their green camouflage is very strong, but far from impenetrable. As a predator closes in and its heart pounds away, the red-tailed green ratsnake keeps its face steady and performs a simple action: it reveals its tongue. This is one of the most distinctive in the snake kingdom, with a vivid blue stripe contrasting against black on either side. Simultaneously, Gonyosoma oxycephalum inflates its chest to reveal blue patches between its scales.
This sudden flash of alien colour is instantly shocking to an approaching predator. It would even shock most humans, causing us to instinctively flinch, despite being able to rationally assess that it’s just a harmless warning display.
To a hawk, which doesn’t have the added skill of logic (that we know of), the blue must send all their alert systems into overdrive. The hawk flees and the red-tailed green ratsnake lives to fight another day. This scheme probably fails sometimes too – the exact success rate has never been studied in the wild.
| 2 | Cottonmouth |
Maximum length: 189.2cm.
Cottonmouths do exactly what they warned they would: they bare their mouths to reveal a snowy white inside, which is the colour of cotton wool, with no patterns, contrasting vividly against their murky brown scales.
Cottonmouths measure 65-90cm, and range from Texas to Louisiana to Florida. They have a cytotoxic venom that causes local effects like severe swelling, but rarely fatalities. Though dangerous themselves, they have a huge amount of predators in their murky swamps, including snapping turtles, alligators, blue herons, whopping cranes, and even largemouth bass. They need all the defensive strategies they can get, and if they can send a bird fleeing simply by opening their mouth, there’s no way they would refuse.
A greedy heron could spot a murky brown snake, and wade over excitedly, thinking they’ve found a tasty brown watersnake (a species which coexists with cottonmouths). Suddenly, they see a flash of white, which reveals their foolish mistake, and the heron flees to the opposite shore, amid a piercing hiss.
This tendency proves that cottonmouths aren’t as murderous and demented as the legends state. Do cottonmouths really chase fishermen from boats, follow them through boathouses, and slam into car doors as their victims close them at the last minute? No – they’d much rather warn you with a vivid white mouth, and not enter the chase at all.
| 3 | Thornscrub vine snake |
Maximum length: 152cm.
A mildly venomous tree snake, which ranges from Mexico to far southern Arizona, and is the most northerly member of the vine snake clan. Thornscrub vine snakes (Oxybelis microphthalmus) can reach 1.5 metres, but are incredibly thin, skirting over the flimsiest of branches without snapping them. They can fasten a prehensile tail to branches and dangle down, plucking up prey species like anoles.
The one thing Oxybelis microphthalmus wishes it has is a powerful venom, but they combine several more imaginative strategies in order to compensate. First is kinking its body to resemble a gnarly piece of vegetation, and swinging in the breeze. This actually had nothing to do with the vine title – they were named from the pre-existing green vine snake. Second is a flash of bright warning colour, as like a cottonmouth, they bare their mouths wide open, but with a rich purple-brown colour instead of white.
The impression is of a lethal, finely tuned rainforest venom flowing through every fold of their mouth, completely false but highly convincing. Thornscrub vine snakes look completely crazy while flashing these colours, and they don’t rest on their laurels. They combine the display with a piercing hiss and a tight S-coil, as though a life-ending strike is imminent.
| 4 | Ringneck snake |
Maximum length: 85.7cm.
The ring-necked snake is one of the USA’s most humble species. They typically measure just 30cm and live in forests, often hiding in the safety of anthills. It’s possible to find dozens of ringneck snakes in an hour, as they regularly congregate under logs, rotting bark, or manmade objects like sheet metal. This gives them natural safety, yet racoons and red-tailed hawks are canny creatures and can easily tear away these shields.
Consequently, ring-necked snakes have evolved a strange defensive mechanism. When cornered, they’ll suddenly flip over, and dazzle their enemies with a bright underside. This bright underbelly varies from yellow to pink to bright red. While scientists aren’t sure how often it succeeds, the goal is believed to be stunning predators into leaving the area, assuming them to be venomous.
Ringneck snakes eat ants, earthworms, and small salamanders, while their own predators include broad-winged hawks and copperheads. They have at least 9 subspecies, with the namesake ringneck being the key ID feature. In the Florida keys subspecies, for example, the ring is very faint, barely visible.
Ring-necked snakes aren’t complete pushovers, and will bend their heads back and bite savagely. The sweet (or sour) spot is the neck – touch and they’ll bite without fail. Ringneck snakes occupy virtually the entire US southeast.
| 5 | Wall’s bronzeback |
Maximum length: 150cm.
This branch-loving snake inhabits southern Thailand, peninsular Malaysia and Borneo. They have a mild venom, but with virtually no effects in humans, as even a swollen arm would be a fluke beyond fluke. Wall’s bronzeback (Dendrelaphis cyanochloris) has a bronze head, a creamy-green belly, and a black stripe between, and finally, electric blue skin which is clearly visible beneath.
Dendrelaphis cyanochloris is commonly confused with its cousin the elegant bronzeback, which also has electric blue patches. But the blue is far more encompassing in Wall’s bronzeback, and they’re much more inclined to blast predators with these bright colours, stunning them momentarily, then sending them fleeing.
Wall’s bronzeback has blue colours visible constantly, but during pressure points, they’ll inflate their chest to spread their scales apart, revealing more of the interstitial skin between.
The likes of painted bronzebacks barely have this power, despite being far more common in Thailand. Perhaps the painted bronzeback has slightly superior speed and agility, ensuring their survival, but Wall’s bronzebacks benefit from their blue-blasting intimidation tactics, giving them a safety buffer against predators. Wall’s bronzebacks prey on a mixture of frogs and lizards, and have especially large eyes.
| 6 | Hagen’s pitviper |
Maximum length: 123cm.
A dangerous venomous pitviper of Sumatra, peninsular Malaysia and far southern Thailand. This species lives on jungle branches, and has a venom containing 216 identified proteins. There’s almost as many colours, as Hagen’s pitviper begins with the typical jungle green for a Trimeresurus pitviper. They have an electric blue upper lip, and a white line along their flanks. Between their scales, they have silky black skin which they can show off at will.
Hagen’s pitviper (Trimeresurus hageni) enjoys the best of both worlds, as in foliage, they have a complete cloak of camouflage, with such a leafy green body that it spreads to cover their eyes. At a distance, Hagen’s pitvipers are almost impossible to spot. But when cornered, they use their blue, white and black shades to create a shocking display of colours. No sane human being would want to stroke a wild Hagen’s pitviper.
The physical characteristics of a venomous snake aren’t taught in school, but are somehow universally understood. An adult Hagen’s pitviper looks venomously radioactive, as though every cell is pulsating with poison.
Hagen’s pitvipers rarely kill, but have a nasty venom rich in metalloproteinases, which causes necrosis and swelling of the skin tissue surrounding the bite site.
| 7 | Spotted harlequin snake |
Maximum length: 65cm.
The spotted harlequin snake of South Africa has a paintbox of bright colours. Some are yellow spotted, others have a bright red spinal stripe, but they’re always dazzlingly colourful. This is a mildly venomous species, which is capable of swelling up a finger, but not killing.
Spotted harlequin snakes (Homoroselaps lacteus) are found only in South Africa and the tiny nations of Lesotho and Eswatini. They generally prefer moister areas of South Africa, such as grassland, moist savannah and lowland forest. Their diet consists of legless skinks and harmless blind snakes.
Spotted harlequin snakes are sometimes found in abandoned termite mounds, but they can’t shelter forever. They measure just 40-50cm, making them vulnerable to predators. If a predatory bird swoops in, then they need a way to deter them, and bright neon colours often work. Many birds worldwide have an instinctive fear of such bright snakes, assuming them to be venomous.
It’s easy to imagine how the change would have spiralled out of control, using good old fashioned natural selection. The ancestor of the spotted harlequin snake 20 million years ago may have been far duller, but had its own ancestor 20 million years earlier with brighter colours. If the dull version had a rare mutation, a morph where the old colour genes were switched back on, that freak snake could have gained a sudden survival advantage, which the older ancestor didn’t have. Gradually, these colours would have spread, before the entire species was eventually bright and neon-coloured.
| 8 | Red-headed krait |
Maximum length: 207cm.
A venomous species of southern Thailand, peninsular Malaysia and Java. Red-headed kraits have a dark blue body, contrasting sharply against a red head. They live in moist forests and are rarely sighted by ordinary people.
Red-headed kraits can trigger paralysis and respiratory failure, or on a weaker level, laboured breathing and weak muscles. 56.2% of its venom is comprised of the infamous bungarotoxin-2.
A red-headed krait’s head stands out clearly, even at night when they’re most active. Their goal is to scare predators away, but this time, red-headed kraits are deadly serious in what they say.
Like a red traffic light, their bright head is an instruction to freeze and not come an inch closer. They’re saying that if you touch these bright colours, your inevitable fate will be 100mg of neurotoxic venom flowing through your bloodstream, with millions of molecules distributing to every muscle receptor, and physically preventing signals from binding.
A Thai snake which isn’t serious is the pink-headed reed snake, which has a similar colour scheme, but is non-venomous. A red-headed krait bite can easily prove fatal, and there’s no specific antivenom.
| 9 | Malcolm’s pitviper |
Maximum length: 133cm.
Malcolm’s pitviper is a deadly species of Borneo, the large island split between Indonesia, eastern Malaysia and the kingdom of Brunei. Within this large island, they only inhabit a small territory: Mount Kinabalu National Park of the far northeast. Like Hagen’s pitviper, they belong to the 40 member Trimeresurus pitviper genus, but this species has a very different bright colour fear-fueling tactic.
As you can see, this species is just as green as its relatives, just as optimised for blending perfectly with jungle foliage. It also has the red tail for luring and deceiving prey that other members have. But this species also has a pale white mouth, with only slight hints of pink. Even its fangs are a pure snowy white.
When baring their fangs, these colours contrast sharply against their scales. It’s not proven whether this is designed to blast enemies with bright colours, forcing them to flee. But the display is a strange parallel of the cottonmouth in the southern USA, despite the two having diverged tens of millions of years ago.
It’s highly doubtful that they even need this white mouth, as their ferocious expressions and long fangs are just as terrifying. Apart from their white mouth, this species might have some of greatest jungle camouflage of any pitviper.
| 10 | Black pipe snake |
Maximum length: at least 60cm.
Black pipe snakes (Cylindrophis melanotus) are found in Indonesia, only on the Sulawesi Islands and nearby smaller islands. Their colours are some combination of jet black and red, occasionally with white instead of red. This species appears in various types of forests, shying away from human settlements.
Ordinarily, this species is a shy black serpent grinding along the forest floor, giving them excellent disguise in the cloak of darkness. They often rest on thick beds of leaves, giving them another instant escape avenue they can exploit. But if this species is cornered by a bird, whose reactions are just as fast as they are, they can deploy another weapon – a sudden bright colour flash. Like other Cylindrophis members, the black pipe snake lifts up its tail to reveal the red underside, both to distract from the head, and create a sudden flash of colour.
The strange thing is that this colour scheme closely mimics venomous snakes as well, including the red-headed krait and Malaysian blue coral snake. Yet neither of these species actually exist on Sulawesi.
The explanation might be birds, who can fly between islands, and therefore still fall victim to mimicry in snakes which don’t actually coexist with the target snake. Or the snake they were mimicking might be extinct – grass snakes in the UK occasionally spread a hood to mimic a European cobra that no longer exists.
Other pipe snakes include the Sri Lankan pipe snake, which has a snowy white tail. The most common worldwide is the red-tailed pipe snake, whose tail is similar, but has a banded body instead.