| 1 | Broad-banded copperhead |
Maximum length: 94.6cm.
Snakes have evolved many skills over their 100 million years of existence. One that exists in only a few dozen is caudal luring – when snakes wiggle a colourful tail to tempt in prey, which mistake it for insects, and are then devoured.
One example is the broad-banded copperhead, a resident of the middle US, including Texas, Oklahoma and Kansas. The copperhead is a slow and patient species all around, and deploys this patience for careful, mesmerising tail waggling. It lurks silently on leafy woodland floors, blending in with its immense camouflage, ignoring other woodland creatures like foxes that walk past.
If bitten by a broad-banded copperhead, then the likely consequences include skin tissue destruction and spontaneous bleeding. Its tail, meanwhile, is a swampy green colour, contrasting sharply against their beige body.
If waggled at just the right speed, this resembles an insect floating absentmindedly around the woods, or perhaps a tasty piece of vegetation. One theory is that the tail is designed to resemble a caterpillar. A frog or lizard walking past will notice this green speckle, and approach eagerly. If it fails to recognise the deception, then the small creature will be swallowed whole, giving the broad-banded copperhead a tasty meal without leaving its ambush position.
Like many vipers, broad-banded copperheads lose this colourful tail tip with age, as their venom grows steadily more potent, reducing the need for deceptive tactics.
| 2 | Northern eyelash boa |
Maximum length: 35cm.
One of the kings of the tail luring snake world, despite rarely exceeding 30cm. The northern eyelash boa is named for small spiky scales above each eye, although these are incredibly difficult to see given how tiny they are.
Even finding this snake is impossible. Firstly, they live in the depths of the rainforest. Secondly, they’re tiny. Finally, they have incredible camouflage, blending into mud and rain-soaked forest matter with ease. This makes their bright yellow tail all the more effective as a lure, as it’s often the only part that curious animals can see.
Northern eyelash boas move extremely slowly, and are active at night, which just adds to their inaccessibility. They’re found in western Colombia, but Ecuador is their main base, where they’re found to the west of the Andes. Their diet includes fish, tadpoles, and small frogs, which are probably the main focus of their tail luring ways.
Northern eyelash boas lack any form of venom, or aggressive non-venomous fangs, so their bright tail is one of their main weapons, and it seems to be working so far. The only possible fear is that the longer eyelash boas keep their tail waggling schemes up, the more frogs will adapt. There’s probably a few sharp frogs already who realise that they’ve a glimpsed a serpent tail and not a tasty insect. These frogs will be more likely to survive and spread their genes, and eventually their numbers will rise.
In the future, a tipping point may be reached where frogs no longer fall for the eyelash boa’s games, forcing the snake to develop new tactics. This scenario might take millions of years, but it’s surely inevitable.
| 3 | Southern death adder |
Maximum length: 100cm.
The thickest-bodied venomous snake in all of Australia. Rather than a viper like most “adders”, the death adder is actually an elapid, like a tiger snake or coral snake. This species is found near bushy trails and forest edges, where there’s plenty of cover to lurk in.
Death adders rely heavily on ambush, and one method they use to increase their success is a bright tail tip. Their yellow tail contrasts sharply with their darker body, and by wiggling this tail at a mesmerisingly slow rate, they can convince lizards or mice that they’ve spotted a juicy morsel of food. Their diet heavily consists of rodents, but is relatively flexible.
Death adders don’t rely on tail waggling exclusively, as they deliberately position themselves in bushes next to well trodden mammal trails, allowing them to spring out in milliseconds. The tempting tail tip is simply a nice bonus which increases their survival chances by around 2%. This small advantage might be enough to help them endure when other species go extinct.
There’s 8 death adders in Australia, but this species is the most common. Common death adders (Acanthophis antarcticus) are found all over eastern and southern Australia, reaching as far north as Cairns.
| 4 | Bothrops bilineatus |
Maximum length: 123cm.
Many Bothrops pitvipers (such as common lanceheads) have bright tail tips as younglings, which fade with age. Before their venom reaches full potency, they need alternative hunting strategies. But Bothrops bilineatus is one of the few to keep a colourful tail into adulthood and old age.
Despite a cytotoxic venom which tears through skin and muscle cells, rendering small frogs completely immobile, this rainforest species keeps caudal luring as a handy backup, a way to stack the cards ever further in their favour. This the most branch-dwelling Bothrops pitviper, and can go many days without moving.
Bothrops bilineatus can reach branch perches 20 metres above the forest floor, and eats prey such as red-snouted tree frogs and Marmorea frogs. They’re widespread across the entire Amazon region, and cannot survive without forests.
Exactly what triggers a snake to start waggling its tail is unknown, but we can make educated guesses. In some cases, it might be a regularly scheduled probing wiggle, designed to flush out prey which might be lurking out of sight. But snakes like Bothrops bilineatus might also pick up a lizard’s scent in the air, realise they’re approaching, and then kickstart the luring process.
| 5 | Common lancehead (as juveniles) |
Maximum length: 172.3cm.
Earlier, we mentioned how many Bothrops pitvipers of the Americas lose their bright tail tip as they mature. This is true for the most infamous, dangerous and widespread member of all – the common lancehead (Bothrops atrox).
This species ranges from eastern Colombia through the vast majority of Brazil, also covering Venezuela, eastern Peru and Ecuador, French Guiana, etc. In some Amazonian regions, this species causes well over 50% of venomous snakebites. Common lanceheads lack neurotoxins, but pump in a potent elixir of cytotoxins and haemorrhagins.
The image above is a juvenile, and shows a banana yellow tail contrasting against the typical dull viper shades. The beige-brown are perfect for camouflaging on the forest floor, while the tail is perfectly irresistible for their chosen forest prey. Despite the image, common lanceheads generally spend their time on the ground, particularly in manmade cocoa and coffee plantations. They use ambush tactics like other Bothrops members, and this youthful bright tail increases their chances substantially.
Precisely why the tail disappears with age is inconclusive, but we have some clues in a huge study from 2020, which examined the diet of 612 common lanceheads. As adults, they preyed on 56.3% mammals, 28.1% lizards, 9.4% frogs and toads. This was a large change compared to juveniles, which preyed on 44% lizards, 20% mammals, and 10.7% frogs and toads.
The disappearance of their bright tail tip may be because their adult prey are less likely to fall for it. Alternatively, it might be that their lunge distance and strike accuracy increase with age.
| 6 | Mexican cantil |
Maximum length: 138cm.
Out of all vipers, the Mexican cantil is one of the easiest to observe with a bright tail tip. This species is found in dry, crunchy woodlands of eastern Mexico, through to Guatemala and El Salvador. It’s becoming steadily more endangered, as the dry woodlands they inhabit are less likely to be protected than rainforests.
With that in mind, Mexican cantils need all the survival skills they can get. One is a pulsating venom loaded with haemorrhagins, which typically cause swelling and spontaneous bleeding in human victims. Another is a bright tail designed for luring small prey, which is found in all juveniles, and sometimes survives to adulthood as well.
Mexican cantils have some of the best caudal luring observations of any snake. One captive keeper received a juvenile Mexican cantil in 1978, and observed it raise its tail vertically into the air by 4-5cm, then hook the bright coloured tip. One time, it wiggled it slowly back and forth, while a second individual he received in 1987 performed a similar wiggle lasting for 5 minutes, again with its tail raised vertically.
In another old report, Mexican cantils used caudal luring to capture 3 recorded species: an oak toad, anole and tree frog. The bright tail of this species is particularly easy to spot in the wild due to their dark bodies. Mexican cantils begin life as a dark brown, and only grow darker with age, eventually becoming fully black except for a few starry white lines.
Interestingly, in the two first observations above, no prey had been introduced to the Mexican cantil’s cage. So this species clearly performs regularly scheduled wiggles, hoping to flush out prey which may be lurking, rather than actually waiting for a clear scent to appear.
| 7 | Lesser Sunda pitviper |
Maximum length: 93cm.
Another snake which doesn’t need caudal luring, as it possesses a corrosive cytotoxic venom, which physically dissolves the tissues of animals. Yet the Lesser Sunda pitviper keeps its bright tail anyway, for the simple sake of being overpowered.
The venom of this species is rich in metalloproteinases, and can cause swelling, necrosis and gangrene in humans. Small lizards don’t stand a chance. Nevertheless, this snake also likes to be subtle, and starts by extending their tail, poking it away from their body. Then they begin a slow, steady wiggling, in a rhythmical motion like a hypnotist’s chain.
Lesser Sunda pitvipers are found in a wide chunk of Indonesia, including Java, Bali and Timor-Leste. They vary in colour, as most are green, while a decent chunk are a pure turquoise blue. However, the bright red tail is a constant feature.
The final piece of the caudal luring puzzle is a lightning fast pounce. Lesser Sunda pitvipers can stay still for many hours, but explode into action when their prey finally treads close enough. Dozens of scales suddenly shift at once, and the poor lizard is being rearranged for swallowing before it realises what’s happening. Their only hope is dodging, as there’s no escape once they’ve been caught. Perhaps the pitviper will delay for just half a second, just giving the lizard time to flee the scene with a sudden burst of adrenaline.
| 8 | Malayan pitviper |
Maximum length: 100cm.
A lizard is starving and hungry. It hasn’t eaten in hours, and its reptilian acquaintances are just slightly faster. It looks up, and suddenly, it sees an orange dot floating a few metres away.
The lizard breathes a sigh of relief, and dashes forward eagerly. The floating dot gets bigger, and at the last second, the lizard feels uneasy, but it’s too late, and it is swallowed by a huge pair of serpent jaws. The lizard has just fallen victim to the treacherous ways of the Malayan pitviper (Calloselasma rhodostoma), one of southeast Asia’s top tail-wagglers.
The Malayan pitviper lives in Thailand, Cambodia and Vietnam, lurking in woodlands with an abundant covering of leaves on the floor. Malayan pitvipers can acquire prey via traditional ambush tactics, waiting for prey to walk past. But waggling a colourful tail speeds things up nicely, drawing in potential prey like a tractor beam.
This tail is particularly pronounced in young Malayan pitvipers. This species varies in colour – some are pink with an orange tail (see above), while others are dark grey with a white tail.
The Malayan pitviper is officially the top snakebite offender in Vietnam, causing 30.5% of venomous snakebites in a study from 2001 to 2002. The bigger problem for humans isn’t being lured in by a tail, but stepping on them as they coat their bodies with a thick layer of leaves.
| 9 | Cottonmouth |
Maximum length: 189.2cm.
Another snake belonging to the Agkistrodon genus, which also contains copperheads and Mexican cantils. The cottonmouth (Agkistrodon piscivorus) is infamous for many things, including leaping at fishermen from overhead branches, stalking humans for miles, and generally being a murderous maniac. None of these claims are true, but one true fact is that juvenile cottonmouths have a bright tail tip, which is probably designed for luring curious prey.
The exact prey which are lured isn’t confirmed, but juvenile cottonmouths are confirmed to prey on pig frogs, as well as moths and caterpillars. With age, the bright tail completely disappears, and their brown patterns grow less sharply defined, taking on an all-consuming swampy murkiness.
In 2021, it turned out that cottonmouths have a more impressive tail than anyone realised: their tail tip was proven to be fluorescent. Many vipers were examined, including broad-banded copperheads and Mexican cantils, and several were proven be fluorescent. In other words, absorbing photons and re-emitting them at lower wave lengths. Even the rattle segments of various rattlesnakes were found to be fluorescent.
The scientists theorised that at certain light intensities, this would give the tails a mesmerising glow, making them even more visible to certain prey, including frogs or lizards, depending on their visual capabilities. A green dot floating around a swamp would be interesting to a frog, but a green glowing dot would be even better (for the predator at least).
In the image above, the cottonmouth is bending its tail – the Mexican cantil was described as hooking its tail when waggling, so the position above may be the posture the cottonmouth uses to lure prey.
| 10 | Malcolm’s pitviper |
Maximum length: 133cm.
This rare pitviper is found exclusively in Malaysian Borneo, and even then, exclusively in the northeast corner, in the rich biodiversity hotspot of Mount Kinabalu National Park. It’s a dangerously venomous species with vividly green jungle scales, and a noticeably red tail, which contrasts sharply with its body.
Malcolm’s pitviper hasn’t actually been studied for its caudal luring tendencies. In fact, this rare Borneo species has barely been studied at all. But based on its highly red tail, and the tendency of other Trimeresurus members to use tail luring, even into adulthood, there’s a high chance that Malcolm’s pitviper does the same.
This isn’t their only weapon, as their mouth is shockingly snowy white. Like the cottonmouth, it’s possible that they suddenly flash these colours at predators to startle them into fleeing. That’s if they didn’t notice this snake’s freakishly long fangs beforehand.
This species is confined to an extremely narrow area, but in their Mount Kinabalu heartlands, it’s a common species. Its closest relative is the Sumatran pitviper, which also possesses a bright red tail.