| 1 | Green bush viper |
Maximum length: 65cm.
Although snakes drink rainwater, they don’t drink like a human, gulping down huge satisfying mouthfuls. Nor do they lap up water like a dog. Instead, a snake’s mouth is lined with endless small grooves which absorb water like a sponge, which are then forced down using muscular actions.
Some snakes then upgrade to a level beyond this, and don’t even seek out a small pool or stream to drink from. Instead, they just sit there calmly and allow rainwater to accumulate on their scales, which they later lap up.
The green bush viper (Atheris chlorechis) of west Africa is one of several species worldwide confirmed to use this trick. This is a jungle snake, and an especially lazy one, which waits for days in ambush and only moves when lunging at prey, or seeking out a new ambush site. Green bush vipers are found in forests exclusively, never venturing into towns. Their cousin is the hairy bush viper, one of Earth’s most bizarre snakes.
To fulfill their ambush lifestyle, green bush vipers only eat every few weeks, and have scales optimised for collecting water. They can spend hours staring into space, calmly observing any small movements in the forest, before occasionally bending their neck back to drink water off their own body. This rainwater trick is one of several adaptions that make their entire lifestyle possible.
| 2 | Bothrops moojeni |
Maximum length: 230cm.
One of southern Brazil’s deadliest snakes. Bothrops moojeni already looks rough and crinkled from a distance, and these furrows are perfect for collecting falling rainwater. This species isn’t completely immobile, living in riverside forests and tree clumps. But moving will spoil the ambush tactics they rely on, and rainwater collection forms a handy back up.
In a 2000 study, scientists analysed this water-collecting skill, and found that Bothrops moojeni coiled up the moment water struck its body. It kept its coils in very tight loops, to create a steadily building pool.
Bothrops moojeni didn’t suddenly work out how to do this, but evolved the skill slowly. One of its ancestors must have had subtly different scales, which reached a tipping point whereby it collected moisture more effectively. This turned out to have survival advantages, and before long, the entire species was now a new, updated version with a next level survival power.
This species can turn aggressive if cornered by humans, hissing and baring their teeth. With a cosy riverside habitat, plenty of mammal prey, and a cool rain-grabbing trick, Bothrops moojeni isn’t even close to endangered.
| 3 | Emerald tree boa |
Maximum length: 210.8cm.
This Amazon species is one of the most immobile snakes in the world, and certainly the most immobile large boa. The life of an emerald tree boa (Coralls caninus) looks extremely boring to an outsider, although we have no idea what’s going on in their minds. They never leave their branch perch, and swing down only to lunge at tempting mammal prey.
For week after week, the emerald tree boa sits still, staring menacingly. Not even a photographer waving a camera in its face can persuade it to move.
Days, even weeks pass, in which the emerald tree boa only raises its head to analyse a spiny rat in the distance, before sinking back into its coils, expression unchanged. A tiger ratsnake slithers past. The emerald tree boa doesn’t react. A monkey gets carried off by a hawk before its very eyes. The emerald tree boa still doesn’t react.
With such an overwhelmingly lazy lifestyle, the emerald tree boa needs a way to replenish its moisture, and collecting rainwater on its back is the perfect solution. The emerald tree boa doesn’t even have to try, as the rainwater accumulates automatically in its scales, before the boa swings around and takes a drink when ready. Emerald tree boas only venture to the ground in times of extreme stress, like if a bird is seconds from taking their life.
| 4 | Peringuey’s adder |
Maximum length: 32cm.
A desert-dwelling snake, whose body has adapted for survival in the most extreme of environments. Peringuey’s adder (Bitis peringueyi) lives in the sandy deserts of southern Namibia, even slithering down fully-fledged sand dunes. They’re not as immobile as the emerald tree boa, but can spend hours and hours hidden among dry rocks, using their favoured ambush tactics.
Peringuey’s adders are highly patient, waiting calmly until they hear the scampering of a barking gecko approaching, which gradually gains in intensity until they finally decide to pounce. To accomplish this, they need a reliable water supply, to avoid going crispy.
The likes of burrowing snakes have such smooth scales that water just runs off them. This is by design, as underground snakes need to avoid unnecessary soil clinging to them. Peringuey’s adder is the exact opposite, with jagged scales optimised for collecting small pools of water. They can even flatten their bodies to enhance the collection area. Ran is rare in the Namib desert, but they instinctively maximise ever drop they can.
The one obstacle Bitis peringueyi faces is an unusually dry spell, even by desert standards. In that case, they have another backup: condensing mist on their scales, when thick fogs roll in from the Atlantic ocean.
| 5 | Blunt-headed tree snake |
Maximum length: 155.4cm.
The blunt-headed tree snake (Imantodes cenchoa) ranges from eastern Mexico to northeast Argentina, preferring jungles, but also clearings along forest borders. They’re an actively foraging snake, much more energetic than an emerald tree boa. However, they stay still for long periods when resting or digesting food.
If you find this species, something you might notice is scales glistening with moisture, which they bend their neck towards and lap up droplets from. Rather than wasting time with a pond, blunt-headed tree snakes just drink off themselves.
The blunt-headed tree snake might have no arms, and it might be hunted by birds, but it never has to worry about water. This cool ability is found mainly in snakes, mainly because they’re one of the few creatures that can achieve it. A human being is nowhere near flexible enough to collect rainwater and drink it off his back. A gorilla, for all its brute strength, could never bend over backwards and drink off its own fur.
Meanwhile, even the bulkiest snakes like blood pythons are flexible enough to rest their heads on their backs. This is nature’s compensation for stealing their arms and legs.
| 6 | Western diamondback rattlesnake |
Maximum length: 233.7cm.
The western diamondback rattlesnake lives in dry areas from southern California to Arkansas, and is responsible for the highest number of snakebite fatalities in the US per decade. They feed heavily on mammals, and have an exceptionally loud rattle, but they’re also the single best studied snake when it comes to rainwater collection on scales.
If a caveman wanted to collect rainwater in prehistoric times, he would have to find a specially shaped rock, or summon up all his carving skills. The western diamondback, meanwhile, can just relax on its dusty rock slab. It can feel the rainwater pattering against its back, and know with satisfaction that its evening drink is steadily building up.
Western diamondbacks don’t just lie aimlessly on the ground, but form a deliberate coil shape to encourage water collection. Their scales are highly optimised, as a droplet striking a diamondback will break into several smaller droplets and cling to them. In their southern US neighbours, the desert kingsnake and Sonoran gopher snake, these droplets mostly slide off.
Each diamondback scale has a detailed nanostructure, with a network of tiny channels, just one tenth of a red blood cell’s width. The depth of these channels is optimised for water collection – adding slightly more or less depth would make them less effective. These features were discovered in a well publicised 2019 study.
| 7 | Coastal taipan |
Maximum length: 290cm.
The coastal taipan is the last snake on Earth that needs to collect rainwater. It’s fast-moving and energetic, travelling dozens of metres per day, and can lap up water from a small pond and move onto its next meal in no time.
Nevertheless, coastal taipans were officially observed licking water off their own scales in June 2019. The subject was a female basking in front of a dark burrow, which was motionless except for subtle movements of its head. Six short, sharp rain showers followed, and after each one, the basking taipan would lick water off itself. Coastal taipans are energetic, but apparently keep this subtle weapon as a backup in the occasional case that they need to stay still.
This taipan also swallowed rainwater from nearby vegetation. The scientists only realised that it was drinking rainwater after zooming in on the images later, as the droplets disappeared while the taipan’s face moved over them.
Among Australian snakes, green tree pythons are also known to collect rainwater on their scales, as they’re almost an exact clone of the emerald tree boa in South America.
| 8 | Sidewinder |
Maximum length: 84.2cm.
A species of Arizona and Nevada. The sidewinder rattlesnake’s motivations for capturing rainwater are simple – they live in bone dry deserts, and can’t let any moisture go to waste.
On the rare occasions that it rains, sidewinders have to save every drop they can. That’s where their automatic collection mechanism comes in. Sidewinders have rough, crinkled scales like all rattlesnakes, which are excellent at grabbing falling water droplets, like their western diamondback cousin. These droplets are prevented from falling to the desert floor wastefully, mingling with sand and becoming inedible.
Sidewinders can occupy the most extreme deserts, even Death Valley, and need all their skills to scrape out an existence. Their other adaptions include scales which change colour, from light during summer in order reduce sunlight absorption, to significantly darker during winter.
Sidewinders also gain water through their prey, 50% of which is lizards. Their rainwater-collecting skills aren’t used often, but without them, a dehydrated death would be almost guaranteed.
| 9 | Banded water snake |
Maximum length: 158.8cm.
The banded watersnake (Nerodia fasciata) of Florida is less lazy than the rest of our list, and doesn’t necessarily need rain-collecting skills, yet it has them anyway. This serpent has made the wise decision to stockpile as many snake powers as possible.
Banded watersnakes measure 65-105cm, and stick to water bodies like marshes and lakes, where they’re usually found in vegetation along the edges. They cunningly exploit many of the Earth’s natural resources: logs for shelter, branches to rest on, streams to dive into, and rainwater stored on their back for moisture.
This snake knows that rain is its friend, not something to fear. With no effort at all, the banded watersnake allows thousands of tiny droplets to combine on its back, and form a reserve reservoir of moisture.
The banded watersnake lives in temperate to humid zones, and isn’t under much pressure. You can find this species from Florida to Louisiana to southern Illinois. They have no venom, but will bite viciously if picked up. Their prey consists of fish and frogs, and their hunting style is mainly simple grabbing. Banded watersnakes overlap with brown watersnakes in the southeastern US, but are distinguishable by their namesake bands.
| 10 | Mamushi |
Maximum length: 91cm.
This 50-80cm snake lives in leafy woodlands of Japan, typically close to human inhabited areas like villages. Mamushis belong to the Gloydius pitviper genus, which are all venomous and number 26 across central and eastern Asia.
Rather than smooth and sleek, the mamushi is gnarly and jagged like an old tree trunk. This is a strategic advantage, as it allows them to collect rainwater in their scales, which they eventually drink.
Collecting rainwater isn’t just a cool gimmick for the mamushi, but vital for their hunting strategy. Patience is the key for an ambushing snake, and interrupting it for a trip to the village river would be disastrous. The entire local colony of rats would realise that there’s a hungry pitviper around, and be put on their guard.
The mamushi is fairly thick, yet still flexible enough to bend back and drink from their own personal rainwater pool with ease. This tendency was first observed in Hokkaido, Japan in 2002, in 3 sperate mamushis after brief rain showers swept in. What’s less known is how they react if animals try to steal their rainwater stash – extreme rage is most likely.