Desert-dwelling prairie rattlesnakes of the western U.S. are ultimate survivors, able to get by on just one hearty meal a year. But without a sip of water now and then, the snakes would shrivel up and hiss their last.
So how do these sit-and-wait predators stay hydrated way up in the Rocky Mountains, where standing water is scarce? Easy. They turn their bodies into rain-collecting bowls.
When it sprinkles, prairie rattlesnakes slither out in the open and coil up, says Emily Taylor, a snake biologist and director of the Physiological Ecology of Reptiles Laboratory, at California Polytechnic State University, in San Luis Obispo. With their bodies flattened into a disk, the rain beads up on their scales thanks to a microscopic, labyrinth-like texture that prevent the droplets from sliding off.
In 2017, Taylor and her colleague Scott Boback, of Dickinson College, in Pennsylvania, placed time-lapse cameras near wild rattlesnake nurseries in Colorado as part of a citizen science initiative called Project RattleCam. The images revealed that baby rattlesnakes assume the flattened position the day after they’re born. (Read how rattlesnakes have “friends.”)
“So they’re born thirsty, and they’re born with this instinct to do the rain-harvesting behavior,” Taylor says.
Of course, most animals can’t turn their bodies into a bowl at a moment’s notice. Here’s how some other creatures quench their thirst.
Thorny devils tap water with their skin
In Australia’s outback lives a lizard that looks more like a cactus. Known as thorny devils, these animals specialize in eating ants, which is also where they get a lot of their hydration.
But when ants are scarce, or conditions are even drier than normal, the reptiles have a backup. A network of tiny canals on their spiky skin catches small amounts of water and guides the liquid directly to their mouth.
What’s more, the devils can use the same trick to leech liquid out of moist sand after a rain or heavy dew. All they do is kick the sand up onto their back and let their skin do the rest.
An ocean away in southwestern Africa, the Namib desert beetle pulls off a similar feat.
Tiny bumps on the beetle’s back serve as a condensation site for moisture trapped in the morning fog. As more liquid beads up, the droplets grow in size until they run down the insect’s back toward its mouth.
Chimps use tools to scoop water
Chimpanzees may live in rainforests, but even in places with lots of moisture, it can sometimes be difficult to find a drink.
“Chimps, like many other animals, are a little hesitant to drink directly from big bodies of water,” says Cat Hobaiter, a primatologist at the University of Saint Andrews, in Scotland.
After all, rivers and lakes can harbor crocodiles, and puddles and mudholes can stagnate quickly. As a work-around, many chimpanzees in Central and West Africa make special tools, such as folding a leaf into a spoon, for extracting fresh rainwater caught in tree cavities. (Read how chimpanzee moms are so much like our own.)
“At the most basic level, you could pop your hand in and lick the water off, which they will sometimes do,” says Hobaiter, who studies chimps in Uganda’s Budongo Forest Reserve. “But using chewed-up leaves and moss as a kind of sponge is a much more efficient way to get that water.”
Some chimpanzees in Uganda have been observed using their hands to dig small wells in seemingly dry riverbeds. Elephants, coyotes, wild horses, and donkeys also dig for water, sometimes tunneling down as much as six feet.
Sandgrouse mop up water
Birds in the sandgrouse family, native to Africa and Asia, can’t build tools, but lucky for these pigeon relatives, they have mops built into their feathers.
In the cool of the morning, male sandgrouse fly up to 20 miles in search of water. After quenching their thirst, the birds dip their bellies into the pool, and their abdominal feathers soak up water. The waterlogged males then fly back to their ground nest, where their chicks use their beaks to scrape water from dad’s feathers.
Kangaroo rats of the U.S. Southwest take a different tack.
These pocket-size rodents survive in the desert on a diet of dry grass seeds and mesquite beans, which they pack into their cheeks and cache in underground burrows. Because the burrows are more humid than the surface, stored seeds may absorb as much as 30 percent more moisture than ones above-ground. So when the rodents eat their seed stash, they get both food and water. (Watch a kangaroo rat kick a rattlesnake in midair.)
Camels use their noses
Camels may be famous for making do in the desert, but it’s a common misperception that the ungulates keep water in their hump (or humps, depending on the species). Instead, the humps store energy-rich fat, which allows camels to go several months without eating.
But as desert animals, both camel species—the dromedary and the double-humped Bactrian—have a few other water-related strategies in their repertoire. For starters, when the animals do have a chance to drink, they can ingest upwards of 30 gallons of water at a time. In a pinch, Bactrian camels can survive on salt water. (Read how dromedary camels can eat spiky cacti.)
Camels also have evolved a nose that reduces the amount of moisture lost while breathing on chilly desert nights. A complex array of folds and ridges in their nasal passages creates more surface area for water to condense on the skin. This keeps moisture inside the body rather than expelling it out into the world.
Such water-saving adaptations may seem extreme, but in the desert, every drop can make the difference between life or death.