There are a small handful of basic things we deem necessary for life. Food, water and shelter are often considered the basic three and, in a pinch, you might just get away with food and water. And even then, if you had to choose between the two, water is the one you need most.
A human can only survive three or four days, at most, with no water. In extreme conditions this number can even reduce further. But for some animals in the world, dependence on water is barely a thing at all. Just the smallest amounts can keep all kinds of creatures going.
10. Freshwater Fish Don’t Drink Because Of How Salty They Are
You’ve probably heard the expression “drinks like a fish” in reference to someone who can pack away a lot of booze. On the surface it seems to make sense. What creature could possibly drink more water than a fish? They’re immersed in it all the time, they must constantly be pulling in the liquid, right? Not exactly.
Freshwater fish don’t actually drink water at all. As counterintuitive as it sounds, it’s true. That’s not to say they don’t absorb water, which they do through their skin and across their gills through osmosis. But it would be dangerous for a freshwater fish to actually drink water in the way humans and other animals do.
Because of the salinity of a fish’s bodily fluids they can’t ingest that freshwater without potentially killing themselves. Their kidneys would have to filter it incredibly fast or the fish would risk exploding thanks to the imbalance of salt in their blood and organs.
Instead, they use their gills to filter water to allow them to maintain the balance of salt in their body without risk to their health.
9. Mountain Gorillas Very Rarely Drink Water
Mountain gorillas are massive primates and can weigh as much as 400 pounds. Despite their bulk, the majority of the nutrients they eat comes from plants including leaves and stems, plus a small amount of roots, flowers, fruits and insects. They barely drink any water at all.
When it comes to moisture, they get what they need from succulent plants which can be neatly 50% water, as well as morning dew that may have accumulated on the plants as well.
Those who study gorillas and have done so for years have only noticed an increase in water drinking by the apes recently, arguably a result of climate change and increased temperatures in the natural habitat of the gorillas. Because it’s getting hotter the apes are more likely to feel the effects and risk dehydration if they aren’t supplementing their diets with actual sources of water.
Under ideal conditions, however, a mountain gorilla may never need to find a pool to quench its thirst.
8. Marine Mammals Get Most of Their Water From Their Prey
We already saw that fish aren’t big drinkers because they use their gills to get water through osmosis and that sounds great. But what about the mammals of the sea? Without gills, they’re just like the rest of us. They have to be drinking water, don’t they? Well, no, they found a workaround, too.
For the bulk of mammals in the sea, in particular cetaceans like whales and pinnipeds like seals, water is absorbed through what they eat. For whales in particular, metabolizing both protein and fat from the creatures they eat can often provide all the water they need to survive. In certain circumstances, however, it’s believed these mammals could supplement their diet with sea water if they are losing too much moisture because of evaporation.
Even tiny krill, which massive blue whales feed on, are able to provide enough water in most cases to keep the marine mammals going.
Incidentally sharks, though not mammals, are like some of their smaller cousins. That means they are saltier than the water in which they swim. As a result, they don’t drink water either and simply absorb water through osmosis as well.
7. Koalas Can Usually Get All the Water They Need While In Treetops
Koalas are like the unofficial ambassadors of Australia and everyone seems to love the cute little guys if for no other reason than they look cuddly and small. They’re also pretty remarkably little guys who have had a few hard years thanks to awful weather conditions down under.
Normally, a koala doesn’t need to drink water often at all. As hard as it is to believe, their very limited diet of eucalyptus leaves gives them some of what they need in terms of liquid. Or it used to, anyway. In addition, it’s been observed that they just lick water that runs down the trees during rain as well.
In recent years, soaring temperatures in Australia have driven koalas to the ground in search of new water sources. It’s more and more common to see videos and stories about koalas approaching people and seeming to beg for water from water bottles, which many people are happy to do.
6. Frogs Absorb Water on Their Skin
Frogs spend the bulk of their lives in the water but surprisingly enough they are not big drinkers. How they do stay hydrated can be more clever than you might think, though. Not all frogs just sit in a pond absorbing water through their skin, after all.
Green tree frogs in Australia make use of something referred to as “lemonade physics.” They will go outside in the cold for a while and then return to their warm tree home. Water condenses on their skin, like those inviting little beads of moisture on a glass of cold lemonade on a hot day. They can absorb that water into their flesh and it provides the hydration they need.
While not all frogs mimic glasses of lemonade, they are still designed for absorbing water rather than drinking it. Many frog species can sit in water and absorb it through patches of skin on their thighs and bellies that are known as drinking patches.
5. Kangaroo Rats Metabolize Water From Seeds
Most people aren’t big fans of rats due to that whole “brings of plague and death” thing they’re so often associated with. But not all rats are created equal. Take the kangaroo rat, for instance, which actually isn’t a rat at all but got stuck with the name.
You can find these creatures in the Sonoran desert and are so well adapted to desert life they literally never need to drink water in their entire lives. Their bodies are almost miraculous in the way they are able to extract water from things that humans would consider devoid of water entirely.
Kangaroo mice eat seeds which are not typically known for their juicy consistency. Despite this, the metabolism of these little animals is able to turn one gram of seed into a half gram of water. To further extend their own hydration their kidneys are able to super process urine to the point that what comes out is basically crystallized, ensuring no liquid goes to waste.
4. Thorny Devil Channel Water Out of Sand
Of all the desert dwellers who have unique adaptations for staying hydrated, few are as remarkable as the thorny devil. This intimidating looking little beast doesn’t drink water, and it doesn’t even need to absorb it through the food it eats, although they do seem to have the ability to absorb it through capillaries in their skin. The thorny devil is so good at hydrating itself where no water exists it just pulls it right out of sand and into its body.
In and among its many spikes and bumps, the thorny devil’s flesh is made up of microscopic grooves. When it’s touching sand that has even a trace of moisture, these grooves can pull the water from the sand. The water is then channeled along these little grooves into the lizard’s mouth, so its whole body is kind of like a bumpy, spiky straw. The deeper it immerses itself in slightly moist sand, the more liquid it can pull in.
Interestingly enough, the lizards couldn’t actually drink water if they wanted to. Their mouths have not adapted to licking water out of a puddle or stream and are essentially only useful for eating ants. So their method of drinking isn’t just unique and clever, it’s essential.
3. Naked Mole Rats Get Their Moisture From Roots
Naked mole rats are not known for being particularly attractive beasts though they do have a very cool name. They’re also well adapted to their environment and are tough and rugged animals to the point that scientists have noted that they almost never get cancer. But even beyond that, they almost never need to drink water.
Living underground, naked mole rats are prone to eating the parts of plants that also grow underground, chiefly roots and tubers. This is where they got their water from and the rats are smart about it. They only partially eat the roots so that the plant won’t die. That means it will continue to grow and provide a future meal for the mole rat at a later time.
2. Sand Cats Will Drink Water But Don’t Need To
How much do you know about sand cats? These broad faced but fairly small wild cats can be found in parts of Africa and Asia living, as their name suggests, in sandy, desert climates. It stands to reason that, as a desert species, they may have adapted to environments with little water and that’s very true of these small creatures.
At a maximum weight between three and about 7.5 pounds, these animals are smaller than most house cats though they do have dense hair that makes them look a little bigger than they truly are.
Life in the desert has allowed sand cats to adapt to weeks without a source of water. Like other predators they will simply take what they need from their prey, like adorable little vampire kittens. If water is available, they will drink it but otherwise prey animals like rodents, birds, even spiders and insects will get the job done.
1. Gerenuk Never Need to Drink
Gerenuks are slender, graceful animals whose name means “giraffe necked.” They’re a type of antelope found in Africa but they appear to be much smaller than most species. Their heads, in particular, are rather tiny which, combined with their large eyes and ears make them look almost cartoonish.
Like many animals of the savannah and hot climates it’s well adapted to life in a place where water is scarce. Unlike most of the animals the gerenuk has taken this adaptation to the next level. It’s possible for one of these animals to live its entire life having never tasted water.
They eat plants and their long legs and necks allow them to reach higher into branches to get more coverage. Their populations are also dense in the driest areas that many other animals can’t survive in for lack of water, ensuring that the gerenuk has plentiful food because of the lack of competition.
To help ensure they start hydrated they have evolved nasal passages that actually keep moisture in instead of allowing it to be lost to exhalation. Their urine is incredibly concentrate and they also live incredibly sedentary lifestyles so they’re not wasting energy or water unless they need to.