The warmer the climate, the more we are destined to sweat. But while wet T-shirts can be uncomfortable, not all animals are lucky enough to sweat.
Mammals are the only species of animal with eccrine sweat glands, although these glands are sometimes used to help animals catch rather than cool themselves in the heat. In humans, horses, and some other mammals, these glands secrete a fluid that cools the skin as it evaporates.
As for the rest of the world’s mammals, reptiles, amphibians and birds, they must find creative ways to relax. Here are some of the unique processes animals use to keep their temperature from rising.
1. Take a lick
Credit: (Andrew Mulley/Shutterstock)
Kangaroos sweat like many other mammals, but with the scorching hot temperatures in some parts of Australia, they sometimes have to take matters into their own hands (or rather front paws). This is because marsupials lick that part of their body that contains several concentrated blood vessels. As their saliva evaporates, it lowers their blood temperature – cooling the animals in the process.
2. Avoid sand
(Credit: Chantel Bosch/Shutterstock)
Hot sand is a serious problem even for lizards adapted to life in the desert. Some Agamas have adapted to this problem by tiptoe across the surface of hot sand. When things get really hot, they can also burrow down to keep out of the sun. They are not the only species to do this; horned lizards and several types of snakes also burrow to cool or hide from predators and prey.
While the idea of sweating blood may seem appropriate for one of the deadliest mammals in Africa, the pink substance secreted by hippopotamus skin acts like any other sweat. Besides cooling large mammals in the heat, this pink sweat also repels insects and even water to somewhere. And to be fair, it’s not blood at all – although its pink color is still something of a mystery.
4. Get dirty
Contrary to popular saying, pigs don’t sweat like pigs. Instead, they rely on cool patches of mud or dirt to keep cool. Immersion in whatever foul liquid they can find often staves off the effects of the hot sun. And as the mud dries, it also acts as an insect repellent and sunscreenprotecting the pigs’ skin from harmful rays.
Many cold weather animals hibernate to survive the long cold winters. But other creatures use a type of long-term sleep called aestivation to get through extreme heat instead. If you’ve ever found snails that look burnt and shriveled on a hot summer day, they may actually be in this deep state of shutdown, with a slow metabolism to help them through dry spells. They are not the only creatures that use this technique. Reptiles, amphibians and lungfish also use estivation to prevent long periods of hot weather.
6. Take a leak
(Credit: минузиг/CC-BY-SA-4.0/Wikimedia Commons)
Birds may not sweat, but they use a different type of fluid to retain heat. Flamingos, some storks, and other long-legged birds urinate and defecate on their own feet to cool themselves—especially if they spend a lot of time on land in hot areas. The process is called urohidrosis. “Species that typically forage in open landscapes exhibit more pronounced use of urohidrosis than those that forage primarily in water bodies,” write the authors of research recently published in Scientific reports.
7. Open wide
For some, an alligator sitting on the bank of a marsh with its mouth wide open can be a terrifying sight. But crocodiles aren’t just waiting for something juicy to pop into their mouths. Rather, the act is closer to a dog’s panting—they probably use it to cool their body. And a recent study investigating this behavior found that while it can help cool parts of crocodiles’ bodies, cooling is not the only reason reptiles leave their mouths open. It can also send signals to other crocodiles nearby or, when underwater, be an invitation for risky fish to clean their teeth.