by Kim Doner
Horses sweat. Men perspire. Ladies glow. (Yeah. Right.)
So where does that leave the rest of the animal kingdom when things heat up?
I’m so glad you asked!
Sweat glands are handy things that release water from our systems to evaporate and cool us, but not every creature owns a set. Most pets, such as dogs and cats, pant by opening their mouths, exposing as many square inches of mucous membranes as possible. However, other species cope with summertime differently — some through evolution, some through behavior, and some through community.
Underground prairie-dog villages are a maze of tunnels, but if one knows where to look, there will be small, open “towers” of earth strategically placed. Those mounds will catch a breeze and channel it into the burrows, flushing out hot air and lowering the temperature for the residents.
Aboveground, squirrels will “sploot,” stretching their bellies as far as possible against cooler surfaces. This is known as “heat dumping” and can be observed in other species — notably, koala bears, who will spread-eagle against a heavy tree trunk so the bark allows cooler air to flow across their tummies.
Another notable Australian animal is the red kangaroo, which has quite a solution for desert days. They spit on and lick their forearms until the fur is soaked. As the saliva evaporates, the blood vessels near the surface send cooled blood back into their bodies for quick relief.
I do not recommend doing this publicly. That’s only for red kangaroos.
The last of the Land Down Under “cooler critters” is the echidna. Monotremes, or egg-laying mammals, they are found throughout Australia, Tasmania, and New Guinea in all climates. They have weird, tunnelish snouts — or beaks — that are very vascular. To cool this blood, they blow snot bubbles out the tip of their beaks and hope for a breeze.
Again, don’t do that publicly either.
African Adventures
Next, take a look at African animals —rhinos, for instance. The plates of skin on their body are superthick, which shield them in many ways, but if you look inside the folds, the skin is much thinner and more sensitive. (Word has it that tame rhinos like scratches there, but I have yet to try.) Swimming helps water reach that thin skin to achieve lower body temps.
Hippos, though, are already in water, right? What they’ve figured out — and pigs of all varieties do this too — is how well a solid mud bath works. By coating the skin, the drying mud steadily carries away body heat. The plus is that the animals can meander anywhere postmudding and then waddle back into the water once they feel toasty.
But hippos have yet another superpower! They secrete a pinkish, sweatlike liquid that not only cools them but repels insects. Why it’s pink is something of a mystery because it’s not blood — and it’s fairly waterproof. Maybe it’s hippos that glow.
Although hippos and rhinos have found solutions to heat via physical structure and habitat, giraffes have evolved specialized skin. Their patterned coats consist of dark patches with channels of lighter tan around them. As the animal heats up, blood migrates to the outer edge of the dark patches and into the lighter channels, where heat is released from the body.
Another heat-resistant ungulate is the camel. Camel fur is much thicker on top. It’s dense and fluffy, so it works much like insulation from the sun. And the fur on their bellies is pale and fine, allowing their bodies to flush warmth away when they need to.
You might ask what elephants and hares have in common. They differ quite a bit, but look at the ears on those guys — large, heavily veined, and thin-skinned. Lifting or perking or flapping those appendages allows airflow. Elephants are especially adept at inhaling and blowing water across their ears as an added bonus.
Avian Adaptations
But what about our feathered friends? Birds have their own styles of beating a heat wave. Storks and vultures will poop down the backs of their legs, which allows the matter to dry and cool them, much like the mud bath a hippo might use. Less repellent is “gular fluttering,” used by (most notably) owls, herons, and pelicans. The bird might or might not have its beak open, but it will rapidly vibrate the muscles and bones in the throat as air is pulled over and through the mouth. In some birds, no sound occurs, but for the shoebill stork, it’s like a machine gun going off.
Oddly, this act uses very little energy, which I’m sure is a plus during an oppressively hot day.
Future Outlook
Sadly, our wild friends will have to scramble as climate change continues to cook the earth. Wildlife IS responding to the heat, faster than most evolutionary steps but slower than the climb. Several species of Australian parrots have shown as much as a 10 percent increase in bill size in the past 150 years, correlating with the rising temperatures. The larger the bill, the more surface area to cool the bird. Let’s hope.
This kind of shape-shifting will make a stressful demand on the animal kingdom, with surviving species adapting through, perhaps, larger ears? Bigger wings? Longer tails? Migration, estivation (when an animal becomes torpid from heat), a whole lot of luck?
Maybe it’s time for us humans to cool it too.
