NATIONAL MUSEUM OF NATURAL HISTORY

Five Wild Ways Animals Beat the Summer Heat

As we enter the dog days of August, learn how several animals stay cool


A small, tan fox with large, pointed pink ears blends into its sand-colored enclosure at the Smithsonian National Zoo.
As the world’s smallest species of fox living in the Sahara, fennec foxes utilize several adaptations to survive in such a harsh environment. One such trait is the immense size of their ears, which disperse heat and help them hear prey below the sand. Clyde Nishimura, FONZ Photo Club

Along with summer vacations and trips to the pool, August is known for its baking heat. Thankfully, us humans have a myriad of ways to keep cool, including sweating and air conditioning. But besides a few other animals like horses and hippos, most species cannot sweat, and next to none (save for some house pets) have access to air conditioning.

So, how do different animals beat the heat? Turns out they have some weird, clever, and sophisticated methods to keep cool when sweltering heat strikes.

Enormous ears

You may have noticed that some desert critters, like the fennec fox and jackrabbit, have massive ears. And this extravagant headgear is useful for more than better hearing – they also serve to keep these creatures cool by increasing the amount of heat radiating off their bodies.

This works because large, thin ears maximize the amount of surface area over a relatively small body mass. The greater the surface area, the more heat loss to the environment. That’s why it feels better to splay out in front of a fan on the hottest days and curl up into a ball on the coldest. Big-eared desert creatures harness this law of physics to stay cool.

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While most desert mammals are nocturnal and snooze through the hottest parts of the day, Cape ground squirrels prefer to do their foraging during the day. So these diurnal rodents use their bushy tails to shield them from an unforgiving sun, which is why they’re sometimes called fan-tailed squirrels. Bernard Dupont

Built-in parasols

Besides increased surface area, there are other cooling benefits to large appendages. Cape ground squirrels use their big bushy tails as a portable shield from the sun.

These squirrels, who are native to southern Africa, don’t live amongst tall, shady trees like the grey squirrels of DC, but rather in the sunny, baking climates of South Africa. The lack of tree cover means that these ground squirrels need to make their own shade – which is where a bushy tail comes in. Like carrying around a parasol, the squirrels will flip their fluffy tails over their heads to keep the baking sun from beating down onto them.

Heat-conducting hairs

Speaking of baking sun, Saharan silver ants live in heat that could literally cook them alive. But the ant’s cooling mechanism lies in their iconic hairdos.

The ant’s silvery shine comes from its dense coat of triangular hairs covering its exoskeleton. Scientists have studied these hairs and found that they play a powerful role in keeping these ants from frying. Not only do they reflect rays of light from the ant, the coat’s sophisticated structure helps dissipate heat away from the ant’s body – even under bright light. When studying Saharan silver ants, scientists found that shaved ants heated up under a lamp by over 10 degrees Fahrenheit more than their hairy counterparts.

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In addition to the cooling prowess, Saharan silver ants, like this Egyptian specimen in the Smithsonian’s collection, are also notable for their blistering speed. These tiny ants can run their body length in less than a hundredth of a second—which would be like a human running 400 miles per hour! Smithsonian Institution

Like hibernation, but for the heat

But what about when animals can’t keep themselves from frying in the heat? Some animals, like certain frogs and snails, need cool, moist conditions to survive. So, when heat strikes, they estivate! Estivation is like hibernation, but for hot, dry conditions rather than when it’s icy and cold.

Animals estivate by covering themselves in a crusty cocoon made of mucus to stay hydrated, but each species has a different plan for retreat to avoid becoming hot and crispy. Some animals, like the northern burrowing frog and the lungfish, head underground when their environment becomes arid. Others, like the common reed frog and heath snail, climb up onto vegetation to wait out the heatwave.

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When the weather heats up or dries out, several snail species, including the Eastern heath snail, hunker down in place in a dormant state and wait for cooler conditions. wallygrom

Practical patches

Giraffes are humungous creatures, which means that there are not a lot of available opportunities to add surface area. However, these tall animals have a sophisticated trick up their sleeve – or covering the rest of their bodies, for that matter. The giraffe’s iconic fur pattern is more than just stylish camouflage – it actually doubles as a built-in cooling system.

Underneath those colorful patches are complicated networks of blood vessels. When temperatures heat up, those vessels dilate, bringing more blood to the skin’s surface. This makes it easier for the towering animals to shed as much excess heat as possible.
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In addition to their dense clumps of blood vessels, researchers believe that the giraffe’s iconic long neck may help shade certain areas of its body from the savannah's sweltering sun. Smithsonian Institution

While we lack oversized ears, bushy tail fans or heat-wicking silver hairs, humans have developed our own ways of staying cool as temperatures skyrocket each summer. Whether you’re traveling or staying close to home, channel your inner snail by knowing when to head indoors to estivate in front of the AC!

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