How animals keep their cool

While we can break out the fans, iced drinks and air conditioning, animals have had to come up with more creative ways of coping when they start feeling the heat

 

We’ve had a scorcher of a summer, but most of us have at least been able to retreat indoors and stand next to the fridge when the heat’s been too much. Animals lack that luxury, but they’ve got their own ways of cooling down:

 

Getting sweaty

It’s our main method of thermoregulation when we get too hot, but sweating is rare in the animal kingdom

 

When we get too hot, we sweat. As the liquid evaporates from our skin heat energy is drawn away from our body. Some animals, like cats and dogs, sweat a little between the pads of their feet, but heavy perspiration is something we only share with monkeys, apes and horses.

A horse’s primary method for cooling down is panting, and its long nose makes it an efficient mechanism when it’s at rest or moving slowly. When it’s galloping at high speed, however, panting is no longer effective and it starts sweating.

It’s thought that sweating allowed early humans to become endurance hunters, just as it lets horses travel at high speed over long distances. While we perspire for the same reason, the composition of our sweat is different. Human sweat is almost entirely made of water and salt, but a horse’s sweat glands secrete a mixture of water, fats and proteins – this protein-rich recipe seems to help it lather and flow past the animal’s thick waterproof hair to the surface where it can evaporate.

 

Playing it by ear

Along with the elephant, several animals rely on their ears to help them keep their cool

An elephant’s ears are one of its most famous features, but they’re not just there for decoration. Jackrabbits, fennec foxes and elephants all have highly sensitive hearing, but thermoregulation is likely to be the main reason they evolved huge ears. These animals live in harsh climates, and their big ears provide a vital service in hot weather.

The large, thin areas of skin are full of blood vessels running close to the surface. If things start to get uncomfortably warm, the vessels dilate – muscles relax so blood flow near the surface increases, maximising the amount of heat lost from the blood to the air. This tactic is especially useful in the desert as it doesn’t cost any valuable water. Elephants waft their ears back and forth and spray them with water to enhance the effect.

 

Having a flutter

They might not have big ears to flap, but these birds have a neat trick up their sleeves – or rather, down their throats – when the weather is warm

For some birds, panting just isn’t enough; species including owls, doves, nightjars, pelicans and herons ramp up their efforts to stay cool with a tactic known as gular fluttering. Opening their mouths, the birds vibrate the muscles inside their throats. Similar to the flapping of an elephant’s ears, this movement exposes the moist membranes within to the air and encourages cooling by evaporation.

Although it might look like a lot of effort, the vibrations are small and don’t use much energy. For birds that roost in the open and are constantly exposed to sunlight and high temperatures, gular fluttering is a lifesaver.

 

For more cool animals, make sure to pick up your copy of Issue 62 of World of Animals.