Kangaroos lick their forearms to survive heat.

While humans may enjoy lounging in front of a fan to cool down on a hot day, kangaroos lick their forearms to survive the sweltering temperatures of the Australian Outback. Though kangaroos have sweat glands, those glands only secrete sweat during active exercise, making them effectively useless for staying cool when the creatures are at rest. Instead, kangaroos rely on evaporative cooling — a process in which cool moisture from the animal’s mouth is absorbed directly into its bloodstream.

Kangaroos have a network of blood vessels located just beneath their forearm skin. Licking that area coats their arms with moisture, which is absorbed into those blood vessels, thus cooling the blood that flows through them. That cooler blood then circulates through the rest of the creature’s body, helping to lower its core temperature.