Evaporative Heat Loss

If an organism’s body is at a higher temperature than the surrounding environment, then evaporation is the only mechanism of heat exchange through which the animal can lose heat and stabilise back to internal physiological temperature.

Have you ever wondered why you’re so much colder when you turn the water off after a shower? This is because evaporation is a powerful mechanism for losing heat. For every gram of water that evaporates from you, you “lose” approximately 2.4 kJ of heat. This process is known as evaporative heat loss. Animals often use evaporative strategies, such as panting and sweating, to discard excess heat.

However, if the surrounding environment is extremely hot or if the animal becomes short on water, extended evaporative heat loss can lead to dehydration and hyperthermia, where the body temperature begins to rise to excessive levels. With wind, a higher amount of evaporation occurs due to the increased flow of air in contact with the animal's skin.