It is a common mistake to confound the definitions of cutaneous evaporation with perspiration (sweat rate). Birds have no sweat glands, while pigs have a limited number in the surface of the body, which are not responsive to thermal stimuli. Cutaneous evaporation can occur through insensible perspiration due to the permeability of the epidermis to the passage of liquids from inside the body (Da Silva and Maia 2013). Around 50 % of total evaporation occurs via insensible perspiration in some birds when exposed to high temperatures (Lasiewski et al. 1971). Sweat rate is the secretion of a liquid (sweat) by specialised cells. Animals that have sweat glands (cattle, sheep, goats) present both insensible perspiration and perspiration.