What if elephants had sweat glands after all?
If the elephant would have perspiratory glands, his skin would mostly be bathed in perspiration because an elephant weighing about 2000 kgs has a skin surface of roughly 112000 cm². A rat weighing 300 grams has a body surface of 300 cm². This means that in comparison with his weight, an elephant only has 1/18 of a rat´s body surface. Smaller creatures can therefore give away their body heat better than elephants and perspire much less.