According to the Encyclopaedia Britannica, sweat glands regulate body temperature by secreting water onto the surface of the skin where heat is then removed by evaporation. There are two types of sweat glands found only in mammals, the eccrine sweat glands and the apocrine sweat glands. The eccrine sweat glands are controlled by the sympathetic nervous system and are responsible for regulating body temperature.
When internal temperatures rise, the eccrine sweat glands secrete water onto the surface of the skin. Heat is then able to evaporate, allowing the body temperature to regulate. The Encyclopaedia Britannica states that animals such as humans, horses, and bears have active eccrine glands over most of their body which act as a major source for regulating their body temperature. In other animals, such as dogs and cats, the eccrine glands are only present in the paw pads or lip margins and may not be present anywhere else on the body. These animals mainly rely on panting to regulate their body temperature. Smaller animals, such as rodents, do not posses eccrine glands because they cannot endure dehydration.
Apocrine sweat glands are associated with hair follicles and continuously secrete fatty sweat into gland tubules. According to the Encyclopaedia Britannica, emotional stress causes the tubules to expand, expelling the fatty secretion onto the skin where local bacteria then break it down into odorous fatty acids. The apocrine sweat glands are located in the underarms and genital areas of human beings.