“The mammary glands of cows, sheep, goats, deer, camel, horses, and even whales are located in the inguinal region; those of primates and elephants are in the thoracic region, but those of pigs, rodents, and carnivores are along the ventral surface of the thorax and abdomen. The mammary gland, as with sebaceous and sweat glands, is a cutaneous gland. Milk is formed by synthesis and diffusion processes from the blood in the mammary gland.”