What are mammary glands?

Mammals have mammary glands. 

Mammary glands on a female mammal provide milk for her babies. This is called lactation.

Male mammals have undeveloped mammary glands that do not produce milk. 

Babies suckle the mammary glands. This is called nursing. 

The number of mammary glands depends on the species of mammal. 

Primates (monkeys and apes), goats, sheep, horses, and guinea pigs have 2 mammary glands. Humans have 2 mammary glands.

Cows have 4 mammary glands. They are called udders.

Cats have 8 mammary glands.

Dogs have 8 or 10 mammary glands.

Mice have 10 mammary glands.

Rats have 12 mammary glands.

Pigs have 18 mammary glands.

Photographer: Martina Nicolls

Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM