Milk without a nipple
A platypus makes milk in mammary glands, as other mammals do, but it has no nipples to deliver it. Instead, the milk passes through tiny openings in two milk-producing areas of skin on the mother’s abdomen. It is not sweat: the glands release milk directly onto the skin, where the coat can hold it in shallow grooves.
A nursing surface in the nest
After hatching, the young stay with their mother in a nest inside a burrow. When they need to feed, they press and lick at her fur, taking in milk that has collected there. This works because the mother remains close to her offspring in the enclosed nest; the young do not need to find or latch onto a teat.
The arrangement is unusual, but it serves the same essential purpose as nursing in other mammals: delivering a mother’s milk to her young. Platypuses belong to the monotremes, the small group of mammals that lay eggs. Their young hatch from eggs, then rely on milk as they grow—a reminder that mammalian milk does not require nipples, even though most mammals use them.
