Platypuses are monotremes — the most primitive living mammals. They lack teats entirely; milk oozes through porous areolar skin patches on the mother's abdomen.
Platypus mammary glands are evolutionarily derived from apocrine sweat glands — representing the ancestral mammalian condition before teats evolved.
Hatchlings (called puggles) lap milk directly from the mother's fur where it pools. There is no nipple to latch onto — they simply lick the wet patch of belly fur.
Platypus milk contains a unique ring-shaped protein (MLP) with potent antibacterial properties. Without teats, milk is exposed to the environment, so this protein protects against contamination.
Thick and pinkish-tinged, with a faintly sweet, musky quality. Not sampled widely by humans due to the tiny quantities produced (~0.5 mL per expression). Consistency is similar to thin cream.
Very high in fat and protein to support rapidly growing hatchlings. Extremely low in carbohydrates. Calcium content is high (~200 mg/100g). Iron is elevated to compensate for the egg-based start to life, where yolk reserves deplete quickly.
Rich in iron and zinc. Contains high concentrations of lysozyme and other antimicrobial factors. Vitamin A and E levels are elevated. Mineral composition shifts significantly over the 3–4 month nursing period.
Contains monotreme lactation protein (MLP), a ring-shaped molecule not found in any other animal, with powerful antibiotic properties. Milk composition changes dramatically — early milk is dilute and watery, while late-stage milk becomes thick and fat-rich. Exposed delivery method (no teat) drove evolution of potent antimicrobials in the milk itself.