Platypus: The egg-laying mammal once dismissed as a hoax

The platypus may be the least believable animal in the world: a duck's bill, an otter's body, a beaver's tail — and it lays eggs. When the first specimen reached Britain in 1799, scientists studied it and concluded someone had sewn a duck's bill onto a beaver: an elaborate hoax. Let's meet this "joke" nature played.

Its body

The platypus is a monotreme — one of the very few "egg-laying mammals". Its fur is thick and waterproof, its limbs webbed, and its tail broad and flat like a beaver's, perfect for swimming. Its bill looks like a duck's, but is really a soft electro-sensory organ: it is covered in tens of thousands of receptors that detect the faint electric fields given off by shrimps and aquatic insects in pitch-black water, pinpointing them precisely.

How it breeds

The mother platypus lays eggs and incubates them against her belly. When the young hatch they lap up milk that seeps through the mother's skin — platypuses have no teats, so the milk comes out through the skin. This is very different from most mammals and is a key feature of its status as a "primitive mammal".

What makes it special

The male platypus carries venomous spurs on its hind ankles, and a sting can cause weeks of severe pain in humans. In 2020 researchers also discovered that platypus fur glows blue-green under ultraviolet light — this animal seems to keep new surprises in store.

A note for grown-ups

You could talk with a child about how even scientists can be mistaken: back then the experts thought the platypus was fake. That teaches a child not to dismiss the incredible too quickly, but to test it with evidence — the true scientific attitude.