Rule Breakers of the Animal World

Kiwi

The kiwi is a flightless bird that is nocturnal (active at night). Its shaggy feathers look like hair, and its whiskers help it navigate in the dark. With muscular legs and a lower body temperature than most birds, the kiwi is sometimes called an honorary mammal.

Moonfish

Most fish are cold-blooded, but not the moonfish. It’s the only known fully warm-blooded fish. It lives deep in oceans around the world. In these cold waters, the moonfish survives thanks to heated blood that circulates through its body.

Peterwchen, CC BY-SA 4.0, via Wikimedia Commons

Pacific Beetle Cockroach

Though most cockroaches lay eggs, this beetle cockroach gives birth to live young. The mother Pacific beetle cockroach also produces a nutritious “milk” for her babies.

Pangolin

The pangolin is the only mammal completely covered in scales. This suit of armor protects it from predators in a fallen world. The pangolin also defends itself by lashing out at predators with its sharp-scaled tail or curling up into a tight ball when threatened.

Echidna

Mammals give birth to live young—at least, most of them do. Monotremes (MAH-no-treems) are mammals that lay eggs, like four species of echidna (eh-KID-nuh) in Australia. The female echidna lays soft-shelled eggs that are about the size of grapes. Baby echidnas are called puggles.