Is there a mammal that lays eggs

The Platypus

�

Q� Why are they classified as mammals if they lay eggs

A� Animals are classified into groups based on a suite of shared, significant features. To read more on classification, click here.

�

Mammals are warm blooded, have hair, have a single jawbone, three inner bones, and a high metabolic rate and, of course, suckle their young using their mammary gland. They also give birth to live young, and this is where the monotremes differ from other mammals, but it is the only difference and so biologists classify them in this group because they share all the other relevant features.

�

Monotremes still hatch eggs, a reminder of the shared evolutionary past of mammals, reptiles and birds.

�

Q� Where do Monotremes live

A� They're found only in Australia and New Guinea.

�

Q� How do monotremes give birth

A� Echidnas carry the egg in a pouch, where it hatches. Then the barely developed youngster has to find and latch onto the mammary gland.

�

Very little is known about the nursing habits of the platypus because it lays its eggs in a burrow, out of view from humans.

�

Q� Do they have any other un-mammal like qualities

A.� Yes, the platypus is unusual among mammals in that it's venomous. The males use the venom, secreted in spurs on their hind legs, when competing for females. Although the venom isn't potent enough to kill a human, some dogs haven't been as�lucky.

�

Is there a biological conundrum you'd like to ask a question about

�

by Lisa Cardy