Of all the thousands of species of mammals, only three lay eggs. The two species of echidna and the platypus are the only egg-laying mammals (monotremes).Echidnas lay their egg directly into a pouch...
The only mammals which lay eggs are the small group known as monotremes. The smallest egg-laying mammal, or monotreme, is the platypus. The platypus weighs, at most, 1.7kg while the echidna can...
Placental mammals and marsupials do not lay eggs. Only monotremes are egg-laying mammals, and these include the platypus and the echidna. These mammals lay soft-shelled, leathery eggs.