Why do spiny anteaters lay eggs even though they are mammals?

They lay eggs as most reptiles, but produce milk as mammals do. The word ‘monotreme’ itself means single opening. The reason is just as in reptiles, monotremes have only one single opening for fecal, urinary and reproductive discharge. read more

The egg-laying mammals — the monotremes, including the platypus and spiny anteaters — are eccentric relatives to the rest of mammals, which bear live young. In addition to laying eggs, other quirks make them seem more like reptiles than our kin. read more

Spiny anteaters, more properly known as echidnas, have eggs in order to ensure the continuity of their own kind. They are monotremes, which means that they are egg-laying mammals, like the platypus. They are classified as mammals because they have all the other characteristics of mammals. read more