What are the only mammals that lay eggs?
There are only a handful of mammals that lay eggs. These include the platypus, echidna, spiny anteater, and three species of duck-billed platypus. Interestingly, these egg-laying mammals all have different reproductive strategies. The platypus, for example, lays a single egg and incubates it for about two weeks. The echidna, on the other hand, lays eggs…