The two known monotremes are the platypus and the echidna, of which there are two species, the short-beaked echidna of Australia and the long-beaked echidna of New Guinea.
The two monotremes are the platypus and the echidna. There is just one species of platypus, and two species of echidna - the long-beaked echidna, found in New Guinea, and the short-beaked echidna,...