Platypuses and echidnas are both monotremes. The name monotreme is derived from two Greek words meaning "one-holed", because they have just one external opening, the cloaca, for both waste...
A wallaby is one of any of about thirty species of macropod (Family Macropodidae). It is smaller than a kangaroo or wallaroo. It is actually a member of the kangaroo family, with its own distinct...