The long-beaked echidna make up one of the two extant genera of echidnas, spiny monotremes that live in New Guinea. There are three living species and two extinct species in this genus. The extinct species were present in Australia. Echidnas are one of the two types of mammals that lay eggs, the other being the platypus. The echidnas retain reptilian features such as egg-laying but display mammalian features such as fur and lactation.