The Echidna, or Spiny Anteater, is a small Monotreme (egg-laying mammal) indigenous to New Guinea and Australia. They and the Platypus are the only monotremes still extant in the world. The Echidna is physically similar to both the Armadillo and the Hedgehog; it is covered in hair and spines and can curl into a tight ball when threatened. They are not true Anteaters, although they are related.
In its evolution, the Echidna split off from the Platypus and became a land-dwelling species, while the Platypus remained semi-aquatic; this was probably a reaction to the lack of water in many parts of Australia. The Echidna is nomadic and is found all over the Australian mainland. Dr. Matthew Phillips studied Echidnas using the "molecular clock" method and discovered that while they share ancestry with the Platypus, they continued to evolve to fit their ecologies while the Platypus remained virtually the same. The large number of predators and venomous creatures in Australia led to the formation of spines for defense, while their snouts developed to dig for ants and termites.