Echidnas, also known as spiny anteaters, belong to the family Tachyglossidae in the monotreme order of egg-laying mammals. There are four extant species, which, together with the platypus, are the only surviving members of that order and are the only extant
mammals that lay eggs.
Although their diet consists largely of ants and termites, they are no more closely related to the true anteaters of the Americas than to any other placental
mammal. They live in New Guinea and Australia. The echidnas are named after a monster in ancient Greek mythology.
Echidnas are small mammals covered with coarse hair and spines. Superficially, they resemble the anteaters of South America and other spiny mammals like hedgehogs and porcupines. They have snouts which have the functions of both mouth and nose. Their snouts are elongated and slender. Like the platypus, they are equipped with electrosensors, but while the platypus has 40,000 electroreceptors on its bill, the long-billed echidna has only 2,000, and the short-billed echidna which lives in a drier environment, has no more than 400 located at the tip of its snout.
They have very short, strong limbs with large claws and are powerful diggers. Echidnas have a tiny mouth and a toothless jaw. They feed by tearing open soft logs, anthills and the like, and use their long, sticky tongue, which protrudes from their snout, to collect their prey. The short-beaked echidna's diet consists largely of ants and termites, while the Zaglossus species typically eat worms and insect larvae