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 functiοns 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.