Echidna

echidna, (family Tachyglossidae), also called spiny anteater, any of four species of peculiar egg-laying mammals from Australia, Tasmania, and New Guinea that eat and breathe through a bald tubular beak protruding from a dome-shaped body covered in spines. Echidnas have beady eyes and mere slits for ears, and at the end of their beaks are two small nares (or nostrils) and a tiny mouth. Electroreceptors in the skin of the beak may sense electrical signals produced by the muscles of invertebrate prey. Echidnas can be active day or night, probing along the ground slowly and deliberately as they search for prey, but they will shelter themselves from extreme midday heat in burrows or caves. Like their relative the platypus, echidnas have an unusually low but variable body temperature of 29–32 °C (84–90 °F) and cannot tolerate more extreme heat. In spite of echidnas’ outward resemblance to hedgehogs, the two animals are not related and belong to separate mammalian orders. Echidna species can be distinguished by their spines, by the number of claws on their feet, and by the shape and length of the beak.