Echidnas have spines covering their stout bodies. They curl up into a spine-covered ball in a rather effective method of defense. Echidnas are powerful diggers and can wedge themselves into a burrow or crevice with their spines so that they are difficult to remove. In general, echidnas dig for food, which consists of termites, ants, and assorted invertebrates. Food is located with the help of special electroreceptors located in the rostrum.
Echidnas have long, protrusible, mucous-covered tongues that aid in the capture of prey.
The sticky mucous coating is produced by enlarged submaxillary salivary glands. Spines at the base of the tongue grind against spiny ridges on the palate to masticate food. They have narrow, slender rostra , not at all expanded like that of the platypus . Their skeletons are heavily built, perhaps to accomodate the powerful muscles used for digging. Unlike platypuses, echidnas lack webbing and instead have large, shovel-like claws are present on all feet.