These animals can wedge themselves with their spines and feet into crevices and burrows in such a manner that it is practically impossible to dislodge them. With their long, sticky tongue, provided with mucus from enlarged salivary glands, echidnas feed on termites, ants, other insects, and worms. Some individuals have thrived when fed milk, finely minced meat, hard-boiled eggs, mealworms, and bread. The quantity of milk consumed by captives is remarkable. Echidnas have shown themselves able to exist without nourishment of any kind for at least a month.
Echidnas are generally solitary.
He concluded that echidnas seem to have a behavior that is not only simpler than that found in most mammals but perhaps also simpler than that of many lizards. During the breeding season females develop a temporary pouch on the abdomen. The single egg, or rarely two or three, is transferred directly from the cloaca into this pouch. When hatched, the young is naked and measures about 12 mm in length. It sucks the thick, yellowish milk that flows from the mammary glands, which open into the pouch.