The rostrum is long, tubular, and tapering, and the lower jaw is represented by two slender bones. The mouth is small. Teeth are absent throughout life. The posterior part of the long, sticky tongue has horny serrations that work against hard ridges on the palate for grinding food. In other aspects, the blood of echidnas resembles that of other mammals.
Echidnas are powerful diggers.
An individual, in a horizontal position, can burrow straight down with remarkable speed. Shelters include hollow logs, cavities under roots or rocks, and burrows. 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.