The echidna: a spiny, egg-laying mammal
Echidnas, together with platypuses, belong to the monotremes, mammals that lay eggs. Like other mammals, they feed their young milk, but they have no nipples: milk is secreted through pores on specialized milk patches of skin, where the young lick it up.
Illustration is AI-generated and conceptual, not documentary photography.
Their spines are modified hairs and provide protection. An echidna can curl up with its spines facing outward. Eggs, milk, and spines make it unusual, but it is very much a mammal.