Echidnas are monotremes, or mammals that lay eggs. Two types of fur cover their body. A coat of short, coarse hair insulates echidnas from the cold, while longer hairs act as spines, protecting them from predators. Their sharp, creamy-colored spines are 50 mm (2 in.) in length and are composed of keratin, the same material that makes up our fingernails. Consuming ants, termites, grubs, larvae, and worms, the echidna is specially-adapted to hunt its prey. It has a pointy snout that can sense electrical signals from insect bodies.