They are sparsely covered with hairs. Pupae are enclosed in cocoons that become encrusted with soil particles and lint. They resemble tiny dust balls. The egg, larval, and pupal stages are rarely seen. Mating usually takes place on the host animal, but not always.
Female fleas mate only once.
They require a blood meal before they can lay fertile eggs, and not all eggs are laid at once. Since eggs are not glued or attached to the host, they can easily fall to the ground or to the nest or bedding of the host. A female can lay 4 to 8 eggs after each blood meal, and several hundred during her lifetime. Eggs hatch into larvae in 2 to 3 weeks. Larvae feed on organic debris such as hair and feathers, and especially the dried blood in feces of adult fleas.