Biology Fleas, as a group, are cosmopolitan in occurrence. They are commonly found in bedding or near areas where host animals sleep. They can spread through homes, buildings, and yards. Practically all warm-blooded animals are subject to attack by fleas. Each species of flea, however, usually feeds on a limited number of specific animals.
Flea bites cause a persistent, annoying itch.
Although some fleas, especially rat fleas, may transmit disease such as endemic typhus and bubonic plague, most fleas are not vectors. Fleas continue to feed and breed throughout the winter but often do so at reduced rates. Females mate and lay eggs on the host from which a blood meal is taken. Eggs typically fall off host animals and hatch in 2 to14 days. Outdoors in lawn areas or pet quarters, larvae generally feed on excrement from adult fleas, rodents, and domestic pets.