Human flea

Fleas inhabit bedding, carpets, upholstery, animal resting areas, and sheltered cracks, with adults temporarily living on hosts.

Adults consume blood from mammals, including humans; larvae feed mainly on dried blood and organic debris in the environment.

Wingless, laterally flattened adults jump powerfully and move rapidly through hair or fibers. Eggs and larvae develop off-host, while adults emerge in response to warmth, movement, or carbon dioxide.

Bites cause itchy, inflamed papules and may trigger allergic dermatitis. Fleas can transmit pathogens, including *Bartonella* and some tapeworms; they have no meaningful human benefit.