Fleas are small (2-3 mm), laterally flattened, wingless insects. They are renowned for their ability to jump prodigeous distances with specialised hind legs. Females require a blood meal before laying eggs. Some species only occur on specific hosts, while others have a wide host range. Females embed themselves into the skin of their hosts, while males are free-living in the environment.
Some flea species occur mainly on birds and small animals, others will attack large animals like warthogs and elephants. Some are voracious blood feeders, mostly associated with human dwellings and household pets. Fleas are mainly a nuisance through their itchy bites or ulcers, causing inflammation and discomfort, while others are vectors of plague and diseases.