4. Adult Fleas
Once a flea has emerged from the cocoon, it will need to begin feeding from a host within a few hours. Shortly after the first meal, adult fleas will breed and begin laying eggs within a few days. New adult fleas have a flat bodied appearance and are very small and dark in color. Once they feed, however, they will become larger and lighter in color, taking on the more recognizable flea shape. They spend the majority of their time living on the host while they feed, breed, and lay eggs, and can live anywhere from a couple of weeks to several months on the host animal.