Adult fleas are usually brown. They have strong legs adapted for jumping and piercing, as well as sucking mouth-parts. Their bodies are covered with backward projecting spines that help them move between the hairs on the host animal. Cat and dog fleas are usually found together and are similar in appearance.
Adult fleas live exclusively as parasites of warm-blooded animals. The females lay their eggs close to or on the infested animal. Wall-to-wall carpeting and soft furnishings also provide a relatively undisturbed environment for fleas to develop. They can also live in cracks and crevices in bare floors.