The adults may remain in the cocoons for up to five months, depending on the availability of a host and environmental conditions. They are dark reddish-brown to black. Their bodies are well adapted to their particular way of life. The mouthparts of adult fleas are adapted for puncturing animal skin and sucking up blood. Both male and female fleas bite and suck blood.
Adults have three pairs of legs, with the hind pair modified for jumping.
These powerful legs permit them to jump as far as 7 to 8 inches vertically and 14 to 16 inches horizontally. This ability may give the false impression that fleas can fly. They are wingless. The adult flea recognizes the presence of a potential host by the host's body heat and odor and by vibrations. This is one reason fleas often attack people returning home after vacation or when new occupants move into quarters formerly occupied by people with pets.