Fleas are laterally compressed wingless insects. The wingless condition has been an adaptation to the parasitic life since the wings can get tangled in the host's hair. Fleas have strong jointed legs. Fleas can jump the equivalent of a man jumping 1000 feet. They can tolerate frozen temperatures and enormous pressure.
Most species are variably host specific.
The remaining population had the human flea, Pulex irritans . Ctenocephalides canis was not found. The most common species in animals are 1. Ctenocephalides felis is the most common flea in dogs and cats but it is not strongly host specific. However it seems that human blood is not complete enough to allow reproduction and completion of the life cycle.