The rat flea (Xenopsylla cheopis) is a small parasite that feeds on the blood of rodents. They are known carriers of a variety of diseases and are considered the main vector of bubonic plague. Infection is transmitted after a flea feeds from an infected rodent and then bites a human.
Rat fleas begin as white eggs, which drop from the female and hatch on the ground or are laid on the ground in the animals bedding. Emerging larvae are approximately 3 to 5 mm in length and appear similar to small, legless worms. Unlike adult rat fleas, larvae do not consume blood, but instead eat flea droppings, dead skin cells and animal hair. Larvae spin white, silken cocoons within which they pupate. After emerging from the pupae, rat fleas are capable of drawing blood and reproducing. Adults can live up one year and prefer to inhabit warm environments.
Adult rat fleas have two eyes but are only able to register light. The mouth of the rat flea is used to inject saliva and draw blood. Fleas are incapable of flight, but can jump up to 200 times the length of their bodies and 130 times their own height.