Fleas are wingless insects (1/16 to 1/8-inch (1.5 to 3.3 mm long) and are agile, usually dark colored (ie, the reddish-brown of the cat flea), with tube-like mouth-parts to feed on the blood of their hosts. Fleas have long legs, the hind pair well adapted for jumping. A flea can jump vertically up to 7 inches (18 cm) and horizontally up to 13 inches (33 cm) making the flea one of the best jumpers of all known animals (relative to body size), second only to the froghopper.
Fleas lay tiny white oval-shaped eggs. The larva is small, pale, has bristles covering its worm-like body, lacks eyes, and has mouthparts for chewing. The larvae feed on organic matter, especially on the feces of mature fleas. The adult flea's diet consists only of fresh blood. In the pupa phase, the larva is enclosed in a silken debris-covered cocoon. New adult fleas live only about one week if a blood meal is not available. However, completely developed adult fleas can live for several months without eating, so long as they do not emerge from their puparia.
Optimum temperature for a flea's life cycle is 70°F to 85°F (21°C to 30°C) and optimum humidity is 70%. They are found everywhere, but the cat flea is the most common one found in the home and on pets. Adult fleas live on the blood of animals and must have it in order to produce young.
Fleas are brown colored, small insects that are laterally compressed,do not have wings and have piercing-sucking mouthparts. Flea infestations in homes usually become evident after a host animal (usually cats and dogs) have been removed. Fleas continue to develop from eggs previously laid and begin to bite people in the absence of normal hosts. A pest control specialist can treat the premises, while the pet should be treated by the owner or a veterinarian.