Fleas are external parasites which can be found attached to the skin of their hosts. Adult fleas measure approximately 1/8-inch in length. Their bodies are shiny and reddish-brown in color. They are covered with microscopic hair and are compressed to allow for easy movement through animal fur. Fleas do not have wings, although they are capable of jumping long distances. They have three sets of elongated legs. The cat flea is the most common flea, although dog, human, and sticktight fleas are also quite common. Fleas commonly attach themselves to dogs, cats, humans, chickens, rabbits, squirrels, rats, mice and other domesticated or wild animals. The female flea lays her eggs on the surface hair of the host. Eggs then drop from the host and can infest carpets, bedding and furniture, hatching into larvae within 14 days. Flea larvae avoid light and feed on organic matter found within cracks and crevices. Usually within 18 days, larvae enter the pupal stage by constructing small, cocoon-like structures around themselves. Approximately two weeks later, adult fleas emerge and begin to search for food sources. Fleas establish large populations where pets and other animals, such as livestock, are present. Multiple treatment methods are often employed to eradicate a flea population.
Pets suffering from flea bites scratch themselves incessantly. Fleas also feed on humans and some people exhibit flea allergies. Fleas may also carry human diseases such as typhus and tularemia.