Fleas are pests of humans and their domestic animals all over the world. While most fleas prefer non-human hosts, many can and do feed readily on humans when infestations are heavy or when other hosts are not readily available. Fleas are small, wingless insects, which average 1/12 to 1/6 inch long but can vary from as small as 1/25 to 1/3 inch long. When viewed from the front, head on, the flea's body is narrow from side to side. This allows them to move readily between hairs in an animal's fur, in the nap of carpeting and into very narrow areas such as crevices and folds in upholstery, or even below flooring and into sub-flooring areas. Their bodies are also covered with spines, which project backward, making them well adapted for moving forward between the hairs of feathers of the host body. These same spines make the removal of the fleas, by shaking or scratching rather difficult. Fleas have piercing, sucking mouthparts to penetrate the skin of the host and suck blood. Their long powerful legs permit them to jump as much as 7 to 8 inches vertically and 14 to 16 inches horizontally. These considerations should be kept in mind when flea management programs are planned. A female flea will lay a few eggs each day until she has laid 200 to 400 eggs. Depending on the temperature and humidity, these eggs will hatch in anywhere from 2 days to several weeks, but most will hatch within 7 to 14 days. Fleas feeding undisturbed may live up to 3 weeks on a host. The two most common species are the cat and dog fleas- cat fleas are the most common of all, while dog fleas are more commonly found on wild host, rather than on domestic animals. They prefer locations where dust and organic debris accumulate, and are commonly found in houses, under buildings, and, if temperature and humidity permits, in yards. Both are intermediate hosts of the dog tapeworm, which is common in both cats and dogs. When playing near infected pets, children can become infected with this tapeworm by accidental ingestion of infested fleas.