Fleas are a nuisance to the existence of dogs and cats. First, you need to know a few things about flea biology. Adult fleas live on pets and lay eggs only when they are on animals.
Eggs fall off pets and hatch into larvae.
Larvae may crawl several inches to avoid light. Larvae develop into pupae and are protected by a cocoon which makes this stage the most difficult to eliminate. An effective flea-control program eliminates adult fleas on pets and recently emerged adults and immature stages in the environment. While adult fleas reside on the host, the immature stages and newly emerged adults are in the pets environment. Treating the pets environment is the most important step, yet it is usually the one most often overlooked.