What Is the Average Life Span of a Flea?

Fleas live an average of eight days when they are on short-haired animals, and they stay alive longer on long-haired animals. Fleas that don't have animals to feed on live anywhere from a few days to two weeks.

Unhatched adult fleas can live in their cocoons for up to five months, which allows them to remain alive in apartments or houses even when the structures aren't occupied. Unhatched fleas emerge from their cocoons when they sense nearby movement of an animal or a human, and they can leave the cocoon and jump onto a host in just a few seconds.