The typical lifespan of an adult flea ranges from two weeks to several months, depending on environmental conditions such as temperature, humidity, and access to food sources. On a host animal, fleas can survive for several weeks to several months, depending on the host's grooming habits, the severity of the infestation, and the species of flea. Flea larvae and pupae can also survive for several months in their cocoons, waiting for a suitable host to come along.