Females lay 4-8 eggs after each blood meal, laying some 400-500 during their lifetime. They usually hatch in 1-12 days. The pre-emerged adult remains in the cocoon for up to 20 weeks, where it is protected from adverse conditions, including pesticides. Adults are stimulated to emerge from the cocoon by mechanical depression for the cocoon, an increase in temperature, and possibly vibrations. Larvae and pupae are typically found where the animals sleeps or frequents. Adults usually begin to seek a blood meal on the second day after emergence, but can live for several months on stored body fat. Cat fleas may transmit plague. There is very strong circumstantial evidence that they may transmit murine typhus.
Cat fleas serve as intermediate hosts of the dog tapeworm. These tapeworms occasionally infest humans, especially very young children. The dog tapeworm commonly infests cats that spend time outdoors. Fleas are typically found where animals sleep or frequent, including along their usual avenue of travel, because this is where eggs and adult fecal bolld accumulate. Cat fleas are also found on other urban hosts such as opossum, fox, mongoose, and occasionally rats.