How Fast Do Fleas Multiply?

Life Stage 1 - Egg

Fleas go through four distinct life stages, starting as eggs. Although there is some variance in different flea species, female fleas typically begin to lay eggs two days after mating. A single female lays about 15 to 25 eggs a day. These eggs are deposited into the host animal's fur along with some feces. This feces is comprised almost entirely of digested blood and will feed the newborn when the egg hatches. Flea eggs are not connected to the host animal's hair and easily find their way into an bedding, carpet, spaces between floorboards and dirt.

Life Stage 2 - Larva

In 5 to 10 days the flea egg hatches, producing a larva. The larva feeds primarily on the feces deposited with the egg but can also survive on dead skin particles and other organic materials. One week after hatching the flea larva start spinning cocoons in preparation for their next life phase.

Life Stage 3 - Pupa

Once in the cocoon fleas enter the pupal stage. The pupa develop into adults in one week. If the weather is cold or other conditions exist that a flea would find undesirable, the developing pupa are able to slow down the development process to the point of almost stopping it. This allows the pupa to live undetected until more favorable conditions exist. This is the reason why some new homeowners suddenly find themselves infested with fleas come spring when the weather gets warmer.

Life Stage 4 - Adult

Pupa become adult fleas when they leave their cocoon. Adult fleas do not leave the pupa until they sense shadows, warmth, changes in air currents, the presence of carbon dioxide, or vibrations created by movement. All of these signs signal that a host is nearby. While fleas have a life expectancy anywhere from 15 to 99 days depending upon the species, adult fleas can survive without a host for only about 2 to 7 days.