Flea Life Cycle: Understanding Fleas and Protecting Your Pet

Flea Life Cycle: Understanding Fleas and Protecting Your Pet

iStock_000002937031_MediumFleas can cause many problems for both your pet and your family. These troublesome parasites can cause skin irritations and transmit a number of harmful diseases, which is why regular, year-round treatment for fleas is highly advised for your pet.

First and foremost, though, it is important to be familiar with the life cycle of the flea in order to be effective at controlling or treating any flea infestations.

The life cycle of the flea consists of four stages: egg, larva, pupa, adult. Fleas are found throughout the country, and their total life cycle can range between a couple of weeks to several months. Ultimately, fleas thrive in environments where temperatures remain somewhere between 70-85°F, with a 70-percent humidity rate.


The flea life cycle begins when an adult female feeds off of your pet’s blood, which is a necessary step for an adult flea to reproduce. After the blood meal, the female will lay her eggs. Flea eggs are small, white objects (usually slightly smaller than a grain of sand) that are laid in your pet’s fur by a single adult female. She deposits the eggs in bunches of about 20, and can lay around 50 eggs every day.

The eggs are not sticky, unlike other parasite eggs, and fall off of your pet as he or she moves around the house and through the yard. This allows the eggs to be distributed throughout your pet’s and family’s living environment (i.e. carpets, bedding, soil, etc.), making it difficult to eradicate the parasites.

The eggs can take anywhere from two days to three weeks to hatch, depending on environmental factors such as temperature and humidity levels. The warmer the climate, the faster the eggs will hatch. Once the eggs have hatched, larvae emerge and the next stage of the flea life cycle begins.


Upon hatching, the flea larvae are blind and tend to avoid being out in the light. The size of flea larvae can vary according to climate and environment, but typically larvae are roughly ¼-inch in length and are virtually transparent. Although the larvae are legless, they do have small hairs along their bodies that allow them to actively move within any given environment.

The larvae continue to develop over the course of a several weeks, and feed off of pre-digested blood matter, called flea dirt, and other organic matter within the environment that other adult fleas pass along. Within 5-20 days of hatching, the larvae will then spin cocoons and pupate.


The pupae stage is the third and final stage of development for a flea before emerging as an adult. Wrapped in its cocoon, the pupae are protected for several days or weeks and will not emerge until conditions are right. The cocoon can remain intact for several months, and even years, if the environmental conditions are not right for emergence.

Unlike the eggs, flea cocoons have a sticky outer layer that allows them to remain hidden on your pet, and nearly impossible to remove from carpet or bedding during vacuuming or sweeping. The cocoon also protects the developing adult from any chemicals that are used in flea treatment or extermination.

The adult flea will only emerge from the pupa once it has identified a potential host by sensing body heat, raised levels of carbon dioxide, and vibrations which are all triggered by either your or your pet’s movements through the pupa’s environment. These changes in environment drive the flea to emerge from its cocoon to feed.

Adult Fleas

When the adult flea has emerged from the cocoon, it has an immediate need to begin feeding from a host. Adult fleas appear as small, dark pests with flat bodies, and become larger and lighter in color once they have begun feeding. An adult flea spends the majority of its time feeding and living on the host, with a lifespan of anywhere between two weeks to several months. It is only shortly after eating that an adult flea will breed and begin to lay eggs within a few days, and the whole life cycle begins again.

Flea Control and Prevention

Regular treatment is highly recommended for controlling and preventing flea infestations. Along with a preventative treatment for your pet, you should also consider products that will help treat your yard and home.

Contact us to discuss the various flea treatments that are available for your pet, and to determine which product is best for him or her based on the environment and risks your pet faces throughout the year.



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