How Long Do Fleas Live? What To Know About the Life Cycle of Fleas

Have you spotted a single flea on your furry friend? Have you seen a few? Trying to prevent or resolve a full-blown flea infestation can feel like an uphill battle. No matter whether they’re inhabiting your pet’s fluff or hiding out deep in the cracks of your flooring, fleas can lay up to 50 (!) eggs a day and multiply in a jiffy. And while warmer months may provide more favorable conditions for these unwelcome visitors to thrive, the reality is that they can survive any time of the year.

But how long do fleas live? And how can we successfully disrupt the life cycle of fleas and eliminate them from our homes? We spoke with two veterinarians to get the facts on these pesky pests.

Fleas must go through a complete metamorphosis that involves four distinct life stages: egg, larva, pupa, and adult, says Amy Attas, VMD, founder of City Pets Vets, in Manhattan, New York, and author of “Pets and the City: True Tales of a Manhattan House Call Veterinarian.”

Dr. Attas stresses that understanding the life cycle of the flea is crucial for effective control and prevention. The best flea control, she says, uses interventions that target multiple stages of the flea life cycle.

Dr. Attas breaks down the four flea life cycle stages:

The tricky part about flea eggs is that they’re smaller than a grain of sand. This makes them hard to see with the naked eye. Not to mention, they can easily be mistaken for something else, like sand, salt, or dead skin, due to their small size and pale appearance.

Dr. Attas describes flea eggs as being very tiny, oval shaped, and off-white in color. “Eggs are typically laid on a mammal and then fall off into the environment and will be highest in numbers where the animal sleeps,” she says.

So, whether your kitty enjoys taking cat naps on your bed or your dog prefers to snooze on the couch, there’s a good chance that eggs are there. Because they’re eggs, Dr. Attas says they don’t feed. They can remain in the environment for two to 10 days depending on the temperature and humidity, she adds.

After spending anywhere from a few days to a week and a half in the environment, flea eggs hatch into larvae. At this stage, flea larvae are small (2–5 mm), hairy, translucent, and worm-like, Dr. Attas says.

If their physical description alone didn’t give us the heebie-jeebies, the fact that they live in dark, moist places in the environment, like your pet’s bedding, is enough to keep us up at night. In this type of environment, Dr. Attas says larvae feed on organic debris, particularly flea dirt—aka flea feces.

Depending on temperature and humidity, this stage of the flea life cycle can last anywhere from five to 20 days.

When fleas are in their larva stage, they produce silk from their salivary glands and spin a silken cocoon around themselves, Dr. Attas explains. When they’ve finished making their cocoon, they begin their metamorphosis process and transform into a pupa, which is about 5 mm. Fleas in the pupal stage don’t eat.

The cocoon is sticky and catches debris, which helps it camouflage into the environment, Dr. Attas says. The pupa stage can last up to several months. The reason for this is because during this time, the pupa’s cocoon protects it from insecticides, repellents, and other environmental conditions. Dr. Attas says pupae will emerge from their cocoons once they detect favorable environmental conditions and the presence of a potential host (with body heat, increased levels of carbon dioxide, and vibrations).

When the flea pupa is inside the cocoon, Dr. Attas explains, it undergoes yet another metamorphosis into their final life cycle stage—an adult flea. Its former larval tissues break down and reorganize to form adult flea structures, such as legs, antennae, and mouthparts, she says.

Adult fleas are 1.5–3 mm long, flat, dark brown, and have a flattened body and legs adapted for jumping, Dr. Attas notes. And boy, can they jump! Fleas are able to jump up to 7 inches high by 13 inches horizontally. This makes it easy for them to make their way onto your pet or your ankles.

Adult fleas need a food supply to survive. This means they’ll bite dogs, cats, wild animals—and even us if they’ve been brought into our environment on our pets and hopped off. “They live on their hosts, where they feed, mate, lay eggs, and defecate,” Dr. Attas says. “They can be found in the environment as well but need a local host to survive.”

Male and female fleas feed in the same manner, she notes. The only difference is that the male fleas feed for their survival, whereas female fleas need a blood meal for egg production.

According to the U.S. Centers for Disease Control and Prevention (CDC), it takes only a few hours for an adult female flea to begin feeding on a host animal once they’ve emerged from their cocoon. It’s not long before they mate, and the flea cycle continues.

The length of the flea life cycle duration varies depending on the temperature and humidity in the environment, Dr. Attas says.

It can take about three weeks on average but up to several months for the process to be completed. In the right conditions, meaning when they have a suitable host to feed and live upon, adult fleas can live for about three months.

So, how do you know if that was, in fact, a flea in your home and not a springtail or bedbug?

Fleas are tiny, wingless insects with a flattened body that makes moving through their host’s fur easier, says Sabrina Kong, DVM, certified canine rehabilitation practitioner at Jules Veterinary Center, in Tracy, California.

They can appear to be dark brown, or reddish-brown after a blood meal, and measure about 1.5–3 mm in length with long hind legs, she adds.

It can be challenging going up against who knows how many fleas. Our veterinary experts recommend the following multi-step approach for getting rid of fleas on dogs and cats, as well as in the home:

• Use a veterinarian-recommended flea and tick treatment for pets. Treatment options include topical solutions, oral medications, or flea collars. Your veterinarian will determine the best flea and tick treatment for your pet.
• Thoroughly clean the home environment. This includes frequently vacuuming carpets, furniture, and pet bedding weekly until no fleas are present. When you’ve finished vacuuming, Dr. Attas advises removing the vacuum bag outside and placing it in a sealed plastic bag and wiping down the vacuum as well. It’s also important to wash your pet’s bedding and anything else they sleep on or spend time in hot water.
• Use a household flea spray or fogger. (In cases of severe infestations.)

“The process of eradicating fleas can take several weeks to a few months, as it involves breaking the flea life cycle, which includes eggs, larvae, pupae, and adults,” Dr. Kong says.

Not only can flea bites cause your pet discomfort, but they can also cause problems like skin issues, allergies, anemia, and tapeworm infections. Some species can even transmit the plague (Yersinia pestis).

The best way to prevent fleas on your canine or feline companion is by regularly using a monthly preventive year-round. There are several types of treatments to choose from. Give all pets in the household parasite preventives, even if they’re an indoor-only pet; and make sure that flea treatments for cats and dogs are only used for the intended pet (i.e., never use a flea treatment made for dogs on cats, and vice versa). Again, use a preventive recommended by your vet.

Keeping your home clean is also important. That includes vacuuming regularly and washing pet bedding frequently, Dr. Kong says. “Keeping pets away from flea-infested areas and periodically checking for fleas, especially after spending time outdoors, can help prevent infestations.”

A few examples of flea-infested areas include locations with tall grass and wood piles, areas where wildlife may have recently been, dog parks, and dog daycare, Dr. Attas notes.

When it comes to flea prevention, consistency is key. Even missing just one month of flea and tick treatment can give opportunistic, hungry fleas a chance to feast on your pet and potentially become a big problem.

If you find yourself dealing with an infestation, regularly treat your pet with a preventive, vacuum your home, and wash your pet’s beddings and toys with hot water. Eradicating fleas takes patience and effort, but it is possible. Both you and your best furry friend will be thrilled to have a flea-free home! Next, learn more about flea season.

Expert input provided by Amy Attas, VMD, founder of City Pets Vets, in Manhattan, New York, and author of “Pets and the City: True Tales of a Manhattan House Call Veterinarian”; and Sabrina Kong, DVM, certified canine rehabilitation practitioner at Jules Veterinary Center, in Tracy, California.

This content was medically reviewed by Chewy vets.