A beagle puppy scratching its neck
A beagle puppy scratching its neck

Get the Facts About Fleas

What Are Fleas?

Fleas are tiny insects that can cause problems for your cats and dogs. These parasites feed on blood from host animals.To protect your cats and dogs, it ’s important to understand some basic facts about fleas. Where do fleas live and how do you spot them? What are the stages of the flea life cycle? What flea diseases are most common? Keep reading for some important flea facts and to learn why you need the proven assurance of the #1 name in flea and tick protection.1

Fleas Can Live Anywhere

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Fleas are found in all 50 states, but they flourish in the warmer climate of the southern US. Outside, fleas prefer shade and humidity. They typically live in crawl spaces, under bushes, in brush piles, and in sand. Dogs and cats can pick up fleas outdoors, as well as inside.

 

Where do fleas live once they come inside? It depends on the stage of the flea life cycle. Adult fleas—the ones you can see—make up only 5% of the population. Eggs can settle in your carpet or furniture. Larvae and pupae prefer dark spaces and might hunker down in the cracks in the floor, in your carpet, or in the cracks and crannies of your couch. And, of course, adult fleas are usually feeding on hosts, like dogs and cats.

fleas on carpet fiber
fleas on carpet fiber

Fleas Reproduce Fast

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Fleas multiply quickly, which makes them difficult to get rid of. How fast do fleas reproduce? One adult female flea can lay up to 50 eggs a day, producing hundreds of fleas over the course of a single month. Multiply that one adult flea by dozens, or even hundreds, and you can be faced with a big problem, because your home is likely already infested with thousands of eggs. This is why just killing the fleas you can see isn't enough—you need a product that kills adult fleas you don't see, and prevents their eggs and larvae from developing.

A flea on clothes
A flea on clothes

Fleas Need a Host to Lay Eggs

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Where do fleas lay eggs? All crucial parts of the flea life cycle—feeding, mating, and laying eggs—happen on a live host. On dogs, you’ll usually find the adult fleas around their hips or hindquarters. On cats, most fleas can be found near the neck. Because of their round shape and smooth exterior, the flea eggs slide off the host and become dispersed throughout the host's environment.

A cute dog lays on its back in the grass
A cute dog lays on its back in the grass

Fleas Are Hard to Spot

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Where do fleas lay eggs? All crucial parts of the flea life cycle—feeding, mating, and laying eggs—happen on a live host. On dogs, you’ll usually find the adult fleas around their hips or hindquarters. On cats, most fleas can be found near the neck. Because of their round shape and smooth exterior, the flea eggs slide off the host and become dispersed throughout the host's environment.

A dog runs with a tennis ball in its mouth
A dog runs with a tennis ball in its mouth. It's very cute.
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Flea life cycle moving from Flea Eggs to larvae to pupae to adult

The Flea Life Cycle

The adult fleas you spot make up 5% of the population—they represent just one out of the four stages in a flea life cycle. The other 95% consists of eggs, larvae, and pupae. The life cycle of fleas can last anywhere from two weeks to several months. The timeline is primarily dependent upon humidity, temperature and availability of hosts. The pupae spins a protective cocoon, allowing the flea to develop into a pre-emerge adult and bide its time until it senses the signs of the presence of a potential host (such as breath or vibrations).

The 4 Flea Life Stages

 

1. Flea Eggs: The flea life cycle begins when an adult lays eggs on a host. The eggs fall off and settle into the environment. It takes flea eggs 1 to 10 days to hatch, depending on the temperature and humidity of the surroundings.

 

2. Flea Larvae: The larvae, which hatch from the egg, are 1.5 to 5 mm in length. They remain in the larval stage for 5 to 15 days before spinning into a cocoon and pupating.

 

3. Flea Pupae: The pupae remain in cocoons they sense a host nearby. Because they don’t emerge until stimulated and they sense a host nearby. Because they don’t emerge until stimulated, fleas can remain in this stage for a few days to several months.

 

4. Adult Fleas: The adult fleas emerge from the cocoons and immediately find a host. Shortly after the first feeding, they will breed and start the flea life cycle over again. The entire flea life cycle can last anywhere from 12 to 174 days.

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Image of a tapeworm. Image credit: CDC

Fleas Can Spread Diseases to Your Pet

Flea bites can cause discomfort for your cat or dog. These parasites might even bite you or other family members, leaving you with sore bite marks on your arms and legs. But fleas are more than an annoying nuisance. What starts out as a simple itch can potentially lead to a wide range of skin conditions, flea-borne diseases, or other parasitic infections in dogs and cats. These include flea allergy dermatitis, flea anemia, Bartonella, or even tapeworm infections.*

 

*See individual product labels for indications.

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