Fleas are blood-sucking insects that typically live on animals, but can also take up residence in your home in search of their next blood meal. Besides causing discomfort, these pests carry a variety of pathogens that cause disease. A flea infestation in your house is a serious problem that requires immediate attention.

To deepen your understanding of these wingless insects, we'll answer some of the most common questions about fleas, including:

What are fleas?

Fleas are small, blood-sucking parasites that generally prefer to feed on furred animals but will also feed on humans in a pinch. These small insects can't fly, but their long hind legs make them excellent jumpers. Although there are roughly 2,000 flea species throughout the world, only 325 of those species reside in the United States.

What do fleas look like?

Fleas are reddish-brown in color with flattened, oval-shaped bodies that allow these pests to move comfortably through their hosts' fur. Fleas usually don't grow larger than 1/8 inch. Fleas have six legs. Although they do not have wings, their hind legs are longer and jointed, giving them the ability to jump from host to host in search of their next meal.


Flea habitat and behavior

Fleas can survive in many different climates, but they prefer dark, humid, and warm areas. Outdoors, they like to settle on shrubbery and tall grass. Once they enter your home, fleas prefer to live in carpentry, upholstered furniture and bedding before latching onto a host to feed.

These pests don't sleep. However, they are least active during the day and more active at night. Since they are never fully inactive, females can lay eggs 24/7.

What do fleas eat?

Fleas are blood-sucking parasites. Their primary source of nourishment is animal blood. While fleas will feed on any warm-blooded mammal, they will often feed on animals since they can more easily hide in fur or hair.

Although blood is their main food source, fleas are omnivores. They will also eat feces, decaying plants, and even dead animal matter.

flea biting a human

Flea reproduction and life cycle

Depending on the environment, the entire flea life cycle can last between a few weeks to potentially up to one year. A flea needs a host in order to survive. Without one, it may only live about one to two weeks.

flea life cycle diagram

The life cycle of a flea consists of four stages:


Adult fleas find a safe place to mate and lay eggs. Usually, it's in the fur of a host. An adult female can lay up to 40 eggs a day. These eggs can take between two days and two weeks to develop.


Once hatched from the egg, flea larvae take several weeks to develop. At the larval stage, they are white, legless and almost invisible to the eye. In five to 20 days, larvae start spinning a cocoon.

Pupa (in a cocoon)

The pupa stage of a flea's life can last anywhere from several days to sometimes up to a year. The adult flea only emerges from a cocoon when it feels a viable host nearby. Otherwise, it stays inside its cocoon and waits for favorable conditions. Fleas are the hardest to exterminate while in the pupa stage.


Adult fleas start feeding within several hours after leaving the cocoon. Once they start feeding, they can start breeding – laying eggs within a few days after having fully matured.

How long do fleas live?

Fleas usually live for around 100 days, although, under optimal conditions, they can live for up to one year. In a single lifetime, a female flea can lay up to 2,000 eggs. Given that fleas can begin laying eggs within mere days after having become adults, they can reproduce rapidly and become quite a nuisance.

Common types of fleas in the U.S.

While there are more than 250 different flea species in the US, homeowners usually encounter only a few of them. The most common types of fleas include:

Cat Fleas (Ctenocephalides felis)

The primary host for cat fleas are house cats. However, they live on dogs as well. Cat fleas can live without food for months at a time. However, once they start feeding on blood, they can begin to lay eggs – up to 4,000 eggs on the fur of your pet throughout their lifetime. If you see your pet biting and scratching themselves frequently, this may be a sign they have cat fleas.

cat fleas

Dog Fleas (Ctenocephalides canis)

Dog fleas can most commonly be found on dogs, however, they may also bite humans. Ironically, over 95% of fleas reported on dogs are actually of the cat flea species. While cat fleas will source a meal from nearly any warm-blooded creature, dog fleas cannot survive on feline blood. Signs of dog fleas on dogs may include continuous biting and scratching, while in the rare instances where a human has been bitten by a dog flea, they will likely exhibit a rash with small bumps.

dog fleas

Human Fleas (Pulex irritans)

Sometimes known as the house flea, human fleas can live on humans and feed on other animals. They are extremely rare in the United States.

human fleas

Chigoe Fleas (Tunga penetrans)

This small flea burrows in the host's skin to lay its eggs. This flea is relatively rare and prefers tropical and subtropical climates.

Sticktight Fleas (Echidnophaga gallinacea)

The sticktight flea can sometimes be found on household pets, but is most commonly found on chickens and birds. This flea embeds its head under the host's skin, feeding on blood.

Rat Fleas (Xenopsylla cheopis)

Rat fleas, true to their name, feed on rodents. These pests are notorious for carrying a variety of pathogens that lead to diseases such as the bubonic plague and typhus. Rat fleas usually thrive in warmer, more tropical climates.

rat flea

Sand (Beach) Fleas (Emerita)

Sand fleas technically are not fleas. They're arthropods – similar to such crustaceans as crabs and shrimp. They live in the sand and feed on plankton.

sand flea

How do fleas spread and find hosts?

Fleas are avid travelers. They ride on their hosts and easily jump from one warm-blooded animal to another. Fleas find hosts by detecting body heat, movement, and vibrations caused by animal movement and breathing.

Can fleas fly?

No, fleas cannot fly. While fleas do not have wings, they do, however, have powerful hind legs that allow them to jump. Fleas can jump up to two feet into the air and leap forward as far as up to 200 times their own body length.

Can fleas live on humans?

The majority of flea species don't live on humans since they lack the perfect hiding and egg-laying attribute – fur. However, fleas can bite a human, have a blood meal for sustenance and move on to find a better living space.

Do fleas carry disease-causing pathogens?

Fleas can carry a variety of disease-causing pathogens. According to the CDC, the most common flea-spread diseases in the United States are the plague, flea-borne typhus, and cat scratch disease.

These pests can pick a disease-causing pathogen up from an animal or another human and spread it through saliva that they secrete into your bloodstream while feeding.

Are flea bites dangerous?

Since fleas can spread disease-causing pathogens, their bites are potentially dangerous if the flea is a carrier. In some cases, those diseases can be fatal. Some flea bites can also cause allergic reactions.

How to identify flea bites on humans and pets

It can be difficult to discern the type of insect that may have bitten you or your pet. By paying close attention, you can identify a flea bite.

Human flea bites

Human flea bites look like discolored bumps. They often appear in clusters or lines. Sometimes, bites can cause an allergic reaction, such as hives, itchy skin, or even breathlessness and swelling. In some cases, allergic reactions can result in fever, body aches and weakness among other signs.

Pet flea bites

It's tough to find flea bites on pets since their dense fur provides an ideal hiding spot for fleas. That's why it's important to look for other signs – such as scratching, hair loss, scabs, and irritated skin – on your pet.

How do you treat flea bites on humans and pets?

It can be difficult to discern the type of insect that may have bitten you or your pet. By paying close attention, you can identify a flea bite.

flea bites

Human flea bites

To treat flea bites, wash the affected area with antiseptic soap and water. If the area is itchy, you should consult your physician about applying over-the-counter anti-itch creams or taking antihistamines to reduce swelling. However, if you observe symptoms such as fever or body aches following a flea bite, it's recommended to visit your doctor.

Pet flea bites

If your pet has been bitten by fleas and is showing signs of dermatitis — which is an allergic reaction to flea saliva resulting in itchy, scaly skin and secondary infections due to intense scratching — it's important to visit your veterinarian. Your pet's vet can help you to come up with an effective treatment plan for flea bites. In the meantime, a cool bath can reduce the symptoms of a flea bite and make your pet more comfortable.

How to tell fleas and bed bugs apart

Although both fleas and bed bugs are reddish-brown in color, there are a few key differences between the two. Bed bugs are flat and oval-shaped while fleas are more narrow and flattened. Bed bugs crawl slowly, while fleas are quick jumpers that can hop almost 200 times their body length.

How to tell fleas and ticks apart

While fleas and ticks are often lumped together as common pests that latch onto pets and feed on blood, there are some very visible differences between the two. When comparing fleas vs ticks, ticks are teardrop-shaped and black, while fleas are narrow, long, and brown. Ticks are comparatively larger than fleas. Another key difference is that when ticks feed, their bodies become engorged with blood, swelling in size. Ticks remain on the host for several days while fleas jump off their host right after feeding.

Why are fleas in my house all of a sudden?

Fleas often may come into your home while riding a pet or clinging to the grass on the soles of your shoes. If your home is appealing enough (warm, humid, and with ample opportunity to feed), fleas can stay in your home and reproduce. Fleas inside a home may also be a possible indicator of an unknown rodent or wildlife problem.

How can I prevent a flea infestation?

To prevent a flea infestation, you need to make your home and yard unappealing to these pests. Here are a few tips to follow to prevent a flea infestation.

Home prevention

Homeowners can take preventive actions within the home in order to keep fleas at bay and prevent an infestation.

  • Vacuum regularly and pay special attention to carpets and rugs
  • Empty vacuum bags.
  • Clean the bedding, including pet beds, frequently.
  • Ensure proper ventilation.
  • Remove garbage and clutter regularly.
  • Yard prevention

Yard prevention

Conducting regular outdoor maintenance can help reduce your risk of fleas taking up residence in your yard.

  • Mow the lawn.
  • Trim back shrubs.
  • Keep animals away from your yard.
  • Wear an insect repellent containing DEET while outdoors

Pet care

Pets are part of the family and they spend a great deal of time indoors as well as outdoors. This not only puts them at risk of picking up fleas after a good roll in the grass, but also means they can track them into your home. Here are a few tips to help protect your four-legged family members from fleas:

  • Regularly apply veterinarian-approved treatments for fleas as directed by your vet.
  • Wash pets regularly and use flea combs.
  • Don't miss regular vet appointments.

How do I get rid of fleas in my house?

You can try to get rid of fleas by using a power vacuum, steam cleaning carpets, and washing all the bedding. Calling on a pest professional can help you rid your home of fleas and help ensure they stay away, especially in more challenging situations.

Benefits of choosing Terminix® for your flea control

The pest control specialists from Terminix are well-versed in a variety of effective techniques to help get rid of all fleas in your home, regardless of their lifecycle stage.

Don't waste time on DIY efforts. Contact us for a free inspection today!