There are an estimated 300 species of fleas in the United States, with the most common domestic flea being the cat flea or Ctenocephalides felis. Other common types of fleas include dog fleas (Ctenocephalides canis), rat fleas (Nosopsyllus fasciatus), and human fleas (Pulex irritans).
While the plague is the most severe infection transmitted by fleas, these pests also transmit Murine typhus, flea-borne spotted fever, and Rickettsial disease among other infections.
Pets bear the brunt of flea infestations and are at high risk of contracting flea-borne diseases including flea-related dermatitis, anemia, and tapeworms.
Fleas need a host in order to survive – but how long can they live without feeding? A flea may complete its entire life cycle in a few months to a year depending on conditions such as temperature, humidity, and the availability of a host.
Let’s take a closer look at the life cycle of fleas before answering the question.
Understanding the Flea Life Cycle
Stage 1: Eggs
Adult fleas lay their eggs on a host, usually a pet. The eggs are easily dislodged from the host when the pet shakes, scratches, or moves. The eggs fall to the ground, floor, pet bedding, sofa, or any of the places where the animal frequents.
The flea eggs measure about 0.5mm long, are pearl-white and have a smooth, oval shape. Flea eggs hatch into larvae in 2-12 days depending on conditions. The eggs make up the largest percentage of a flea infestation, accounting for roughly 50-54% of the flea population.
Stage 2: Larvae
Once the eggs hatch, this stage is known as larvae or larva in the singular. Larvae have a maggot-like appearance, are pale or translucent in color, and measure 2mm long when hatched. Once fully developed, the larvae will measure up to 5mm long and take on a darker color.
The larvae prefer dark conditions and hide away in dimly lit areas such as between floorboards, inside crevices, and in carpets. Flea larvae have strong, well-developed mouths and feed on their skin shedding, feces of adult fleas, other animal waste, dead skin cells, animal fur and hair, and other organic debris.
This stage lasts 2-14 days depending on the conditions. Larvae shed their skin (called molting) three times before transforming into pupae. Larvae make up roughly 35-37% of the flea population.
Stage 3: Pupae
In the pupal stage, the flea larvae spin a silky cocoon from gossamer, which is the same substance that spiders produce to weave their webs. The cocoon is sticky and attaches debris including dirt, dust, and flea feces to create a hard shell.
Flea pupae are the most difficult stage to exterminate on account of the protective shell. The pupae are difficult to vacuum up and exterminate with insecticide sprays. This stage lasts between 5-14 days, although the pupae may get stuck in this stage for up to a year in unfavorable conditions.
Pupae account for roughly 8-10% of the flea population.
Stage 4: Adults
Adult fleas require some nudging to come out of their cocoon. The adult flea will wait for external signals that a host is available, including the presence of exhaled carbon dioxide or vibrations caused by the host’s movement. The adult can remain in the cocoon for up to 5 months in unfavorable conditions.
Adult fleas measure 1.5-4mm and are brown-black or reddish-brown. The first order of business once the adult flea emerges is to find a blood meal. Although flightless, adult fleas have strong hind-legs which allow them to jump onto hosts.
A female adult can start laying eggs within 36-48 hours of her first blood meal. The typical female lays 20-30 eggs in a day and up to 800 in her lifetime depending on the species.
Adult fleas typically live between 60-100 days but can live for up to a year under ideal conditions. Adult fleas make up about 5% of the flea population.
How Fleas Feed
Fleas live on blood exclusively. These parasites prefer hairy animals including cats, dogs, rabbits, mice, rats, possums, and other wild or domesticated animals. In the absence of their preferred host (furry animals), fleas will happily feed on humans.
Flea mouthparts are especially suited for sucking blood. For this purpose, a couple of mouthparts come together. The laciniae, which are two saw-like parts, are tasked with cutting the skin. The epipharynx is a needle-like part that sits in the middle of the two laciniae on either side. All these organs together make up the stylet, which pierces the skin.
The flea cuts open or pierces the skin to get to the blood vessel and uses the epipharynx to suction blood to feed. At the same time, the flea injects an anticoagulant to ensure that the blood doesn’t clot while it feeds. This chemical can cause allergic reactions in some humans and pets.
Under ideal conditions, fleas feed daily. A typical flea will consume up to 15 times its body weight in blood. Adult fleas feed for up to an hour before becoming fully engorged. Fleas typically feed at least once every 12 hours.
How Long Do Fleas Live WITH a Host?
Generally speaking, an adult flea lives for about 2-3 months with regular access to a host. The parasite’s life span also depends on other external conditions. The optimal conditions for fleas are 85% relative humidity and 85 degrees F.
How Long Do Fleas Live WITHOUT a Host?
The average flea can only survive for four days to one week without a host. It is for this reason that an adult flea may remain in its cocoon until outside conditions indicate the presence of a host.
Fleas need to feed constantly to survive which is also why they prefer to live on their host. It is also worth noting that female fleas cannot lay eggs until they have had their first blood meal.
Hiding Places: Where Fleas Live
It helps if you know where fleas like to hide so you can maximize your chances of winning the battle against these invaders. Here are a few places where you should inspect in case you suspect a flea infestation in your home.
On pets. The most obvious place to start is with your pets. As previously mentioned, fleas like to live on furry animals, and their bodies are adapted to living in pet fur. Their narrow bodies, spiked legs, and strong mouthparts allow the pests to navigate fur, and to hold on tight even when the animal attempts to shake or scratch them off.
On humans. Although rare since fleas prefer to hide deep inside animal fur, fleas will occasionally infest humans if the preferred blood meal is scarce. Fleas typically bite humans on the feet, legs, and ankles although bite marks may appear anywhere on the body.
In carpet. Fleas in all stages often hide in carpet fibers, away from light and human activity.
On furniture. Flea eggs, larvae, and pupae may also be deposited on furniture including beds, pet beds, armchairs, sofas, and any other furniture that your pets come into contact with. The pests like to stay away from light and will hide inside crevices, cracks, and upholstery on furniture. This makes them even more difficult to spot and treat.
High places. As cat owners can confirm, cats like to roam strange and high places including on top of shelves, appliances, and other out-of-the-way places. Cats are more effective at spreading fleas around the home than dogs and require extra attention in the event of an infestation.
In the yard. Fleas aren’t just a nuisance indoors. These pests can also live outdoors given the right conditions and are usually to be found in outdoor areas where your pets eat or play.
Under Leaf Piles. It is not just your pets that may be spreading fleas around your property. Wild animals that scavenge in or around your yard can also deposit the tiny pests. The fleas may hide on grass or under leaf piles and wait for an opportunity to jump on a host.
Signs of a Flea Infestation
There are a couple of signs that you can look out for to determine whether you have fleas in your home.
Fleas are barely visible to the human eye but you may chance upon one or two around your home such as on your carpet, drapery, or furniture. Keep in mind that fleas don’t fly, nor do they have wings, otherwise you are dealing with a different insect.
Fleas on your pet’s fur often look like dots or like someone sprinkled black pepper all over your dog or cat. Take a fine-toothed comb and brush the animal’s fur. If your pet is infested by fleas, you should be able to catch and identify them on the comb. Inspect your pets if you notice them excessively scratching, biting, or licking their fur.
Read More: Flea and Tick Prevention for Dogs
Fleas also leave distinct bite marks when they bite humans. You should notice a red, itchy bump on the bite area. If bitten multiple times, you will notice red spots with red halos around them.
Other symptoms may include swelling around the bite, a rash, or hives. Keep in mind that some people are allergic to the coagulant that fleas inject into your body. Symptoms of an allergic reaction include wheezing or shortness of breath, intense itching, severe hives or rashes around the body, swelling of the face, lips, mouth, and hands.
If you notice black or brown flakes on your bedding or your pet’s bedding, you may be looking at flea feces. Take a piece of tissue and dip it lightly in water. Blot the flakey substance with the damp tissue and check for a reaction. If the tissue turns a reddish-brown color, chances are that you have found flea feces. Flea feces are digested or partially digested blood.
Quick Tips to Prevent Fleas at Home
Use flea treatments for pets – there are many flea treatments specifically designed for your pets. If you live in a high-risk area, consider monthly treatments. Pets are the primary hosts for fleas in and around the home so it makes sense to start your treatment here.
Vacuum clean regularly – vacuum your home thoroughly to pick up fleas in any of the life stages. Pay attention to flea hotspots such as pet furniture, upholstery, rugs, and carpets. Vacuum at least once a week and wash your pet bedding frequently to prevent fleas.
Insect Growth Regulators – insect growth regulators (IGR) are great for treating flea hotspots including baseboards, upholstery, carpets, and pet bedding. These insecticides are also available for outdoor use to control fleas that might be hiding outside. Insect growth regulators interfere with the insect’s natural development either by preventing the flea from maturing to the next stage in its life cycle or causing adult fleas to emerge from their cocoon before they are ready to reproduce.
Liquid Residual Insecticides – insect growth regulators take up to 6 weeks to work, and you might need something quicker in the interim. Liquid residual insecticides work on contact and are mainly targeted at adult fleas.
Many of these products have low toxicity to mammals and are largely safe to use around humans and pets in the correct dosage. These liquid insecticides retain their potency for up to three months after application. Consider using liquid residual insecticides along with insect growth regulators since fleas in the pupae stage are difficult to treat with insecticides on account of their protective encasements.
Diatomaceous Earth (DE) – diatomaceous earth is a non-toxic way to treat fleas in your home. The silica around the diatom cells dries out the insect’s exoskeletons, effectively killing the pests. Silica, which is a component of glass, cuts open the waxy exoskeleton of the insect. Sprinkle DE on dog beds, carpets, furniture, or any other places where you suspect that fleas might be hiding. Diatomaceous earth works for fleas in all life stages. Just be sure to vacuum up the powder after three days of application and apply the dust once a week for 30 days for the best result. Use food-grade diatomaceous earth which is safe to use around humans and pets.
Flea traps – flea traps don’t exactly prevent or eliminate fleas but are still a good early warning system. The sooner you find out you have fleas, the quicker you can tackle the problem. Flea traps use a combination of heat, light, and a sticky surface. Adult fleas are attracted to the light and heat suspended over a sticky mat. The pests jump on the mat and are trapped. Flea traps are great for homes with pets.