Dog Fleas


Adult dog fleas are about 1/8-inch long, wingless, have six legs and are almost flat from side to side, a characteristic that allows them to easily move between the hair shafts of a host’s fur. Dog flea larvae are also small, but are cream-colored and have no eyes or legs. As they mature, they become dark brown. Identifying dog fleas requires a flea specialist who uses a microscope to correctly identify various species of fleas.


Dog flea adults spend their life on their host mammal unless the animal or something else dislodges them. Some of their common hosts are coyotes, foxes, wolves, dogs, woodchucks, rabbits, cats and rats. Animals that live outdoors in rural areas are more likely to be infested by dog fleas than animals that live inside as pets or in urban areas. In fact, pets that live primarily indoors are much more likely to be infested with cat fleas than with dog fleas. Within the United States, field researchers have concluded that about 90 percent of the fleas found on pets, whether dogs or cats, are cat fleas.

While not as plentiful as cat fleas, dog fleas do present an annoyance and potential health issue since they are known to be an intermediate host of dog tapeworm and rodent tapeworm. The flea’s larval stage ingests tapeworm eggs, which in time hatch and develop inside the flea. An infection of a person or pet occurs by accidental ingestion of a tapeworm-infested flea. Ingesting fleas accidentally happens when pets groom themselves or when children play with flea-infested pets.


Dog fleas are not picky about what host provides their blood meals since almost any warm-blooded animal will do. Larvae to not feed on blood; rather, they eat adult flea feces, commonly called flea dirt. Pupal fleas do not feed.


Dog fleas prefer to develop in protected areas that are frequented by their hosts and where the relative humidity is at least 75 percent and the temperature is 70-90° Fahrenheit. As one might predict, dog fleas do not live in habitats that are open to sunlight and are dry.


Dog fleas go through complete metamorphosis, meaning they develop in four distinct stages – egg, larva, pupa and adult. In general, it takes about 3-4 weeks to complete their life cycle, depending upon the warmth and humidity of their environment. Female fleas must consume a blood meal before eggs can develop and lay on a host. Soon after eggs are laid, they fall off the host and develop into the larval (maggot) stage. After completing three larval molts, flea larvae spin a silk pupal case that will surround the last stage larvae and the developing pupal stage. The pupal case protects the pupae and houses a stage of the adult that is called the pre-emerged adult.

Under ideal conditions, it takes only about 3-4 days for flea eggs to hatch, but more often they remain in the egg stage for up to a week. The dog flea’s larval stage lasts about 10-14 days and the pupal stage for 1-2 weeks. But, a most interesting phenomenon concerning the flea’s pupal stage is the fact that the pupal case may house a pre-emerged adult that will stay inside the protective pupal case as long as it takes for a suitable host to come near. If a host passes by, the pre-emerged adult will exit the pupal case upon sensing the presence of body heat, carbon dioxide and movement of a host and become a fully functional adult ready to feed on the host. Adult fleas can remain inactive inside the cocoon as pre-emerged adults for months before exiting the pupal case. After emerging the pupal case, adult fleas usually live about 3-4 weeks, but less time than that if they do not find a host and take a blood meal.


Seeing dog flea adults on pets is the most obvious sign of their activity. Other signs may include the presence of flea dirt and pet irritation from allergic reactions that develop from flea bites. These allergic reactions show up on pets as patches of purple bumps and swelling of the skin. Also, flea bites around the ankles of occupants of buildings and houses infested with fleas indicate fleas.


Preventing flea problems begins by caring for pets and the environment where fleas exist. Some prevention and reduction tips for use against fleas include:

  • Removing fleas and flea dirt from infested pets by regularly inspecting pets, removing fleas with a flea comb and bathing pets to remove eggs, flea dirt and adult fleas.
  • Washing and drying pet bedding or things they rest upon using the washer’ and dryer’s hottest settings.
  • Removing flea larvae, pupae and flea dirt by deep cleaning and vacuuming areas in which they are located. Also, steam cleaning of carpets is valuable.
  • Preventing urban and suburban animals from wandering onto your property. Also, make sure that shady spots are minimized as much as possible on the property since yards that are open to sunshine and have grass that is mowed short assist in the prevention of fleas outdoors.
  • Not allowing your property to become harborage for nesting and burrowing rodents or other animals.


Flea control is an integrated process that includes the following methods and materials, plus the items listed above:

  • Contact your pest management professional and request an inspection and flea management plan. Much of the time, this is the best way to obtain safe and effective control of a flea problem.
  • Use treatments and products for flea control on your pets (spot-on treatments) that are recommended by your veterinarian.
  • Use pest control materials in the house and yard at the same time you take your pet(s) to the veterinarian for treatment. Often, treating only a pet does not do much to reduce the numbers of flea larvae or adults that are present elsewhere.
  • Use insect growth regulators as part of the flea control effort.