20 Facts About Fleas and Dogs You Need to Know

Learning more about fleas and dogs will help you become better acquainted with these blood-sucking enemies and help you figure out what steps to take to eradicate them.

20 Facts About Fleas and Dogs You Need to Know

Learning more about fleas and dogs will help you become better acquainted with these blood-sucking enemies and help you figure out what steps to take to eradicate them.

Fleas in dogs are more than just a nuisance.

paisan191 via Getty Images; Image created via Canva

Some Basic Flea Facts for Starters

Here are some basic flea facts to begin learning how to deal with these nasty critters. Don't get discouraged by the unusual terms; I've provided simple explanations that will make the information easy to digest and comprehend.

1. Fleas Are Ectoparasites

Ectoparasites are simply parasites that live outside of the body of their hosts. Examples of ectoparasites that may be found on dogs are fleas, ticks, mites and lice.

The word "ecto" derives from the Greek word "ektos" which means outside. The word "parasite" instead derives from the Greek word "parasitos," which means "a person who eats at the table of another."

In biology, the term is used to depict opportunistic organisms which live at the host's expense (in this case, the host is the dog).

The opposite of ectoparasites are endoparasites, which are parasites that live inside the host's body.

Examples of endoparasites in dogs include a variety of intestinal worms such as tapeworms, roundworms and whipworms. The pesky heartworm, which establishes in the dog's heart, lungs, and associated blood vessels, is also an endoparasite.

Fleas are the most frequent external parasites that are encountered on companion animals worldwide.

2. Fleas Are Hematophagous

Hematophagous is simply a term used to depict animals, especially insects, that feast on blood. In other words, fleas are little vampires.

To get an idea of how much blood fleas suck, consider this: female fleas of Ctenocephalides felis (the most common type of flea found on dogs) have been known to consume up to 13.6 ml of blood per day.

That's the equivalent of ten to 15 times their body weight!

3. Fleas Are Holometabolous

In other words, they go through a complete metamorphosis which includes four life stages. The life stages include the following: egg, larva, pupa, and adult.

Once hatched from eggs, fleas enter the larva stage. After completing two molts, the larvae spin a cocoon and enter the pupal stage. Afterward, the fleas emerge from their cocoons and mature into adults.

The entire life cycle may range between 21 days and three months. Ideal warm temperatures (80 to 85 degrees) seem to expedite their development.

Other examples of holometabolous insects include butterflies, moths, beetles and bees.

4. Fleas Are Apterous

The term apterous simply means lacking wings. Indeed, fleas can't fly.

Instead, they're capable of effectively hopping from place to place on your dog with the ability of an Olympic-level jumper.

Their jumps happen courtesy of their highly developed hind legs, which allow them to leap as far as eight to ten inches in height and 12 inches in width. That's 150 times their own body length!

5. Fleas Are Ancient

Did you know? Fleas have been known to infest humans and animals as far back as the Palaeocene (Alcaíno et al. 2002).

Getting rid of fleas is not an easy task, but the more you know about fleas, the better.


More Flea Facts You May Not Want to Know (But Need to Know)

These flea facts can be a tad bit repulsive, but it's important for you to be aware of them because the more you know about your enemies, the better equipped you'll be to combat them.

6. Flea Eggs Live in Your Home

Fleas have to find their own creative ways to reproduce and hide in sneaky ways. Otherwise, they wouldn't have survived for long!

Female fleas will lay their eggs on your dog's fur, but they will also spread in a variety of inconspicuous places around your home as they fall off your dog's coat.

Being roundish or oval in shape, flea eggs easily roll into cracks and crevices that are found around your home.

Favorite hiding spots are your dog's bedding, cracks in the floor, the base of carpets and under sofa cushions. Flea eggs thrive in these areas as they do best in humid and repaired places.

The number of eggs produced by female fleas is astounding. In general, an average of 40 to 50 eggs are produced daily!

7. The Fleas on Your Dog Are Only the Tip of the Iceberg

To get a better idea of how many fleas are living in your home, consider that your dog will likely carry only one to five percent of the flea population, while the remaining 95 percent are hiding around your home, in cracks in your floors, at the base of your carpet and under cushions.

Out of all the fleas in your home, note that over 50 percent consist of flea eggs, 25 to 35 percent are larvae, and 10 to 15 percent are in the pupal stage.

Fleas may also live outdoors, particularly in shaded areas that are humid, such as crawl spaces, decks and porches.

The fleas that you see on your dog are only the tip of the iceberg.


Flea Facts About How They Impact Your Dog

Fleas can surely make dogs quite miserable! Let's now take a closer look into how they interfere with a dog's health and well-being and, ultimately, wreak havoc on their bodies.

8. Fleas Can Cause Anemia

Severe infestations with fleas can cause anemia, especially in young puppies. They may develop pale gums as a result.

Chronic iron deficiency (anemia) may also be seen in adult dogs living in areas that are commonly infested with fleas and hookworms, explains Dr. John W. Harvey, a board-certified veterinarian specializing in pathology.

9. Fleas Can Cause Allergies in Dogs

It's called "Flea Allergy Dermatitis" often abbreviated as "FAD." This allergy is really to the flea's saliva rather than the fleas themselves.

This skin condition is one the most commonly seen in small animal practice in most countries in the world, explains Dr. Peter J. Ihrke, a board-certified veterinarian specializing in veterinary dermatology.

Affected dogs are incredibly itchy, especially around the tail base, leg thighs and back. Just one flea is enough to make a dog go literally nuts.

Dogs with FAD will present with hair loss, crusts and itching that causes self-trauma. Secondary bacterial and fungal skin infections may arise as a result of constant scratching.

10. Fleas Can Cause Worms in Dogs

In this case, we're talking about the canine tapeworm (Dipylidium caninum), which can use fleas as intermediate hosts.

Dogs get tapeworms by grooming themselves and accidentally ingesting a flea that is infested with tapeworm larvae. Once ingested, the tapeworm will establish itself in the intestinal tract by attaching its head to the dog's intestinal wall.

While we really can't see tapeworms (as they live inside the dog), we may see proof of their existence due to their eggs being released in small rice-like segments (proglottis), which contain reproductive organs and eggs.

These segments are expelled through the dog's feces, and you may see them on your dog's poop or bum (or surrounding hairs) or in places where your dog often sits and lies down.

One of the main signs a dog has worms, in this case tapeworms, is therefore, the presence of what looks like several grains of rice on a dog's stool.

Yes, flea bites are a real thing!


Flea Facts About How They May Impact You

The term "zoonoses" is meant to depict diseases capable of being transmitted to humans. Sadly, there are several conditions that may be seen in humans as a result of being exposed to dogs and their fleas.

11. Yes, Fleas Can Bite Humans Too!

While we're not their preferred item on the menu, fleas won't hesitate to bite us and then decide whether they should stay or move on for something better.

Flea bites on people are usually concentrated on the ankles and lower parts of the leg.

In most cases, fleas are just transient guests as they'll look for better meals, especially when they land on Rover's coat, providing them with the perfect means to hide.

Did you know? In the past, on top of providing companionship and warmth, lap dogs were also used to attract fleas away from their owners.

12. Fleas Can Cause the Plague

In the past, fleas have been known to cause the plague, also known as the Black Death. The plague has been known to have caused the deaths of a third of the world’s population during the Middle Ages (Gubler 2009).

However, the common flea found on cats and dogs doesn't appear to be associated with the type of flea responsible for causing the bubonic plague.

13. You Can Get Tapeworms From Fleas as Well

All that is needed is for you to ingest an infected flea accidentally. Well, this is not very common, but it's not impossible. Snoring with your mouth open? Kissing your dog?

Children may be more at risk as they are often closer to the floor, crawling on four legs and putting their dirty hands or just about anything in their mouth. They may ingest an entire flea or bits of fleas that may get stuck under their fingernails.

Flea dirt is one way of detecting fleas in dogs


Facts to Promote Flea Eradication

As mentioned, knowledge is power, and the better you know fleas, the more you'll be able to succeed in removing them from the environment.

I should throw a disclaimer in here; the process is not easy, especially when you own multiple pets (such as cats who live both indoors and outdoors).

14. Fleas Produce Flea Dirt

The first step in eradicating fleas is ascertaining whether your dog actually has them. Flea dirt is one of the best ways to identify the presence of fleas on a dog.

While the term "flea dirt" sounds quite innocent, in reality, its definition is rather yucky.

Flea dirt is simply waste that's originating from adult fleas. To put it bluntly, flea dirt is a flea's poop that consists of partially digested blood.

How can you tell whether those little black spots on your dog are dirt or debris or actual flea dirt? It's fairly easy: place some of those black specks on a wet paper towel. If they leech a reddish-brown color, it's flea dirt.

Now that you know your dog has fleas, it's time to figure out how to get rid of them. Your veterinarian will help you out with this, but here's a little intro so that you know what to expect.

15. Fleas Can Be Caught With Special Tools

Flea combs or nit combs can help you find live fleas or traces of flea dirt. Simply brush your dog and see what you caught along with your dog's hairs.

If there are fleas, drown them by placing them in a bucket filled with soap and hot water.

However, remember that the fleas on your dog are only the tip of the iceberg. To effectively eradicate fleas, you'll have to kill all life stages.

16. Regular Vacuuming Can Help

If your home is mostly composed of carpet, regular vacuuming can help suck up a large percentage of flea cocoons.

17. Fleas are Attracted to Light

While flea larvae dislike light, adult fleas are attracted to it because when the light turns into a shadow, that triggers them to jump as the shadow is perceived as a body walking by.

Due to this preference, commercial lighted flea traps were invented. A homemade version can be made by placing a dish full of soapy water under a night light.

However, fleas that are already on dogs are not attracted to light. Indeed, if a dog rolls over his back, exposing the belly to the sun, the fleas will scurry away to areas with more fur.

Flea traps are not the ultimate solution for eradicating fleas but can be used in conjunction with other strategies.

18. You'll Need to Treat Your Dog...

Treating your dog is the rather easy part. There are several products designed to kill fleas, and they can be very effective.

If you own other pets, it's fundamental that they are treated too. Caution is needed in families that own both dogs and cats, as some products designed for dogs are toxic to cats.

There are several products designed to kill fleas on dogs nowadays. You'll find flea collars, spot-on applications and even oral pills.

A word of caution is needed in using non-prescription flea products commonly sold in stores. These are notorious for causing allergic reactions with intense scratching and even rashes.

If your dog develops a reaction to a flea product, the EPA recommends reading the precautionary statement on the product's label. If they do, contact the vet immediately and bathe the dog using mild soap and rinsing with copious amounts of water.

19. And the Surrounding Environment Too!

After taking care of your dog, the next step is the most challenging: killing all the eggs, pupae and larvae from the environment.

The next step is to wash your dog's bedding at 140°F, and vacuum carpets, cushions and furniture daily, while being careful to dump all contents outside of the home in a closed bag.

The environment should be sprayed using insect growth regulators specifically designed to kill all life stages of fleas. Follow the instructions carefully and remove your dog from the environment for as long as the labels suggest.

Fumigation remains the most effective method but should be carried out by professional flea exterminators.

Treating the environment is the most time-consuming process considering that you'll have to kill all components of life stages, and therefore, it can take, at a minimum, two to three months to see the effects.

Afterward, flea prevention strategies will need to be implemented year-round, ideally without interruption. Fleas season appears to be a year-round ordeal nowadays! Follow your vet's recommendations and instructions.

20. To Kill Fleas, You'll Need to Follow the Guidelines

Some of the most common causes of flea treatments not working is not following flea eradication programs correctly. Factors that may cause flea infestations to recur include the following:

  • Not treating all pets in the household
  • Missing flea treatment doses
  • Interrupted treatment
  • Lack of year-round prevention
  • Incorrect administration
  • Bathing dogs who are spot-on treatments earlier than 48 hours
  • Stray cats or flea-prone wildlife visiting the yard
  • Use of natural or ineffective products
Fleas are fairly easy to remove from your dog as long as you keep up with the treatment plan. The environment is more difficult to treat.


  • Iannino, Filomena & Sulli, Nadia & Maitino, Antonio & Pascucci, Ilaria & Pampiglione, Guglielmo & Salucci, Stefania. (2017).
  • Fleas of dog and cat: Species, biology and flea-borne diseases. Veterinaria italiana. 53. 277-288. 10.12834/VetIt.109.303.3.
  • Ultimate Guide to Flea Control by Luke Styles
  • Top 100 Questions and Answers about Fleas and Pets By Hany Elsheikha, Ian Wright and Michael Dryden
  • Flea Allergy Dermatitis World Small Animal Veterinary Association World Congress Proceedings, 2006Peter J. Ihrke, VMD, DACVD

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2023 Adrienne Farricelli

(Excluding for the Headline, this article ("story") has not been edited by MiBiz News and is published from a web feed or sourced from the Internet.)