Cat Flea vs Dog Flea: What Is the Difference?

What are the differences between cat fleas (Ctenocephalides felis) vs. dog fleas (Ctenocephalides canis)? Do you treat them differently?

What is the difference between cat fleas and dog fleas?

To understand the differences between cat fleas versus dog fleas, we must look at each species individually. Are their looks, diet, lifespan, and effects similar? 

Cat flea eggs are the beginning stages of the metamorphosing insect into adult fleas, the most common among cats and dogs. Both species of fleas are different, but the cat flea is far more widespread. The only true way to tell the difference between the two is under a microscope. 

Cat Flea (Ctenocephalides felis)

The cat flea eggs hatch into flea larvae, where they feast on a blood meal given to them by their parents via their fecal matter. That’s right, feces. Most of the larvaes’ diet is adult flea feces

Can you see fleas with the naked eye?

Yes, you can see an adult flea, although it’s easier to see the eggs in pets with darker coats. The eggs are white and make up 50% of the flea infestation.

Flea larvae usually molt through four stages before finally spinning their cocoon to enter the pupae stage. These stages and the egg stages are the easiest to spot. You can kill off the adults and then remove eggs since the eggs don’t stick to your pet’s skin.

What are the effects of flea infestations? 

A cat flea population will attack dogs and cats, hiding in the animal’s fur.

The skin in the area where the fleas are concentrated can become raw and red, sometimes accompanied by a rash from the fleas sucking blood. In addition, it may lead to excessive itching trying to get the fleas off of them and stop biting. Both dogs and cats can have flea allergy dermatitis, an allergic reaction to the flea saliva, and the flea problem really harms your pets.

The fleas shouldn’t be deadly for the average pet without serious health issues. However, all the scratching and biting can easily lead to secondary infections, meaning a death sentence for pets with autoimmune problems. So it’s still essential to seek treatment right away and not allow the fleas to feed on your pets. 

How to get rid of fleas on your pet?

It’s essential to stop any cat fleas or dog fleas found as soon as discovered.

Most over-the-counter medicine kills fleas, but be advised: if your cat generally has skin or stomach sensitivities, they could be allergic to various treatments against fleas, like the flea collar. Also, if left untreated, a flea infestation can cause illness in your pet. 

get rid of fleas on your petCat flea infestations can be treated with a simple dose of liquid treatment applied to the back of their necks. You can get over the counter, but it’s always wise to have a veterinarian take a look and help answer any related questions you may have about fleas. 

Dog treatments are the same, although you need to purchase a brand specific to dogs and not catered towards cats. This will help kill fleas, along with flea collars if required. 

Are there other parasites that look like fleas?

Bed bugs and human lice are two easy examples of other insects that look like fleas. There are plenty of other things it could be on you, your pet, or in your home. Multiple beetle varieties look pretty similar to fleas, especially in their juvenile state. 

Dog fleas vs. Human fleas

To start, human fleas are not often found in industrialized countries such as the USA, so if you are exposed to a flea in your home, chances are more likely that you have seen a pet flea. But be advised: Both types of fleas bite humans and attack cats and dogs alike. Also, if it is a human flea, be extra careful; they are known to carry the bubonic plague! So either way, do your best to get rid of fleas

For this topic, dog fleas and cat fleas are comparable to human fleas, so we will refer to them as “pet” fleas. However, despite their name, cat fleas are not hosting specific and will infect a wide variety of many other animals such as dogs, raccoons, opossums, foxes, and even rabbits in the back of your yard. 

Pet fleas have a more rounded abdomen, while human fleas are larger and have a straighter back, unlike the hunched back of the pet fleas. Human fleas can carry diseases that affect humans, so although they are not often found in the US, EU, and some western countries, they are still very dangerous and can be spotted almost anywhere. 

Brown fleas vs. Black fleas

While some species may differ slightly in looks, the main difference you will see in color on fleas is actually fleas that have fed and those that are feeding or have yet to feed. So that blackish-brown color is actually blood you can see inside them, as they are relatively transparent. 

Frequently asked questions:

Will the dog flea treatment kill cat fleas and vice versa? 

Yes, and no. The treatments for cat fleas and dog fleas are formulated specifically to match the size of an animal as best as possible. Therefore, if you use cat flea treatment on a dog, the dose would likely be too low and remain ineffective. 

Do cats carry more fleas than dogs?

Actually, it is more likely that dogs will carry adult fleas than a pet cat, especially during flea season. This is because fleas like to live in moist or damp areas, usually tall grass, where many animals such as ticks and other insects hide out. Therefore, a dog flea and a cat flea will be found in the same areas, and cats are less likely to walk through very tall grass and weeds. 

Are there any natural ways to deter fleas?

There are plenty of products on the market to kill fleas, including essential oils in their ingredient base to spray on carpeting and around your yard. 


The best way to remain flea-free is through proper maintenance treatments for your pets. It’s far easier to prevent fleas than remove them.

Human fleas are extremely dangerous, although rare. No matter what bug you have seen on you, your pet, or your home, it is a sign that something is wrong. There needs to be treated, whether fixing a hole in the wall, cleaning up the kitchen, or cleaning out an old, musty room.

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