What Is a Flea? What Does It Look Like? - Cat Info Detective

What Is a Flea? What Does It Look Like?

Skye Blake-updated, white background

Greetings itchy kitties! Skye Blake here reporting on those nasty pests… fleas. What are they? How do you get rid of them?

Your favorite feline is scratching her neck and head, along with biting furiously at her tummy and back end.

What’s making her do this? Most likely its fleas.

paw prints coming in from a distance

Those nasty little bugs that bite and suck the blood of mammals… yuck!

They make us cool cats itch and scratch, and they bother people too! 

All sources are given at the bottom of each page so you can do more snooping. 

The information here is for general knowledge… always see your vet with questions about your cat’s individual needs. 

Who Is Skye Blake?

Skye Blake-updated, white background

Skye Blake, Cat Info Detective, is a curious cat researcher (not a veterinarian) who sniffs out expert, reliable sources about cats, studies their information, then passes it on to you! 

Sometimes there’s not enough evidence for easy answers, so Skye gives you all sides, explains the situation as thoroughly and clearly as possible, and links you to experts on each page. 

All sources are given at the bottom of each page so you can do more snooping. 

Fleas Are a Problem Because…

Closeup of a flea
Closeup of a flea among hairs
  • Their bites are very itchy and can cause severe reactions in cats and people (flea allergy dermatitis)
  • They can transmit tapeworms to cats
  • They can make animals very sick with anemia and other diseases, especially young, small or those with weak immune systems
drawing of a flea

Fleas differ from ticks because they scurry around quickly and don’t hang on long when they bite.

Ticks move slower and stay attached a long time (unless you remove them).

There are over 2,000 species of fleas worldwide! The two found on cats and dogs in North America are:

Orange Tabby Cat Scratching
  • Ctenocephalides felis (cat) – most common in North America
  • Ctenocephalides canis (dog) – relatively rare in North America

Both types can infest cats, dogs and humans, as well as more than 50 other animals, including raccoons, weasels, opossums and badgers.

What Scientists Say a Flea Is

Scientist pouring liquid into a test tube - vet

Here’s what some smart humans at Purdue University have to say…

“Adult fleas typically are about 1/8 inch long, oval, and reddish-brown. They are wingless, and their bodies are very thin, so thin that they can move freely through fur or feathers of their host.

drawing of a flea

They possess very large hind legs that are used for jumping and a very slender proboscis (beak) that extends forward when [it] takes a blood meal. At rest, the proboscis projects downward and backwards between the legs, but it cannot be seen without the aid of a microscope.

Dark tabby cat scratching his face while standing

Similarly, recognition of… larvae and pupae typically require the use of a microscope. To the unaided eye, the legless larvae resemble tiny whitish ‘worms.’

[The] pupae most likely would not be recognized at all because they are encased within a sticky cocoon covered by incorporated soil particles and small items of debris from the habitat in which the larvae develop.”

Stages of Flea Life

cat scratching

Below is a picture showing the four stages of their lifecycle.  

The only stage you’ll probably see is the adult, so here’s what you’ll be vacuuming up and getting out of your house…

Life cycle of the cat flea

Life cycle of the cat flea
Illustration by: Scott Charlesworth, Purdue University,
based in part on Elbel, R.E., 1991, IN: Immature Insects, Volume 2

What’s “Flea Dirt”?

Photo showing flea dirt on an animal
Flea dirt on fur

Check out this photo of specks on an animal’s fur. Looks like plain ol’ dirt, doesn’t it? 

Comb it onto a paper towel, wet it and see if it changes color.

If the dirt magically changes to red… presto! chango, it’s flea dirt!  

Regular dirt stays brown… Yuck!  But don’t panic. There are many ways to deal with them.

Now, How Do I Get Rid of Them?

Orange Tabby Cat Scratching Herselsf

Now that you know better what these annoying little critters are in all their stages of life, you’re better prepared to figure out how to combat them both in your home (where most of them are) and on your favorite feline buddy.

Discover more about dealing with fleas, ticks, and treatments at “Cat Health“.


Sources used on this website are either primary or secondary.

Primary sources are always preferable and have the most reliable information because they’re original and directly referenced.

Scientific abstracts and data are good examples of primary sources.

Secondary sources are weaker because they usually consist of opinions or articles that give no sources of their own.

However, sometimes they refer to primary sources.

When I use secondary sources, most are those with some authority, such as veterinarian or cat behaviorist books and articles.

List of Sources

“Fleas”, Purdue University, Medical Entomology, Insects and Ticks, by Catherine Hill and John MacDonald, 2008

Updated April 14, 2024

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