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What does a Cat Flea Look Like

appearance of a cat flea

Cat Fleas, Ctenocephalides felis, are wingless flattened insects. Adult cat fleas can range in colour from quite light reddish brown to quite dark almost black. It is likely fleas adapt to the colour of their hosts.

Cat fleas are great athletes with huge back legs well suited to jumping. Leaps of over a meter have been reported but most fleas leaps will not exceed the height of a cat, under a foot.

These athletic back legs are also used to quickly propel the flea in the fur of the cat or dog.

Because fleas are flattened and their body hard and slippery, they easily move between hairs, or clothing, helped by their backwards pointing bristles. Anyone chasing a flea in a cat knows how agile and quick they can be. This also allows the flea to move quickly in carpets or bedding.


Although cat fleas are quite small. 1-3 millimeters, they can easily be seen. The best place to look for them is at the base of the cat's tail, between the legs on the belly and in spots that are hard for the cat to reach.

The adult cat flea is only one of the forms a flea can take. If you have adult fleas you most certainly have flea eggs, flea larvae, flea dirt, and flea pupa. These other forms are difficult to see and usually hidden in the bedding or carpets.

The cat flea is not restricted to cats but is the most common flea that bites dogs in North America. Raccoons, skunks, coyotes, opossums can all be bitten by cat fleas.

The Dog Flea, Ctenocephalides canis, is less common but is almost indistinguishable by eye from the cat flea. It can be found on cats as well as on dogs and other animals. Since treatment is similar for both kinds of fleas exact identification is not relevant. Treatment of dogs or cats differ because cats are much more likely to get easily poisoned than dogs are. Never use dog flea medicine on cats.

Flea combs are not very useful in ridding cats and dogs from fleas because you simply can't catch enough to make a difference, but they can be useful when checking if the cat or dog has fleas.


What does a Cat Flea Egg Look Like?

After a blood meal female fleas will lay eggs. Cat flea eggs look like translucent oval dots. The flea eggs are about .5 mm long.

appearance of cat flea eggs

Knowing what a cat flea egg looks like does not mean you are likely to see them. Because they quickly dry after being laid on the cat, they become slippery and harder and fall out of the cat's fur. The best place to look for flea eggs is in the cat's bed and in places the cat likes to sleep. If your cat has a large infestation then looking with a magnifier at the base of the tail, or on the belly might be useful. If there are enough fleas on the cat to see eggs, you will see fleas or flea dirt much more easily.

If there is flea dirt on the cat or in the cat's bed then it's likely there are eggs mixed in. The flea dirt will be dark, the eggs will have a whitish appearance.

Cat flea eggs quickly hatch into a flea Larva after 2 days to 2 weeks, depending on conditions. A warm humid environment is the best for fleas. What do cat flea larva look like?


What do Cat Flea Larva Look Like?

Cat Flea Larva are translucent wormlike creatures about 3 mm long, with small bristles.

The larva will have dark stuff inside. Although photographs of flea larva makes then look like they are reddish when they are back lit, they usually look transparent with blackish stuff inside. The Larvae are active and don't like light. They will move away quite fast and burrow into the bedding.

The cat flea larva eat cat dirt (adult flea poo) and other organic matter. Since this is essentially cat blood it is reddish and if you can shine a bright light behind the larva its appearance will be reddish.

After about 2 weeks, the larva transforms itself again and spins a cocoon and pupates. What does a cat flea pupa look like you ask?

What does a cat flea pupa look like?

Flea pupa are more difficult to see or rather more difficult to recognize than other stages of the flea life cycle. The flea cocoon is sticky and dust and dirt will stick to it. It is about 3-4 mm across. The pupating flea looks just like a piece of dust. If you can see eggs or flea larvae then most likely you can also see flea pupae. You just don't know that's what you are seeing because its appearance is just like the debris around it.

University of Florida has photo of Cat flea Pupae in their article on flea life cycle.

Although you will not see pupae easily you will see flea dirt. What does flea dirt look like?

What does flea dirt look like?

flea dirt in brushed out cat fur

Flea dirt makes a rich food source for flea larva. It can be found on the animal or in the bedding. It looks like little black dots. Sometimes the flea dirt will be elongated and curved.

An easy way of figuring out if it is flea dirt is to place the animal on a white surface such as paper or a white cloth, and ruffle the fur. If there is dirt it will fall on the white surface. If you wet these specs and they turn reddish brown then it's flea dirt, it will go reddish brown because of the blood content. If you wash a dog or a cat that has a lot of fleas, the water will turn red-brown from the flea dirt.

Finding flea dirt is probably the easiest way of being sure your cat has fleas.

If your cat goes outside or is exposed to animals that do and you are not treating them, there are almost certainly fleas around.

Freezing does not kill fleas. I once put a flea I found on one of my cats, late at night, in the freezer. I wanted to photograph it and I did not want it to dry out. I absolutely expected the flea to freeze and die a relatively painless death. When I put it under the microscope it gradually started moving and eventually was able to jump. Sadly for the flea, it got squished.

This shows how important it is to continue treating cats and dogs even after a few frosts.




The photos come mostly from Wikipedia, the flea dirt is Dr.Zak's picture from Wikipedia.
emails: Christine

This article is provided for information only. It is not to be used instead of consulting a VET. If your kitty is sick get some help.