Cat Fleas

Cat Flea Facts

• Scientific name: Ctenocephalides felis
• Size: adults are about 1 to 3 mm long, with females a little larger than males
• Color: shiny reddish brown to nearly black

Cat Flea Behavior

A female cat flea has to feed on blood before she can lay eggs. Once she starts, she lays steadily, often dozens a day, right on the animal. The eggs are smooth and not sticky, so they drop out of the fur whenever the pet walks, scratches or curls up to sleep. That is why the heaviest flea activity builds up around a pet’s favorite resting spots.

The larvae that hatch are tiny, white and wormlike. They eat organic debris, and their most important food is flea dirt, the dried droppings adult fleas leave in the fur that shake loose along with the eggs.

Identifying the Cat Flea

The cat flea’s scientific name is Ctenocephalides felis. (Siphonaptera is the name of the entire flea order.) Adults are tiny, wingless and reddish-brown to dark brown. The body is flattened from side to side, and their long back legs let them jump many times their own length. Under magnification you can see rows of dark spines, called combs, along the mouth area and behind the head.

Telling it apart:

• Dog flea: despite the names, the cat flea is also the flea usually found on dogs in the United States, and the true dog flea is uncommon. The two look nearly identical; the cat flea’s head is longer and more sloped, which takes a microscope to see.
• Bed bugs: flattened from top to bottom instead, rounder, and they crawl rather than jump.

Where it lives: once adults find a host and start feeding, they tend to stay on it. Eggs fall off into bedding, carpet and soil. Larvae avoid light and need humidity, so they work their way deep into carpet, under furniture and into shaded soil outdoors.

What it eats: adults feed only on blood. Besides cats and dogs, they feed on opossums, raccoons and other mammals, and they will bite people.

In Florida: the cat flea is the flea most often found on pets and in homes, and the warm, humid climate lets it breed year-round. In good conditions it can go from egg to adult in as little as two to three weeks. See also fleas.