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Life Cycle of Cat Fleas

Cat fleas have a complex life cycle. The flea goes through a series of development before it matures into a feeding, egg laying, adult flea.

The Cat flea is: Ctenocephalides felis. It is called cat flea but can infect many other animals including dogs, cattle and rodents. It cannot survive biting only humans (a flea can only make viable eggs biting a human if it feeds for 12 consecutive hours!).

Fleas have developed clever adaptations to survive cat free periods or cold spells. By doing this the flea can retard its emergence from the pupa stage until a suitable cat comes around, or weather gets warmer.

Flea Eggs

After having a suitable blood meal, mature fleas start laying eggs in batches of about 20 eggs. A female can lay up to 50 eggs a day. Before feading, fleas are incapable of reproducing. In fact they must have a blood meal within the first day or so. Under ideal conditions fleas can live a year or more. Over the period of its life a flea may lay over 5000 eggs!

The flea eggs dry and harden. Because they are not sticky they fall off the cat and if conditions are good will hatch in as little as 2 days or as long as 2 weeks.

Cat Flea eggs will hatch quickly in warm damp environment. If the conditions are cool and dry they will delay hatching.

The egg hatches and a larva emerges

Cat Flea Larva

Cat Flea Larvae are about 3-5 mm long. They are translucent. To see what larvae look like here is my link to what fleas, eggs and larvae look like

Larvae are active and will eat enthusiastically. Their main food is flea dirt, already digested and excreted adult flea droppings. The larva also eat other organic matter.

Flea Larvae don't like bright light and will migrate away into the bedding and carpets.

If conditions are good and there is lots of food and nice warm humid conditions, the larva will spin a cocoon and become a pupae. This can happen in as few as 5 days or about 20 days from hatching.

Cat Flea Pupae

Once the larvae has spun a cocoon it gradually develops into a mature flea. The pupae stage is difficult to see because the cocoon is sticky and bits of organic matter and sand will stick to it and disguise it.

If conditions are good, then a hungry adult cat flea will emerge from the cocoon after one or two weeks.

The adult flea is now desperately hungry and must eat within a few days or it will die.

If the conditions of the pupae are not good, very cold or no cat around, then the flea will delay emerging for up to several months or over a year. This allows fleas to survive when there are no hosts nearby

There are several triggers that will cause the flea pupae to emerge from the cocoon, vibrations near, higher levels of carbon dioxide and rise of temperature to near body heat, have been identified.

This can be caused by a cat walking into her favourite sleeping place, but may also be people walking and creating vibrations near the cocoon.

Adult Flea

photo of flea

When it emerges the adult cat flea is desperately hungry and must eat within a few hours or it will die.

If the newly emerged adult cat flea has a blood meal, then it mates and starts laying eggs within a few days.

A flea cannot lay eggs until she has had a blood meal. Human blood is not satisfactory for this, or rather a flea has to feed for 12 hours in order to be able to use human blood.


Newly hatched fleas are smaller and darker than older fleas. Adult fleas spend most of their time living on the cat, feeding and laying eggs.

The cat flea is not a fussy eater and will nibble on dogs racoons, weasels, skunks, rabbits, squirrels, foxes, calves, and humans as well as many other animals.

Once the newly emerged flea has had its first blood meal, it can go long periods before eating again. Several months to a year is possible.

Because conditions are better, there are more fleas during the summer than during the winter. Higher summer temperatures and humidity are better for flea growth. Preferred conditions are 27C-32C with 75-92% relative humidity.

Fleas are very skillful at moving in fur. Because it is covered in backward facing hairs it can move very fast forwards. It is also covered in a tough exoskelleton that is extremely slippery. Another advantage a flea has is its flattened body which allows it to slip in between hairs.

The adult flea is a fabulous athlete and can jump several feet in the air, but most jumps are about 18 inches. They have large back legs which helps in jumping and in propelling themselves in fur.


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.