​​How Long Do Fleas Live?

Fleas are minuscule, parasitic insects which infest the fur of our beloved pets, as well as feral and wild creatures. They are able to leap vast distances compared to their size, as far as 150 times their own length! These incredible jumping abilities mean they make easy work of landing upon and feeding on you or your pet.

We all know fleas are pretty difficult to get rid of; but once you have a flea problem, you have probably wondered how long individual fleas will stay alive.

In this article, we give you all the details about how long fleas live.


How long do fleas live

Cat Flea - CC Image courtesy of Clay Nichols

What Is The Lifespan Of A Flea?

Fleas are troublesome creatures which can make us begin to itch at the very thought of them. They can cause havoc for our pets, driving them to scratch and chew themselves raw trying to get rid of them. Unfortunately, fleas are rather hardy. There is no single insecticide which will totally destroy a flea population in one fell swoop.

There are many different kinds of fleas, but they all have a similar lifespan and behaviors. All the many types of flea are collectively categorized under the scientific order “Siphonaptera”. The most common flea in the US is the cat flea, or Ctenocephalides felix. This flea infests cats, dogs, humans and other stray or wild animals and birds, and is the type we will be focussing on in this article.

fleas on cats stomach

Fleas on cats stomach

Fleas love to live in warm and moist environments. In fact, this is where they thrive and breed the fastest. As adults, they subsist upon blood meals from their hosts, which are most often mammalian species. It is the saliva of the flea which causes the irritation felt by the victim of their bites. It contains a compound which pre-softens the skin so they can more easily feed upon the blood beneath.

Understanding the life of a flea is imperative if you need to get rid of them. Unfortunately, because fleas are so resilient, they are much easier to prevent than to get rid of. Previously just a summer concern, now that most households have indoor heating, fleas are able to survive all year round.

Flea eggs can remain in a state of dormancy for very long periods of time before they hatch. This can be in your yard, carpet or even within your furniture. Once conditions are right, they will hatch and lay in wait for a suitable host.

flea eggs in carpet

Flea eggs between carpet fibers

If a flea is undisturbed, in perfect conditions and with access to regular blood feeds - they can live as long as three months.

How Long Can Fleas Live Without Feeding?

Once a young flea has first hatched, they must find a host quickly if they are to survive. Generally, if they do not get a blood meal within a week, they will die of starvation.

Adult fleas can fare a little better without food. If the environment is favorable, they can survive for up to 15 days at 75.2 F and 78% humidity. If the temperature and humidity levels are lower, around 72.5 F/60% humidity - they can live for up to 12.3 days.

The very best environments are those which combine cool temperatures with high humidity. In these circumstances, fleas have been seen to live without food for as long as 40 days! In a clinical experiment, fleas were kept in a controlled environment which featured cool air at 100% humidity. In these simulated and rarely found conditions, the fleas remained alive for 70 days without feeding.

Once a flea has found a suitable host, they will generally begin feeding as soon as they can, sometimes in as little as a minute before landing on the host. They will usually continue to feed in repeated sessions for around 24 hours. If a flea hasn’t eaten previously, it can almost double its’ body weight and triple the soluble proteins within it during this time. However, if a flea falls off its host and doesn’t feed for 12 hours, it will have lost all the weight and protein it had gained. This tells us that a flea generally needs to feed every 12 hours to stay healthy.

A Feeding Flea

A Feeding Flea

In common household conditions, fleas will usually die after 4 days without a feed from a host. The youngest fleas reach a stage of dependency once they have found a host to feed upon after a few days. This means that they will have adapted to regular feedings and will require constant access to a source of blood until they reach maturity.

A good example of this was seen in a scientific study. Fleas which had never before fed were enabled to consume blood from a host for a period of five days. They were then removed, kept without food and starved to death within 2-4 days.  However, when previously unfed fleas only were allowed to feed for 12 hours, they did not reach the state of dependency, and in some cases survived for up to 2 weeks without food after being removed.

Flea Overhead View

An Unfed Flea - CC Image courtesy of Lynette Elliott

Although fleas can survive without food, they cannot breed. They are an “anautogenous” creature - meaning that they must consume host blood to be able to mate and reproduce. Female fleas must consume blood to be able to lay their eggs.

Therefore, breeding female fleas will need to feed off their host continuously to ensure their metabolic rate is sufficient to produce eggs. Such breeding females will often die within 24 hours if they are removed from their host.

Life Cycle Of A Flea

If we consider the life cycle of a flea in relation to that of other insects, it is not particularly long. The life cycle has 4 stages: egg, larva, pupa and finally adult flea. The entire process can take as little as two weeks to as long as many months. This variation is due to the environmental conditions which the flea is living and breeding in.

Flea Life Cycle Larva Stages

The female fleas lay eggs while they are attached to their preferred host. While the female herself is attached, the eggs are not, so they drop to the floor as the host moves around. These eggs will stay wherever they have landed until they are ready to hatch. If conditions are good, the flea larvae will usually hatch within 2-12 days of being laid by the female.

These larvae look nothing like an adult flea. Incredibly small, they are highly unlikely to be visible to the human eye. They are whitish-cream in color and have no limbs.

Flea Larvae

Flea Larvae - CC Image courtesy of Peter J Bryant

What they do have, though, are very strong mouths. They survive by eating the feces of other fleas, organic waste such as hair and dead skin - as well as their own sheddings. They tend to hide in household carpets or deep within bedding and furniture. During summer time, the larval stage takes around 4-24 days. It can take as long as 200 days during the cooler months.

A fully grown larva spins itself a cocoon in order to enter the pupa stage of the flea life cycle. This stage takes around 5 - 14 days, but may take longer under unsuitable conditions. Once it is ready, the young adult flea will emerge and wait for an unsuspecting host to come past.

Flea Cocoon

Flea Encased In A Clear Cocoon (Pupae)

Contrary to popular belief, fleas actually spend the majority of their life cycle on nearby surfaces rather than on a host. 95% of the flea life cycle is spent in the pre-adult stages.


As we have seen, the length of time fleas will live varies considerably based upon the stage of their life cycle, the surrounding environment and their access to a blood meal.

Even though these irritating parasites can be very tough to eradicate, knowledge is certainly the best weapon. Now that you understand the lifespan and life cycle of these horrible pests - you can tackle any future infestations in the most effective way possible.

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