Do Fleas Die in the Winter? The Disturbing Truth About Fleas in Winter

What’s your favorite season? For a lot of us, the answer is Summer. Long, warm days. Time off school. Everything green and growing.

But Summer has its downsides, and bugs are one of them. If you live in a temperate climate, and you’re not a fan of bugs, Winter can be your best friend.

Colder temperatures kill off many insects, and send most of the rest of them into hibernation, granting a temporary reprieve from bites.

Fleas happily live outdoors. Often, they are brought into human homes from pets that caught them outside. But can they survive the Winter?

Can Fleas Live in the Cold?

First, the good news. Cold temperatures kill fleas. Adult fleas can’t survive temperatures of 30°F for more than five days. Even at a slightly warmer 37°F, they won’t last more than ten days.

And the eggs are actually more susceptible to the cold, with even a relatively mild 46°F killing them within ten days.

Most insects, including fleas, lack the mechanisms we mammals have to regulate our body temperature and keep ourselves warm.

So if you feel a need to put on a jacket and stand outside in your yard laughing maniacally as the snow falls and kills off your insect enemy, go ahead.

Anybody who has had a flea problem in the past will understand.

But you didn’t think it would be that simple, did you? Now for the bad news. If fleas didn’t know how to survive the Winter, they would have died out long ago.

Do Fleas Die in the Winter?

Fleas have a couple of different strategies that they can use to get them through the colder months.

Freezing temperatures can take ten days to kill fleas. If, at any point in those ten days, the temperature climbs a little higher, the fleas will be able to endure.

Depending on where you live, this may or may not be an issue.

Fleas aren’t going to survive outside through an Alaskan Winter, but in South Florida, fleas can live outside all year long quite happily, able to withstand any cold snap that comes their way.

Plus, fleas are mobile insects, and they won’t just sit around waiting to freeze. If a flea is hiding outdoors in the cold and you or your pet walk by, rest assured that that flea will jump on and come along for the ride.

And if you or your pets bring that flea into your home, you just provided it with the perfect way to survive the Winter.

In fact, thanks to heated human homes, fleas can not only survive the Winter but thrive all the way through it, continuing to lay eggs and breed no matter what the temperature is outside.

How Fleas Survive Winters

Fleas don’t necessarily have to make their way into your living space to survive the Winter, either.

By entering frost protected places such as the crawlspaces of houses, they can avoid the worst of the cold and hang on until spring. Cooler temperatures will inhibit the flea’s breeding cycle, so they may not be laying eggs at this time.

Fleas aren’t capable of true hibernation. But if they haven’t yet emerged from the cocoon in which they pupate between the larval and adult stage, they can enter a kind of dormant state which can last up to five months.

During this time, the flea won’t need to eat. This makes it quite easy for them to survive until spring, so long as it doesn’t get too cold.

Don’t forget that even emerged adult fleas that have not yet taken their first blood meal can wait 100 days to do so. In many parts of the world, this is more than enough to get them through the coldest temperatures of the year.

Scared yet? You should be. Fleas have survived millions of winters before humans ever came on the scene.

Spring Always Follows Winter

Prolonged cold may kill fleas but Winter doesn’t last forever.

Often, flea populations explode in the spring as soon as the weather gets warm enough for them to become active and reproduce.

And because of the fleas’ staggering reproductive rate, no matter how many fleas die in the Winter, as long as a few make it to spring, they will quickly replace their fallen comrades.

We mammals shouldn’t be too smug, either. Fleas may not have our ability to stay warm in cold temperatures, but they have learned to use our method of heat regulation to their advantage.

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Adult fleas live out their lives on mammals, trying to avoid ever leaving like the world’s worst cruise ship passengers. If a flea can burrow into the fur of an animal such as a raccoon, coyote, deer or anything else, it can easily survive the Winter thanks to the animal’s body heat.

It may even stay warm enough to continue laying eggs, albeit at a slower rate than it would in the Summer. Most of these eggs will fall off the animal and die, but if even a few get stuck in the animal’s fur, they can hatch and join in the breeding cycle right through the Winter.

The Final Word on Fleas in Winter

Winter is coming. But it may not be the threat to the flea population you hoped it would be. Winter certainly kills a lot of fleas, and it slows down the reproductive rate, providing us blood-filled mammals with a reprieve from their itchy bites.

But you can’t rely on cold temperatures to kill all of the fleas. They’ll be back again in the spring. You can count on it. And of course, if you’re dealing with fleas in the house, the Winter won’t affect them at all. A heated home provides a perfect environment for fleas to live and breed in all year-round.

Still, you can use the cold weather to your advantage. Winter is the best time to try and get rid of fleas since you can be relatively confident that you and your pets won’t simply bring more back in from outside.

Then again, if you have fleas in your house, the best time to treat them is right now. Find out how to get rid of fleas for good. Waiting until Christmas isn’t advised.

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