Do Fleas Bite Humans During the Winter?

Fleas are parasites. They survive year-round in climates where temperatures approach freezing. They live on hosts both for food and for warmth and protection. In the winter, they survive the cold by living on a host such as a dog, cat or other mammal. Fleas will readily jump from host to host and hitch a ride to a new home. They need a blood meal from a host to survive and breed, so they will bite any warm-blooded animal at any time of the year to complete their life cycle.

  1. Egg Stage

    • Fleas lay eggs that are about 1/20th of an inch long and pearly white. The eggs are deposited on the host and then fall from the host to the floor within a couple of hours. Flea eggs can lay dormant for more than a year and will not hatch until there is an acceptable host. The larvae will only hatch when there is carbon dioxide and warmth present which indicates to them that a suitable host has entered their environment. This egg dormancy period is why vacationers often close up a winter vacation ski resort home in March and find a flea infestation when they come back to reopen the winter home in November or December.

    Larvae Stage

    • Flea larvae look like maggots and cannot develop in areas where there is direct sunlight. Flea larvae will only develop in undisturbed, shady places such as along baseboards, in carpets and under household furniture. The speed at which the larvae develops into a pupae is primarily determined by environmental factors such as humidity and temperature.

    Pupae Stage

    • Flea pupae generally emerge in eight to 13 days. They are whitish and can be found in places such as carpets, pet beds, furniture, soil and on vegetation. The pupae form a cocoon and remain in it for up to 30 weeks before hatching. Hatching will be delayed if emerging adult fleas do not sense a suitable host. Adult fleas can emerge in as little as 13 days and up to 35 days if an acceptable host is present.

    Adult Feeding Habits

    • Adults begin biting and feeding as soon as they find a host. Fleas find humans suitable hosts. Within 20 to 24 hours of taking a blood meal the flea will begin to lay eggs. A female flea can lay between 40 and 50 eggs a day, so it is easy to see how you can get a winter infestation of fleas from a single flea that hitchhikes a ride into your house in the winter.