How Do Fleas and Ticks Survive the Winter?

5 min read


By Paula Fitzsimmons


Think fleas and ticks are just a warm weather hazard? Though not as prolific in winter, external parasites pose a risk to you and your pet’s health in all seasons. Find out why proper flea and tick prevention must be a year-round priority for the health and safety of your pet.


A Flea’s Life


Adult fleas emerge from cocoons called pupae when stimulated by vibration, pressure, or carbon dioxide emitted from breath, and when temperatures can sustain their survival, says Dr. Jason Drake, a board-certified veterinary parasitologist with Elanco Animal Health.


“Fleas thrive around 75 degrees F, and it’s around this temperature when they complete their entire life cycle within just a few weeks,” Drake says. “They can stay within the cocoon up to 30 weeks at 51.8 degrees F.” 


Fleas don’t travel from place to place in search of a host. They’re opportunists who find a host, then hold on as long as possible. To snag a host, fleas face a light source and hop onto a dog or cat (or human, for that matter) when when they sense a shadow. After biting the host, female fleas will continue to feed on blood (unless something disturbs them), mate, and start laying eggs within 24 to 36 hours, he says.


“One female can lay up to 50 eggs per day for more than three months,” Drake says. “These eggs are laid on the pet, then fall off into the environment, accumulating in the largest numbers wherever the infested pet spends the most time, such as bedding or on furniture.”


Flea larvae, which resemble maggots, hatch and feed on semi-digested blood present in adult flea feces, then form a cocoon and pupate in the environment. “Within the cocoon, the flea larva undergoes metamorphosis and eventually emerges from the cocoon as an adult flea.”


A Tick’s (Long) Life


The tick’s life cycle typically lasts two or three years. The most common ticks found on cats and dogs— referred to as three-host ticks—find a new host for each life stage, says Drake.


After the female mates and feeds on her host, she drops into the environment to lay a clutch of several thousand eggs, then dies. Once larval stage ticks—called six-legged larval stage ticks or seed ticks—hatch, they engage in questing behavior, where they climb onto nearby grass or vegetation, hold on their back legs, wait with their front legs in the air, and then grab onto an unsuspecting host. Once attached to a host, ticks then feed for several days, he says.


“Once fully engorged with blood, larval ticks drop off the host into the environment, eventually molting to their next life stage, the eight-legged nymph,” Drake describes. “Nymphs once again climb up onto grass or low vegetation, and wait for a second host to grab onto. Once on this second host, the nymph attaches and feeds for several days. Once fully fed, the nymph drops off the host into the environment and eventually molts to the eight-legged adult stage.”


When they become adults, ticks again climb onto grass or low vegetation and wait for a third host. “Adult female ticks attach and feed. Male ticks may also feed, but also search for female ticks to mate,” Drake says. “Some species of ticks mate while on the host, others can mate in the environment. After feeding and mating, female ticks drop off this third host and lay a clutch of eggs in the environment.”


Do I Need to Treat My Dog for Fleas in the Winter?


The short answer is yes. You definitely do need to protect your pet against fleas during the winter. 


The most common flea species, Ctenocephalides felis, typically overwinters on hosts or in protected areas, provided temperatures are mild. “No life stage of the flea (egg, larvae, pupae, or adult) can survive near-freezing temperatures for very long,” Drake says.


Adult fleas can be found on pets and wildlife throughout the winter, however. “Protected areas—such as areas under homes, barns, and wildlife dens—can stay warm and humid enough to support flea infestations through the winter,” he says. “As temperatures rise in the spring, immature stages of fleas are able to survive in the environment, allowing for adult flea populations to rapidly increase.”


Ticks survive winter differently than fleas. “Some ticks require a winter to develop from larva to nymph. Other species can easily overwinter in protected areas (snow on leaves helps insulate them) that are freezing and below, for prolonged periods,” says Dr. Thomas Craig, a professor and parasitologist with the Department of Veterinary Pathobiology at Texas A&M University in College Station.


The brown dog tick—a species that prefers dogs—has adapted for indoor life, says Craig, who is board-certified in veterinary microbiology. “Rhipicephalus sanguineus is able to withstand cool conditions in kennels and homes, but not really cold conditions unless it is attached to a host.”


Ticks have been known to survive temperatures well below freezing and become active again once temperatures rise above freezing, Drake says.


Protecting Your Pet Against Fleas and Ticks


Failing to protect your pet from fleas and ticks during winter can be costly to her health. Flea infestations lead to scratching, itching, skin irritations, and infections.


Ticks can transmit diseases. “Because ticks feed upon multiple hosts, they can act as vectors of diseases, becoming infected by one host, then transferring that infection to another host later in the life cycle,” Drake says. “There are many diseases that can be spread by ticks to pets and people, some of which are very serious, like Rocky Mountain spotted fever and Lyme disease.”


Keep your pet’s area clean by vacuuming carpets and washing bedding in hot water to kill fleas, and remove any ticks from her coat. Prevention is key, however, to reducing your pet’s risk of exposure to fleas and ticks.


A reliable preventive product is critical. “Because of the large numbers of eggs ticks and fleas can lay, it is important to use tick and flea products year-round in order to stop ticks and fleas before they establish infestations,” Drake says. “Fast-acting products that kill ticks and fleas quickly are important to help prevent eggs from being produced and to reduce the amount of time ticks and fleas can transmit diseases.”


Many of the older topical spot-on products are being replaced by products given orally, he adds. “Ask your veterinarian which product would be best for your pet.”


Learn More: