Ticks don’t jump, fly, or drop from trees. They crawl onto you from ground-level vegetation, usually latching onto your shoes, socks, or lower legs as you brush past them. From there, they climb upward across your body, often ending up near your head or ears before biting. Understanding exactly where and how this happens can help you avoid them.
How Ticks Find You
Ticks use a hunting strategy called “questing.” They climb to the tips of tall grass, low shrubs, or leaf litter and extend their front legs outward, waiting for something warm-blooded to walk by. When you brush against that vegetation, the tick grabs on with tiny claws on its forelegs, snagging fabric or skin on contact.
The carbon dioxide you exhale is the primary trigger. Even at low concentrations, CO2 activates ticks and prompts them to start waving their forelegs in preparation. It doesn’t pull them toward you like a magnet. Instead, it functions more like an alarm clock, waking them up and priming them to grab on when something passes within reach. Body heat and moisture likely play supporting roles, but CO2 is the critical first signal.
Once a tick is on you, it crawls until it finds a spot it likes, often somewhere warm and hidden: behind the ears, along the hairline, in the armpits, or behind the knees. It then burrows in with barbed mouthparts that work like tiny ratchets, locking it in place. Its saliva acts as a cement, gluing it to your skin. This is why attached ticks can be surprisingly difficult to remove.
Where Ticks Live
Ticks need humidity to survive. Research from the U.S. Geological Survey found that at 75% humidity, less than a third of ticks survived temperatures in the 90s for more than four days. At 95% humidity, roughly four-fifths survived the same heat. Ticks that can’t find moisture die within days. This is why they concentrate in shaded, damp environments rather than open, sunny lawns.
The highest-risk habitats include deciduous forests, overgrown trails, and areas with thick leaf litter. In residential settings, a Connecticut study found that the border zone where a mowed yard meets forest is the prime hot spot for ticks. Stone walls were another concentration point, because the mice and chipmunks that carry ticks nest inside them. Interestingly, woodpiles, bird feeders, and unmown grass were less likely to harbor ticks than expected, probably because woodpiles lack the permanence that makes stone walls attractive to rodents year after year.
Common Ways People Pick Up Ticks
Most tick encounters happen during ordinary outdoor activities, not deep wilderness expeditions. Hiking through wooded trails is the classic scenario, but gardening near the edge of your yard, walking your dog through tall grass, or even chasing a ball into a brushy area behind your house can be enough. Cornell’s integrated pest management program notes that it’s almost impossible to pinpoint exactly where you picked up a tick, because it could have latched on during any brief contact with vegetation.
Some specific situations carry higher risk:
- Walking off-trail through tall grass, ferns, or leaf litter in wooded areas
- Sitting on logs or the ground in shaded, humid spots
- Working along yard edges where lawn meets forest or thick shrubs
- Spending time near stone walls in the northeastern U.S., where tick-carrying rodents nest
- Handling or brushing against low vegetation during gardening, landscaping, or camping
Getting Ticks From Pets
Your dog or cat won’t transmit a tick-borne disease to you directly. But pets are effective tick shuttles. A dog running through the woods can pick up multiple ticks that later drop off inside your home, on furniture, or in bedding. Once indoors, those ticks can find their way to human skin. The CDC specifically notes that while pets don’t spread infections like Lyme disease to their owners, they do bring infected ticks into homes and yards.
Cats that roam outdoors present a similar risk, though they tend to groom ticks off themselves more effectively than dogs do. Either way, a pet returning from tick habitat is worth checking before it settles onto the couch.
When Tick Risk Is Highest
Tick activity follows a seasonal pattern tied to their life cycle. Eggs laid in spring hatch into larvae by summer. These tiny larvae (smaller than a poppy seed) feed on mice and small animals through late summer. By the following spring, they’ve molted into nymphs, which are the life stage most likely to bite humans and transmit disease. Nymphs are active from late spring through midsummer, roughly May through July in much of the U.S., and they’re small enough to go unnoticed on your skin for days.
Adult ticks become most active in fall and can remain active through winter on any day the temperature climbs above freezing. They’re larger and easier to spot, but they’re also actively questing for a blood meal before laying eggs in spring, completing the cycle.
Tick Range Is Expanding
If you live in an area where ticks weren’t a concern a decade ago, that may no longer be true. The geographic range of black-legged ticks has been steadily expanding, particularly along the Appalachian Mountains. A 2023 study tracking tick populations in North Carolina found that the leading edge of high-incidence areas moved 80 to 100 miles southwestward along the Blue Ridge Mountains over the study period. New counties in the western Piedmont region that previously had no established tick populations now do.
This expansion is driven in part by the movement of deer and other wildlife, warmer winters that allow ticks to survive in areas that were previously too cold, and the spread of tick populations from established zones in Virginia and the northeastern U.S. into new territory. The pattern suggests that tick habitat will continue pushing into regions that historically had low risk.
The Animals That Bring Ticks to You
White-tailed deer are the most visible tick hosts, and they’re the primary carriers of adult black-legged ticks. But white-footed mice may matter even more for disease transmission. Mice are the main reservoir for the bacteria that cause Lyme disease, and they’re the preferred host for larval and nymphal ticks. A single mouse can feed dozens of tick larvae, infecting many of them with disease-causing organisms in the process.
Other animals that carry ticks into residential areas include chipmunks, squirrels, raccoons, opossums, and ground-nesting birds. Any wildlife that moves between forested areas and your yard creates a bridge for ticks. This is why properties bordering woods or with features that attract small mammals tend to have higher tick densities, even if the lawn itself is well maintained.