Winter Tick


winter / moose tick


  • Dermacentor albipictus
  • Winter tick
  • Moose tick


Female: Brown with white dorsal shield

Male: Brown with white crosshatched

Size: ¼” and long

Winter ticks are similar in size and appearance to the American dog tick.

The larvae are brown, about the size of a pinhead.

Adult winter ticks look like slightly elongated versions of the American dog tick.


Winter ticks are most commonly encountered in fall and winter. They are dormant in the summer and quest in the fall. Their preferred hosts are moose and other ungulates, including deer, elk, and caribou, and occasionally horses and cattle. Heavy infestations on an individual can result in severe anemia, skin irritation, hair loss, and distraction from feeding, and ultimately results in death.

The winter tick completes its entire development on one host. It is often found on moose, deer, or horses during the fall, winter or spring. Eggs of this species hatch in the spring, but the larvae remain bunched together, inactive, all summer long. They don’t become active until cold weather returns in the fall. As with other ticks, they wait on leaf litter or low vegetation for a host to brush by. After attaching to a suitable host, this species remains on the animal, feeding and molting until it has fully grown. Then it drops off, and eggs are laid on the ground in the spring.

Winter ticks are more abundant farther north in New Hampshire.


Moose Study


Winter tick doesn’t commonly bite people, and does not transmit agents that cause disease. Winter ticks kill moose because there are so many of them they are weakening the moose by extreme loss of blood causing anemia. Sometimes moose are found in winter with large patches of bare skin, carrying thousands of winter ticks. Such heavy infestations sometimes kill the moose. Recent research in New Hampshire demonstrates that winter ticks are limiting the moose population, and mortality of calves is especially high.

When a dead moose is discovered it has an average of 47,000 ticks that make them anemic. Calves are especially prone. Climate change is the key driver with shorter warmer winters giving them more changes for eggs to survive rather than freeze and longer fall to extend questing period.

Learn more about tick-borne diseases on our Diseases Page →