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Dermacentor albipictus (Packard, 1869)
Horse Tick; Moose Tick; Winter Tick
Family: Ixodidae
Synonym(s): Scaphixodes albipictus


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Distribution of Dermacentor albipictus in British Columbia in British Columbia


The Moose Tick or Winter Tick is the most widely reported species of tick in British Columbia and one of the most widely distributed tick species in Canada (Lindquist et al. 2016). It primarily infests Moose and virtually all Moose are infested with this species of tick (Lindquist et al. 2016).

Biological information presented below is taken from Gregson (1956).

Species Information

Gregson (1956) describes this genus as follows: “Ornate ticks with eyes and festoons. Anal groove posterior to anus. Basiacapituli of adults rectangular (of nymphs, triangular or rectangular). Palpi short and broad or moderate in width. Coxae I to IV increasing in size progressively. Coxa I bifid. Males with no ventral plates.” This species resembles the Rocky Mountain wood tick (Dermacentor andersoni) in size and appearance (Higgins 1999). According to Gregson (1956), this species is variable in colour and sclerotization, and specimens from “Vancouver Island have spiracles much smaller than those of the mainland”. He indicates that the winter appearance is helpful in identification: “spiracles of the adults are typically rounded and divided into goblets much larger than those of D. andersoni. The basal capituli of the nymphs lack the sharp lateral points found in D. andersoni”.


Species Biology

According to Higgins (1999), this species is a serious pest of horses, sheep, cattle, moose and elk. He says “whereas one might occasionally find several Rocky Mountain Wood Ticks on a pet dog, it is normal to find 30,000 Winter Ticks on a single moose”. Gregson (1956) provides the following biological information for this species: “In nature moose and deer are the preferred hosts. Among domestic animals, horses often become severely infected, but cattle are seldom attacked ....This tick makes its appearance in late autumn, when clusters of up to 300 larvae gather on the ends of grasses and twigs. The larvae are remarkably tolerant of snow and cold and unless brushed onto a host may remain in position until spring. The larvae and nymphs remain on the host after engorging instead of dropping to the ground like most ticks. Usually ticks are not observed on horses until they are in their nymphal engorged state, when they are about the size of grains of rice and are blue-gray or dirty white in colour. The adults that emerge from these become fully engorged by early spring, when they are frequently confused with recently attached and engorging Dermacentor andersoni. Like andersoni, they drop to the ground to oviposit.”

Source: Gregson, John D. 1956. The Ixodoideae of Canada. Canada Deapartment of Agriculture, Ottawa


This species is associated with the habitat of its host.


Range in Canada and BC

There are collections for this species in BC from Campbell River, Wellington, Talta Lake, Quesnel, Upper Nechako, Clinton, Vavenby, and Newgate.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)

BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Synonyms and Alternate Names

Ixodes albipictus Packard, 1869

Species References

Gregson, John D. 1956. The Ixodoidae of Canada. Canada Department of Agricluture, Ottawa.

Lindquist, Evert E., Terry D. Galloway, Harvey Artsob, L. Robbin Lindsay, Michael Brebot, Heidi Wood and Richard. G. Robbins. 2016. A Handbook to the Ticks of Canada (Ixodida: Ixodidae, Argasidae Biological Survey of Canada, Ottawa