Marmota caligata 275size: Both sexes—HB 450–600 mm; T 170–250 mm; Mass
3600–9000 g.
Males are larger than females.
distribution: This marmot ranges from the Yukon River
through central and southern Alaska (USA) and the Yukon
and Northwest Territories (Canada) south to Washington,
Idaho, and western Montana (USA).
geographic variation: Three subspecies are recognized.
M. c. caligata—western Yukon (Canada) and most of Alaska
south of the Yukon River, including Montague Island and
Glacier Bay (USA). See description above.
M. c. cascadensis—southern and western British Columbia
(Canada) and Washington (USA). The head and feet are
browner, and the underparts are darker.
M. c. okanagana—southern Yukon and the Northwest Terri-
tories into eastern British Columbia and western Alberta
(Canada) to Idaho and Montana (USA). This is a lighter-
colored form.
conservation: IUCN status—least concern. Population
trend—stable.
habitat: Hoary marmots inhabit open rocky talus slopes
and alpine tundra throughout their range. Such habitats are
often disjunct, so the distribution of M. caligata at local and
landscape scales is often fragmented.
natural history: Hoary marmots hibernate in burrows,
often as family groups, during the many months of the long
winters throughout their distribution. They emerge in late
spring, when females give birth to a litter of four to fi ve
young; litters are produced every two years. They feed in
open meadows on grasses and herbaceous species during
the growing season; their large gut capacity permits them to
exist on even low-quality forage. They communicate by
scent-marks and vocalizations. These vocalizations primar-
ily convey information on predation risks, and their calls
diff er for aerial and terrestrial predators. Hoary marmots
are highly social; they typically exist in family groups com-
posed of a dominant male, adult female(s), yearlings, young-
of-the-year, and subordinate males on the periphery of the
dominant male’s home range. Dominant females appear to
suppress the reproductive activity of other adult female
colony members. The mating system appears to be faculta-
tive, with monogamy and polygyny observed within a col-
ony, although polygyny appears to be more common in theMarmota caligata. Photo courtesy U.S. Fish and Wildlife
Service.