Marmota caligata

Hoary Marmots prefer treeless meadows with rocky outcrops and talus. They forage on forbs, grasses, and sedges. They tend to be gregarious. Groups of 5-8 feed together, with frequent bouts of greeting and grooming. As soon as they emerge from hibernation, in May, they mate. The young-of-the-year appear aboveground in July and have a short first year of activity. In September they disappear into hibernation, not to emerge until the following spring. The marmots become sexually mature when they are three years old, and from then on, females usually have a litter of 2-4 every other summer.

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Mammal Species of the World

This species occurs from Alaska in the United States, southward through British Columbia, Yukon Territory, Northwest Territory and Alberta in Canada, to Washington, Idaho, and Montana in the United States. Although mostly montane in distribution, it occurs down to sea level in northern Alaska.

Hoary marmots are one of the most widespread alpine mammals in North America, ranging from Alaska south through northwest Canada to Washington, Idaho, and Montana (Karels et al. 2004). They have a wide distribution in Alaska, including the Alaska Peninsula, Alaska Range, and White Mountains. In Canada, hoary marmots inhabit the Ogilvie Mountains in the Yukon Territory. They are found in the Cascades Mountain range, northern and central Rocky Mountains, the Beaverhead and Flint Creek Mountains of northwestern Montana, and the Salmon River mountains of central Idaho (Hoffmann et al. 1979).

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Alaska to Yukon and Northwest Territories, south to northeastern Washington, central Idaho, western Montana.

Hoary marmots weigh 8 to 10 kg and are from 45 to 57 cm in length, with males being slightly larger than females (Kyle et al. 2007). Tail length is 7 to 25 cm. Their coats are mostly black and white with hoary tips to the fur, base fur color varies geographically (Barash 1989, Hoffmann et al. 1979). They have a white patch between the eyes and across the rostrum, and the tips of their noses are white.  Hoary marmots differ from other marmots in that they have black feet. This is the basis of the species’ name caligata, which means “booted” (Hoffmann et al. 1979). They also have a black cap on their head that is larger than similar caps found in other species of marmots.  Marmots generally undergo a single annual molt. The onset of the molt varies, but can happen as soon as emergence from hibernation. By midsummer, molting is advanced in all individuals except the young of the year (Barash 1989). Hoary marmots have small eyes and small, rounded, furred ears. They have well-developed claws on their front feet for burrowing and 5 pats on their forepaws, 6 on their hind paws.

Range mass: 8 to 10 kg.

Average length: 50 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger

Length: 82 cm

Weight: 9000 grams

Sexual Dimorphism: Males are larger than females.

Length:
Range: 625-850 mm

Weight:
Range: 5-6 kg

Habitat and Ecology

Systems

• Terrestrial

Hoary marmots occupy areas with rocky talus slopes and alpine tundra vegetation (Kyle et al. 2007) and dig their burrows in these areas. Burrows provide shelter from predators and weather, marmots spend about 80% of their lives in them (Barash 1989). Entrances to marmot burrows are not easily identified because they simply appear as spaces between and/or under large boulders (Karels et al. 2004). The elevational range of hoary marmot habitats varies latitudinally; they are found at sea level in Alaska and only at higher elevations in the southern portions of their range.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: tundra ; mountains

Comments: Talus slopes and alpine or subalpine meadows. Young are born in underground burrows.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Hoary marmots are mostly herbivorous. Vetches, sedges, fleabanes, fescues, mosses, lichens, and willows collectively comprise about 90% of the overall diet of populations living on the Kenai Peninsula, while populations from mountainous regions prefer flowers and flower heads (Barash 1989, Hansen 1975). Marmot populations from different regions have similar diet-habitat characteristics even if less plant biomass is available. Hoary marmots do not select vegetation in proportion to the amount available, but rather show a preference for certain plants.  Hoary marmots spend most of their above-ground time foraging. They appear to prefer each other’s company, feeding in groups. Feeding groups of up to 8 animals can occur. However, these groups are loosely organized and dynamic in terms of membership (Barash 1989).

Plant Foods: leaves; flowers

Primary Diet: herbivore (Folivore )

Comments: Diet consists almost entirely of grasses and other herbaceous plants (Burt and Grossenheider 1976).

Hoary marmots are good candidates as indicator species because alpine ecosystems are particularly vulnerable to climate change (Krajick 2004). Compared to other alpine species, they have little commercial value in North America and hardly experience any human-related mortality. Changes in their populations could be indicative of other large-scale impacts. Long-term population dynamics of hoary marmots may also provide an indication of changes in alpine snowpack, plant phenology and abundance, or predators (Karels et al. 2004).

The feces of hoary marmots are important to pikas, which have been observed consuming these droppings. Dried fecal pellets of hoary marmots have been found in haypiles made by pikas (MacDonald and Jones 1987). Marmot feces may be important for soil as well. Soil surrounding marmot burrows is thought to be quite high in nutrients because marmots tend to deposit fecal matter in these areas (Bowman and Seastedt 2001).

Ecosystem Impact: soil aeration

Hoary marmots are eaten by a variety of predators, including golden eagles, lynx, coyotes, grizzlies, and wolverines. Predator avoidance appears to exert a strong influence on foraging patterns, and marmots have been known to remain in their burrows for many hours following the appearance of a predator (Barash 1989). They also use alarm calls to alert one another if a predator has entered their foraging area.

Known Predators:

• golden eagles (Aquila chrysaetos)
• lynxes (Lynx canadensis)
• coyotes (Canis latrans)
• grizzly bears (Ursus arctos)
• wolverines (Gulo gulo)

Hoary marmot alarm calls tend to be loud, relatively short, and are associated with predators or agitation (Barash 1989, Blumstein and Armitage 1997). Hoary marmots also use visual signals to communicate. The clearest visual signal is an upraised tail, which appears to signal aggression towards other members of the colony (Barash 1989).

Communication Channels: visual ; acoustic

Perception Channels: visual ; acoustic

Comments: Hibernates October-February in south, September-April in British Columbia (Whitaker 1980). Begins hibernation in mid-September in Alaska (Lee and Funderburg 1982).

Weight at hibernation is significantly related to overwinter mortality, which is highest among young of the year. Winter mortality during hibernation is often more predictable than predation, and the mortality of males is higher than that of females (Barash 1989).

Range lifespan
Status: captivity: 12.1 (high) years.

Maximum longevity: 12.1 years (captivity) Observations: One wild born specimen was about 12.1 years old when it died in captivity (Richard Weigl 2005). Maximum longevity could be underestimated, though.

Mating occurs shortly after emergence in the spring. Typical mating behavior involves the male approaching the female, sniffing her (possibly to determine if she is reproductive), then mounting her dorsoventrally. The female, when mounted, lifts her tail and holds it to one side. Successful mounts may last 30 seconds to 8 minutes. Non-reproductive females usually fight against an attempted mount, while reproductive females are more tolerant (Barash 1989). Sniffing, fighting, and chasing are all examples of marmot reproductive behavior. Originally, northern populations of hoary marmots were thought to be predominantly monogamous, while southern populations were thought to be both monogamous and polygynous. Recent studies suggest that mating among hoary marmots is more flexible than previously thought, varying between monogamy and polygyny. This may reflect local variation and resource availability (Kyle et al. 2007).

Mating System: monogamous ; polygynous

Females reproduce every other year, with an average litter size of 3.3, range 2 to 5 (Barash 1989, Armitage 2003). Yearlings remain in their natal colony and disperse the following year as two-year-olds, which is the age of sexual maturity. The reproductive cycle lasts 10 weeks, and gestation lasts about 4 weeks. Estrous in reproductive females occurs about 1 to 2 weeks after emergence from the hibernation and only occurs once yearly (Barash 1989).

Breeding interval: Hoary marmot females breed once every two years, although they go into estrous each year.

Breeding season: Hoary marmots breed in the early spring, shortly after emergence from hibernation.

Range number of offspring: 2 to 5.

Average number of offspring: 3.3.

Average gestation period: 4 weeks.

Average weaning age: 2 weeks.

Average time to independence: 2 years.

Average age at sexual or reproductive maturity (female): 2 years.

Average age at sexual or reproductive maturity (male): 2 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous

Average gestation period: 29 days.

Average number of offspring: 4.2.

Average age at sexual or reproductive maturity (female)
Sex: female: 908 days.

As the breeding season progresses, adult males and females become less closely associated. When the young of the year are born, females provide more parental care than males and are the most watchful during the two-week period of their young’s emergence (Barash 1989). Young of the year are born blind and naked, except for vibrissae and short hair on the muzzle, chin, and head. Crawling (backward and forward) and teat seeking are the first movements to occur (Armitage 2003). Young of the year are weaned between the third week of July and the first week of August. Even though adult males are larger than adult females, increases in size are relatively constant between sexes during development. Hair gradually develops from head to tail, and more rapidly on the back than on the belly (Armitage 2003).

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); post-independence association with parents

Gives birth to 4-5 young in late spring or early summer after gestation period of about 1 month (Whitaker 1980).

Year Assessed

Assessor/s

Reviewer/s

Justification

History

• 1996
  Lower Risk/least concern

Hoary marmots have a stable population trend and are considered a species of least concern. The state of Alaska, however, considers two subspecies of hoary marmots to be of conservation concern: Montague Island marmots (M. c. sheldoni) and Glacier Bay marmots (M. c. vigilis). Montague Island marmots were last seen at the turn of the 20th century and are considered a species of concern because of lack of sightings. Because these marmots are endemic to Montague Island, they may face a higher risk of extinction. The state of Alaska also considers Glacier Bay marmots to be a subspecies of concern due to its endemism and presumed small population size. In addition, there is lingering taxonomic uncertainty regarding both of these subspecies.

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Population

Population Trend

Major Threats

Conservation Actions

There are no known negative impacts associated with hoary marmots. Hoary marmots inhabit areas with low human population densities.

Hoary marmot hides were prized by northwestern Native Americans, mainly for clothing. Marmots were hunted after the molt, and their hides were used in potlatch ceremonies. Their hides were also used as a sort of currency, measuring wealth among Tlingit and Gitksan tribes (Armitage 2003).

Positive Impacts: food ; body parts are source of valuable material