Hoary Marmot
Encyclopedia
The hoary marmot is a species
of marmot
that inhabits the mountains of northwest North America
. Hoary marmots live near the tree line on slopes with grass
es and forb
s to eat and rocky areas for cover.
It is the largest North American ground squirrel
and is often nicknamed "the whistler" for its high-pitched warning issued to alert other members of the colony to possible danger. The animals are sometimes called "whistle pigs". Whistler, British Columbia
, originally London Mountain because of its heavy fogs and rain, was renamed for these animals to help make it more marketable as a resort. The closest relatives of the species are the Yellow bellied, Olympic
, and Vancouver Island marmot
s, although the exact relationships are unclear.
, with males being significantly larger than females in most subspecies. Because of their long winter hibernation
, during which they survive on fat reserves, the weight of the animals varies considerably over the course of the year, from an average of 3.75 kilograms (8.3 lb) in May to around 7 kilograms (15.4 lb) in September, for a fully grown adult.
The word hoary refers to the silver-gray fur on their shoulders and upper back; the remainder of the upper parts have drab brown or reddish brown fur. The head is black on the upper surface, with a white patch on the muzzle, white fur on the chin and around the lips, and grizzled black or brown fur elewhere. The feet and lower legs are black, sometimes with white patches on the forefeet. Marmots have long guard hair
s that provide most of the visible colour of their pelage
, and a dense, soft underfur that provides insulation. The greyish underparts of the body lack this underfur, and are more sparsely haired than the rest of the body. Hoary marmots moult in the early to mid summer.
The feet have slightly curved claws, which are somewhat larger on the fore feet than on the hind feet. The feet have hairless pads, enhancing their grip. The tail is long, slightly flattened, and covered with dense fur. Apart from the larger size of the former, males and females have a similar appearance. Females have five pairs of teats, running from the pectoral to the inguinal regions.
The hoary marmot inhabits mountainous environments from sea level to 2500 metres (8,202.1 ft) elevation, through much of Alaska
, western Canada
, and the extreme northwest of the contiguous United States
. They live above the tree line, at elevations from sea level to 2500 metres (8,202.1 ft), depending on latitude, in rocky terrain or alpine meadows dominated by grasses, sedges, herbs, and Krummholz
forest patches. Fossils are known dating back to the Pleistocene
, including some from islands no longer inhabited by the species.
There are currently three recognised subspecies:
, subsisting on leaves, flowers, grasses, and sedges. Predators include golden eagles
, grizzly
and black bears
, wolves
, coyote
s, red fox
es, lynxes, cougars and wolverine
s. They live in colonies of up to 36 individuals, with a home range
averaging about 14 hectares (34.6 acre). Each colony includes a single, dominant, adult male, up to three adult females, sometimes with a subordinate adult male, and a number of young and sub-adults up to two years of age.
The marmots hibernate
seven to eight months a year in burrow
s that they excavate in the soil, often among or under boulders. Each colony typically maintain a single hibernaculum
and a number of smaller burrows, used for sleeping and refuge from predators. The refuge burrows are the simplest and most numerous type of burrow, consisting of a single bolt hole 1 to 2 m (3.3 to 6.6 ) deep. Each colony of hoary marmots digs an average of five such burrows a year, and a mature colony may have over a hundred. Sleeping burrows and hibernacula are larger and more complex, with multiple entrances, deep chambers lined with plant material, and stretching to a depth of about 3.5 metres (11.5 ft). A colony may have up to nine regular sleeping burrows, in addition to the larger hibernaculum.
Many forms of social behaviour have been observed among hoary marmots, including play fighting, wrestling, social grooming, and nose-to-nose touching. Such activity becomes particularly frequent as hibernation approaches. Interactions with individuals from other colonies are less common, and usually hostile, with females chasing away intruders. Hoary marmots are also vocal animals, with at least seven distinct types of call, including chirps, whistles, growls, and whining sounds.. Many of these calls are used as alarms, alerting other animals to be alert for potential predators. They also communicate using scent, both by defecation, and by marking rocks or plants using scent gland
s on their cheeks.
Hoary marmots frequently sun themselves on rocks, spending as much as 44% of their time in the morning doing so, although they will shelter in their burrows or otherwise seek shade in especially warm weather. They forage for the rest of the day, returning to their burrows to sleep during the night.
In areas frequented by people, hoary marmots are not shy. Rather than running away at first sight, they will often go about their business while being watched.
Mating occurs after hibernation and two to four young are born in the spring. Males establish "harems," but may also visit females in other territories.
Gestation lasts 25 to 30 days, so that the litter of two to five young is born between late May and mid June. The young emerge from their birth den at three to four weeks of age, by which time they have a full coat of fur and are already beginning to be weaned
. The young are initially cautious, but begin to exhibit the full range of non-reproductive adult behaviour within about four weeks of emerging from the burrow. Sub-adults initially remain with their birth colony, but typically leave at two years of age, becoming fully sexually mature the following year.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of marmot
Marmot
The marmots are a genus, Marmota, of squirrels. There are 14 species in this genus.Marmots are generally large ground squirrels. Those most often referred to as marmots tend to live in mountainous areas such as the Alps, northern Apennines, Eurasian steppes, Carpathians, Tatras, and Pyrenees in...
that inhabits the mountains of northwest North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. Hoary marmots live near the tree line on slopes with grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
es and forb
Forb
A forb is a herbaceous flowering plant that is not a graminoid . The term is used in biology and in vegetation ecology, especially in relation to grasslands and understory.-Etymology:...
s to eat and rocky areas for cover.
It is the largest North American ground squirrel
Ground squirrel
The ground squirrels are members of the squirrel family of rodents which generally live on or in the ground, rather than trees. The term is most often used for the medium-sized ground squirrels, as the larger ones are more commonly known as marmots or prairie dogs, while the smaller and less...
and is often nicknamed "the whistler" for its high-pitched warning issued to alert other members of the colony to possible danger. The animals are sometimes called "whistle pigs". Whistler, British Columbia
Whistler, British Columbia
Whistler is a Canadian resort town in the southern Pacific Ranges of the Coast Mountains in the province of British Columbia, Canada, approximately north of Vancouver...
, originally London Mountain because of its heavy fogs and rain, was renamed for these animals to help make it more marketable as a resort. The closest relatives of the species are the Yellow bellied, Olympic
Olympic Marmot
The Olympic marmot, Marmota olympus, is a marmot . They are found in alpine and subalpine meadows and talus slopes on the Olympic Peninsula in the U.S. state of Washington, and are close relatives of the hoary marmot.Like most marmots, they are gregarious burrowing animals...
, and Vancouver Island marmot
Vancouver Island Marmot
The Vancouver Island marmot naturally occurs only in the high mountains of Vancouver Island, in British Columbia, Canada. This particular marmot species is large compared to some other marmots, and most other rodents...
s, although the exact relationships are unclear.
Description
The hoary marmot is a large, bulky, ground squirrel, with short, heavy limbs, and a broad head. Adults range from 62 to 82 cm (24.4 to 32.3 ) in total length, including a 17 to 25 cm (6.7 to 9.8 ) tail. The species is sexually dimorphicSexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
, with males being significantly larger than females in most subspecies. Because of their long winter hibernation
Hibernation
Hibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food supplies are limited, tapping energy reserves, body fat, at a slow rate...
, during which they survive on fat reserves, the weight of the animals varies considerably over the course of the year, from an average of 3.75 kilograms (8.3 lb) in May to around 7 kilograms (15.4 lb) in September, for a fully grown adult.
The word hoary refers to the silver-gray fur on their shoulders and upper back; the remainder of the upper parts have drab brown or reddish brown fur. The head is black on the upper surface, with a white patch on the muzzle, white fur on the chin and around the lips, and grizzled black or brown fur elewhere. The feet and lower legs are black, sometimes with white patches on the forefeet. Marmots have long guard hair
Guard hair
Guard hairs are the longest, coarsest hairs in a mammal's coat, forming the topcoat . They taper to a point and protect the undercoat from the elements. They are often water repellent and stick out above the rest of the coat...
s that provide most of the visible colour of their pelage
Fur
Fur is a synonym for hair, used more in reference to non-human animals, usually mammals; particularly those with extensives body hair coverage. The term is sometimes used to refer to the body hair of an animal as a complete coat, also known as the "pelage". Fur is also used to refer to animal...
, and a dense, soft underfur that provides insulation. The greyish underparts of the body lack this underfur, and are more sparsely haired than the rest of the body. Hoary marmots moult in the early to mid summer.
The feet have slightly curved claws, which are somewhat larger on the fore feet than on the hind feet. The feet have hairless pads, enhancing their grip. The tail is long, slightly flattened, and covered with dense fur. Apart from the larger size of the former, males and females have a similar appearance. Females have five pairs of teats, running from the pectoral to the inguinal regions.
Distribution and habitat
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
, western Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, and the extreme northwest of the contiguous United States
Contiguous United States
The contiguous United States are the 48 U.S. states on the continent of North America that are south of Canada and north of Mexico, plus the District of Columbia....
. They live above the tree line, at elevations from sea level to 2500 metres (8,202.1 ft), depending on latitude, in rocky terrain or alpine meadows dominated by grasses, sedges, herbs, and Krummholz
Krummholz
Krummholz or Krumholtz formation — also called Knieholz — is a particular feature of subarctic and subalpine tree line landscapes. Continual exposure to fierce, freezing winds causes vegetation to become stunted and deformed...
forest patches. Fossils are known dating back to the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
, including some from islands no longer inhabited by the species.
There are currently three recognised subspecies:
- Marmota caligata caligata - Alaska, YukonYukonYukon is the westernmost and smallest of Canada's three federal territories. It was named after the Yukon River. The word Yukon means "Great River" in Gwich’in....
, NW Territories, northern British ColumbiaBritish ColumbiaBritish Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858... - Marmota caligata cascandensis - Cascade Mountains, from British Columbia to Washington
- Marmota caligata okanagana - Rocky MountainsRocky MountainsThe Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
, from Yukon to MontanaMontanaMontana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
and IdahoIdahoIdaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
Behaviour and diet
Hoary marmots are diurnal and herbivorousHerbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
, subsisting on leaves, flowers, grasses, and sedges. Predators include golden eagles
Golden Eagle
The Golden Eagle is one of the best known birds of prey in the Northern Hemisphere. Like all eagles, it belongs to the family Accipitridae. Once widespread across the Holarctic, it has disappeared from many of the more heavily populated areas...
, grizzly
Brown Bear
The brown bear is a large bear distributed across much of northern Eurasia and North America. It can weigh from and its largest subspecies, the Kodiak Bear, rivals the polar bear as the largest member of the bear family and as the largest land-based predator.There are several recognized...
and black bears
American black bear
The American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...
, wolves
Gray Wolf
The gray wolf , also known as the wolf, is the largest extant wild member of the Canidae family...
, coyote
Coyote
The coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...
s, red fox
Red Fox
The red fox is the largest of the true foxes, as well as being the most geographically spread member of the Carnivora, being distributed across the entire northern hemisphere from the Arctic Circle to North Africa, Central America, and the steppes of Asia...
es, lynxes, cougars and wolverine
Wolverine
The wolverine, pronounced , Gulo gulo , also referred to as glutton, carcajou, skunk bear, or quickhatch, is the largest land-dwelling species of the family Mustelidae . It is a stocky and muscular carnivore, more closely resembling a small bear than other mustelids...
s. They live in colonies of up to 36 individuals, with a home range
Home range
Home range is the area where an animal lives and travels in. It is closely related to, but not identical with, the concept of "territory".The concept that can be traced back to a publication in 1943 by W. H. Burt, who constructed maps delineating the spatial extent or outside boundary of an...
averaging about 14 hectares (34.6 acre). Each colony includes a single, dominant, adult male, up to three adult females, sometimes with a subordinate adult male, and a number of young and sub-adults up to two years of age.
Hibernation
Hibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food supplies are limited, tapping energy reserves, body fat, at a slow rate...
seven to eight months a year in burrow
Burrow
A burrow is a hole or tunnel dug into the ground by an animal to create a space suitable for habitation, temporary refuge, or as a byproduct of locomotion. Burrows provide a form of shelter against predation and exposure to the elements, so the burrowing way of life is quite popular among the...
s that they excavate in the soil, often among or under boulders. Each colony typically maintain a single hibernaculum
Hibernaculum (zoology)
Hibernaculum plural form: hibernacula is a word used in zoology to refer to a place of abode in which a creature seeks refuge, such as a bear using a cave to overwinter. Insects may hibernate to survive the winter. The word can be used to describe a variety of shelters used by various kinds of...
and a number of smaller burrows, used for sleeping and refuge from predators. The refuge burrows are the simplest and most numerous type of burrow, consisting of a single bolt hole 1 to 2 m (3.3 to 6.6 ) deep. Each colony of hoary marmots digs an average of five such burrows a year, and a mature colony may have over a hundred. Sleeping burrows and hibernacula are larger and more complex, with multiple entrances, deep chambers lined with plant material, and stretching to a depth of about 3.5 metres (11.5 ft). A colony may have up to nine regular sleeping burrows, in addition to the larger hibernaculum.
Many forms of social behaviour have been observed among hoary marmots, including play fighting, wrestling, social grooming, and nose-to-nose touching. Such activity becomes particularly frequent as hibernation approaches. Interactions with individuals from other colonies are less common, and usually hostile, with females chasing away intruders. Hoary marmots are also vocal animals, with at least seven distinct types of call, including chirps, whistles, growls, and whining sounds.. Many of these calls are used as alarms, alerting other animals to be alert for potential predators. They also communicate using scent, both by defecation, and by marking rocks or plants using scent gland
Scent gland
Scent glands are found in the genital area of most mammals and in various other parts of the body, such as the underarms of humans and the preorbital glands of deer and muskox. They produce a semi-viscous fluid which contains pheromones. These odor-messengers indicate information such as status,...
s on their cheeks.
Hoary marmots frequently sun themselves on rocks, spending as much as 44% of their time in the morning doing so, although they will shelter in their burrows or otherwise seek shade in especially warm weather. They forage for the rest of the day, returning to their burrows to sleep during the night.
In areas frequented by people, hoary marmots are not shy. Rather than running away at first sight, they will often go about their business while being watched.
Mating occurs after hibernation and two to four young are born in the spring. Males establish "harems," but may also visit females in other territories.
Reproduction
Hoary marmots breed shortly after, or even before, their emergence from hibernation burrows in May. Courtship consists of sniffing the genital region, followed by mounting, although mounting has also been observed between females. Females typically raise litters only in alternate years, although both greater and lesser frequencies have been reported on occasion.Gestation lasts 25 to 30 days, so that the litter of two to five young is born between late May and mid June. The young emerge from their birth den at three to four weeks of age, by which time they have a full coat of fur and are already beginning to be weaned
Weaning
Weaning is the process of gradually introducing a mammal infant, either human or animal, to what will be its adult diet and withdrawing the supply of its mother's milk.The process takes place only in mammals, as only mammals produce milk...
. The young are initially cautious, but begin to exhibit the full range of non-reproductive adult behaviour within about four weeks of emerging from the burrow. Sub-adults initially remain with their birth colony, but typically leave at two years of age, becoming fully sexually mature the following year.