Marmota vancouverensis

Geographic Range

Vancouver Island marmots, Marmota vancouverensis , are endemic to Canada. They are found only on Vancouver Island, located in the south-western portion of Canada. Through extensive captive breeding and reintroduction programs, this species is now re-established on 27 mountains in south, central and northern Vancouver Island.

• Biogeographic Regions
• nearctic nearctic
  • native native

• Other Geographic Terms
• island endemic island endemic

Habitat

Vancouver Island marmots are found on south and west facing mountain ridges that are free of trees as a result of avalanches and snow accumulation during the winter months. Steep tree-less slopes allow for rapid snow melt in the spring, good visibility of predators, and excellent areas in which to "lounge" in order to thermoregulate. Vancouver Island marmots also inhabit mine tailings and meadows created by ski runs. They are found at at high elevations, from 900 to 1450 m above sea level.

Although rare, some marmots have been recorded at low elevations in suburban areas, such as back yards and in one case on a private dock. In general, the high amount of brush and trees makes lower elevations unsuitable habitat, and intensely forested landscapes do not contain the forbs and grasses necessary to the diet of Vancouver Island marmots.

Vancouver Island marmots require colluvial soil structure for their burrows, which are used to escape predators, overwinter and hibernate. Vancouver Island marmots require deep soil, as they burrow below the frost line during winter; winter temperatures within the hibernacula must be maintained at at least 5 °C. Higher elevations typically do not contain soil patches deep enough to construct proper burrows, while lower elevations are too heavily vegetated and warm. Burrows may be found at the base of tree trunks and large boulders where visibility is good. For this reason, newly clear-cut areas may be quickly colonized but do not support long term populations as a result of poor overwintering success and forest regeneration. Populations of Vancouver Island marmot are limited primarily by the availability of suitable habitat.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland
• mountains mountains

Physical Description

Vancouver Island marmots are semi-fossorial sciurids that differ from other marmots in their pelage coloration. Adults are a dark chocolate brown color and have characteristic irregular patches of white fur on their chest, chin, nose and forehead. Other closely related marmot species (hoary marmots Marmota ciligata and Olympic marmots Marmota olympus ) are tawny or grey colored, with no distinct white markings. The dorsal side of Vancouver Island marmots have white hairs interspersed, but with no prominent patterning.

Pups are born a uniform black-brown that fades to a reddish brown in the summer months. As this species does not complete a full molt every year, juveniles are easily identifiable by their mottled rust colour when compared to the darker, white marked adults. Molting occurs unevenly, beginning on the forelegs and shoulders and ending with the head, back and tail.

Mature Vancouver Island marmots measure between 56 and 70 cm from the nose to the tip of the tail. Their tails are bushy and covered with relatively coarse, long guard hairs. Their body is stout with short strong legs, and paws are pentadactyl, donned with robust fossorial claws for burrowing. Forepaws have two posterior pads and three anterior pads located at the base of the digits, while hind paws have two posterior pads and four anterior pads at the base of the digits. Posterior foot pads are circular, a trait that is shared with the closely related M. caligata and Marmota olympus . The head is broad and short, with relatively short ears located dorsolaterally, slightly posterior to the eyes. Adults weigh between 3 and 7 kg depending on sex and time of year. Males tend to weigh significantly more than females. Vancouver Island marmots weigh the most in mid-September, prior to hibernation.

Skull structure of Vancouver Island marmots is one of the strongest distinguishing feature of this species. The nasals are shorter than those found in other marmot species (41.5 mm +/- 0.7 mm) and have a v-shaped notch at the posterior border. Parietal bones are relatively narrow when compared with other Marmota sp., and the coronoid process has a distinct bend at its tip. Average condylobasal length is reported as 92.7 mm =/- 0.7 mm, with average width of rostrum of 21.8 mm +/- 0.3 mm, zygomatic width 60.7 mm +/- 0.6 mm, and interorbital width of 22.3 mm +/- 0.4 mm (n = 10 for all measurements). Average male cranial measurements are larger than females. Dental formula for the Vancouver Island Marmot is 1/1, 0/0, 2/2, 3/3 = 24. Incisors are prominent and typically pale to dark yellow on the labial side and lighter on the lingual side.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Reproduction

Small colonies consist of a single family group containing 1 male, 1 to 2 females, juveniles and young of the year. Vancouver Island marmots have a monogamous mating system, though males have been recording siring more than one litter in a single breeding season. Pairs breed for multiple years, with juveniles dispersing from the family colony between 2 and 3 years of age. Younger males are subordinate to older males, with females preferentially breeding with males 3 years of age or older. As females tend to live longer than males, the operational sex ratio is skewed toward older females.

As with many mammals, behavior associated with reproduction in Vancouver Island marmots corresponds with increased levels of reproductive hormones such as estrogen and progesterone in females and testosterone in males. Ovulation is induced through copulation, and an increase in play behaviour corresponds to frequent copulation; several attempts may be necessary for conception to occur. Because mating occurs within burrows, little is known regarding specific mating behaviors.

In captivity, female Vancouver Island marmots are more receptive to males they have had prolonged contact with, suggesting that the strength of the social system is integral in mating success. The relatively large distances between colonies (20 km^2) that has occurred as a result of recent population declines may be negatively impacting reproductive success due to a lack of access to potential mates.

• Mating System
• monogamous monogamous
• polygynous polygynous

Female Vancouver Island marmots reach reproductive maturity between the ages of 2 and 4. Females rarely raise pups at the age of 2, and most often raise their first litter of pups between the ages of 4 and 5. Mating occurs once a year in the early spring when snow melts and adults emerge from hibernation. While mating is seasonal, individual females rear young every 1 to 3 years. Females may give birth for the first time between the ages of 2 to 6. While males younger than 3 may be sexually mature, they rarely mate as they are subordinate to older males.

Vancouver Island marmots usually have litters of 3 to 4 pups, though litter size can range from 1 to 7. Litter size and success varies greatly from year to year, perhaps depending on food availability, female body condition, and weather. Past rearing of pups does not appear to influence survival of offspring. Females in the intermediate age class have a higher rate of reproductive success than young or old individuals, and older females also produce fewer offspring. Gestation lasts approximately 32 days, and pups are weaned at about 30 days of age. Weaning tends to occur at the beginning of July, when pups emerge from the burrows.

• Key Reproductive Features
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• induced ovulation induced ovulation
• viviparous viviparous

Parturition of Vancouver Island marmots occurs within burrow chambers in late May to early June. Pups remain underground where the mother nurses, emerging to forage. Males do not appear to play a direct role in care of the offspring, but do provide protection through vigilance to potential threats. Pups are weaned at about 30 days of age.

Vancouver Island marmot young of the year first emerge from their burrows in late June or early July. They remain near the natal burrow for their first year and often hibernate in the same burrow system as their mother. Pup mortality is generally low until hibernation, with the majority of mortality occurring over the winter. Females with young have significantly smaller home ranges than females who did not breed that year, indicating increased vigilance and preparedness to retreat to burrow systems. Adults with pups experience an increased risk of predation compared to adults that are without pups in the same breeding season.

• Parental Investment
• altricial altricial
• female parental care female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • female
• post-independence association with parents
• inherits maternal/paternal territory

Lifespan/Longevity

Vancouver Island marmots have an average lifespan of 10 years, with females typically living longer than males. Based on longevity of closely related marmot species, the maximum age of Vancouver Island marmots is estimated to be between 12 and 15 years. Average age of mortality due to predation is around 3 years, with the majority of these deaths occurring from August to September. The majority of pup mortality occurs over the first winter during hibernation. Annual survival rate of Vancouver Island marmots is 73%.

Behavior

Vancouver Island marmots live in small family colonies composed of 1 adult male, 1 to 2 adult females, varying numbers of juveniles and the young of the year. Each colony contains an average of 3.6 individuals. Subadult males disperse from the colony between 2 and 3 years of age, roaming between 20 and 50 km. Vancouver Island marmots spend much of their time alone, foraging and resting independently of other marmots. They spend less than 40% of their time within 100 m of other colony members.

Social hierarchies within a colony are established through agonistic behaviors such as lunging and chasing by dominant individuals and avoidance by subordinates. Play fighting and wrestling occurs most often in young and breeding pairs, while agonistic behaviors such as chasing and fighting occur between males in the breeding season and upon initial meetings. Play fighting, tail raising, mounting and allogrooming may also be indicative of social status within the colony. Adult males are dominant to adult females, followed by juvenile females. Vancouver Island marmots are territorial and mark territories with scent glands located in their cheeks. The majority of scent marking is done by adult males, though adult females also scent mark.

Daily activities of Vancouver Island Marmots include foraging, being vigilant, resting on rocks and logs, interacting with conspecifics, and spending time within burrows. Feeding typically occurs during the early morning and evening hours, with the rest of the day allocated primarily to lounging behavior and vigilance. Vigilance is described as when an individual lifts its head or stands on its hind legs in order to scan its surroundings. Resting includes the many hours that individuals spend lying on rocks or logs. As the summer progresses, marmots spend less time feeding, particularly when temperatures exceed 20 °C. Time spent in the burrow during the day is directly correlated with the daily maximum temperature.

Areas that are used for resting are typically exposed to the sun and have good visibility. Frequently used resting spots have distinct mud stains that the marmot leaves on the surface.

Vancouver Island marmots are semi-fossorial and spend a great deal of time underground in burrows. These burrows vary in size and use, but usually have an entrances that are 30 to 45 cm in diameter. Burrows used to escape from predators are typically shallow and small, located primarily beneath rocks and root systems. Burrows used for birthing and sleeping overnight may be deep and comparatively elaborate, with multiple entrances and deeper chambers. Sleeping chambers have been recorded to be as deep as 1 m underground. Chambers used for hibernation must be deep in order to stay below the frost layer. It is believed that these burrow systems are used by multiple individuals for a number of years.

Vancouver Island marmots hibernate from late September to late April in deep burrows containing a larger chamber filled with vegetative bedding. Family colonies hibernate together. The average number of individuals within a single hibernacula is 8, mostly containing pups and juveniles. To protect themselves from harsh weather, the entrance to the burrow is closed by piling up rocks and soil from inside the hibernacula prior to the onset of winter. At the onset of spring, the group emerges from their burrow and initiate extensive greeting and social behavior associated with dominance hierarchies.

• Key Behaviors
• terricolous
• fossorial fossorial
• diurnal diurnal
• motile motile
• sedentary sedentary
• hibernation hibernation
• social social

Home Range

The average home range of a Vancouver Island marmot has increased over the past 30 years, from approximately 30 m^2 to approximately 900 m^2. The average distance between colonies is 20 km^2. Males tend to have much larger home ranges than females, and males that hibernate alone have larger home ranges than those who hibernate with a female. Females that are weaning pups have the smallest home range, as they tend to stay close to their burrows for protection from predators.

Communication and Perception

Marmots are a social animal that communicate with one another through direct contact and whistling vocalizations. Vancouver Island marmots have an array of calls that are used to communicate potential danger to conspecifics. When a marmot produces a call, other marmots within the area become vigilant toward the threat. As with other marmot species, calls can be flat, trilled, and ascending or descending in tone; however this species has a characteristic "kee-aw" call not used by other marmots. Calls are not specific to terrestrial or aerial predators, though flat calls are more frequently used with terrestrial predators. Kee-aws are used when the threat is not intense or imminent, though it induces maintained vigilance in conspecifics. Trills are used most frequently during high threat interactions. Females with weaning pups are more likely to emit calls than other marmots, presumably to increase the vigilance of their offspring and relatives.

Vancouver Island marmots mark territories with scent glands located in their cheeks. The majority of scent marking is done by adult males, though adult females also scent mark.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic

• Other Communication Modes
• pheromones pheromones
• scent marks scent marks

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Vancouver Island marmots eat primarily grass and forbs that are found in subalpine meadows. They forage slowly across their home range, preferentially eating flowers, fruits and fresh buds. They also browse on fresh fiddleheads of bracken fern ( Pteridium aquilinum ). In the spring, grasses make up the majority of the diet, including oatgrass ( Danthonia intermedia ), woodrush ( Luzula ) and various sedges ( Carex ). Spreading phlox ( Phlox diffusa ) and lupine herbs ( Lupinus ) are consumed readily when present but are not as common as grasses at this time of year. Throughout the summer, meadowrue ( Thalictrum ), paintbrush ( Haemanthus ), cow parsnip ( Heracleum maximum ) and woolly sunflower ( Eriophyllum lanatum ) are consumed. By late summer, broad leaved herbs such as peavine ( Lathyrus ) and lupines make up the majority of the diet. Foraging occurs most often in the early morning and evening.

• Primary Diet
• herbivore herbivore
  • folivore folivore
  • frugivore frugivore

• Plant Foods
• leaves
• fruit
• flowers

Predation

Vancouver Island marmots are subject to strong predation pressure, with 83% of annual mortality resulting from predation. Death due to wolves account for 38%, cougars 21%, and golden eagles 14%. While no incidents have been recorded, it is likely that bald eagles occasionally prey upon marmots. Predators target adult marmots, and the majority of predation occurs in late summer, between August and September.

Between 1992 and 2007, the overall annual survival of adults marmots was 70.9%. This is much lower than then 80% survival rate necessary to sustain populations, indicating a steady decline. Survival rates of both adults and pups does not differ with age and sex.

The increase in home range size over the last 30 years likely makes these marmots more vulnerable to predation.

When a predator approaches, Vancouver Island marmots become vigilant and orient their body toward the threat at a distance of 50 m. Prior to emitting an alarm call, they retreat to locations near burrow entrances when the perceived threat is approximately 32 m away. A variety of alarm calls warn conspecifics of the threat.

Ecosystem Roles

As herbivores, Vancouver Island marmots may act as seed dispersers and pollinators for the variety of grasses and flowers that they consume; as they amble about subalpine meadows to forage, they may collect various pollens and disperse consumed seeds through their feces. Further, they build large burrow systems that may be used by other animals, including insects and small mammals.

Vancouver Island marmots are hosts to ticks ( Ixodes ) and fleas ( Thrassis spenceri ). Many trapped marmots are heavily infested, though parasite infestation does not seem to decrease their survival or fecundity. Vancouver Island marmots also act as hosts for the nematode Baylisascaris laevis . Interestingly, the cestode Diandrya vancouverensis is completely unique to Vancouver Island marmots. This tape worm is closely related to a mainland helminth found in Marmota olympus and may be an example of coevolution due to allopatric speciation.

The increase in predation and consequent decrease in marmot populations is believed to be an indirect result of a decrease in black-tailed deer ( Odocoileus hemionus columbianus) , the main prey of wolves and cougars . The small deer population has caused an increase in both wolf and cougar predation upon alternative food sources, which includes Vancouver Island marmots.

• Ecosystem Impact
• disperses seeds
• pollinates
• creates habitat
• soil aeration soil aeration

Economic Importance for Humans: Positive

The role of Vancouver Island marmots as prey for wolves and cougar may allow for higher populations of these fur bearing animals.

Economic Importance for Humans: Negative

There are no known adverse affects of Vancouver Island marmots on humans, as they live in remote areas at extremely low densities.

Conservation Status

First listed as endangered in 1978 and now critically endangered, Vancouver Island marmots are currently one of the rarest animals in North America. In 2004, it was estimated that only 35 individuals remained in the wild in an area less than 10 km². While these marmots have historically lived at low densities as a result of limited habitat and predation pressures, the recent sharp decline in numbers has been attributed to habitat loss from clear cut logging. While a temporary increase in population occurred as a result of logging in the 1980s - newly clear cut landscapes create ideal forage, burrow sites and visibility for marmots, - colonies that established in these areas vanished after a few years. Reforestation of these areas provided excellent cover for predators, and overwintering success was low. The population peaked at 300 to 350 marmots in 1984 before a drastic decline as a result of high mortality rates.

As opposed to even mortality across populations, it appears that entire colonies fail at one time, a trend consistent with intense predation, disease and poor hibernacula. Prior to reintroduction efforts, the population of Vancouver Island marmots declined more than 80% in 20 years, and extinction in the wild was imminent.

In 1998, the Marmot Recovery Foundation was established and 4 breeding programs were organized across Canada in an effort to reintroduce Vancouver Island marmots to the wild: the Calgary and Toronto zoos, Mountain View Conservation and Breeding Centre in Langley, BC and the Tony Barrett Mt Washington Marmot Recovery Centre on Vancouver Island. As of 2010, the program has been a success, with the wild population estimated to be about 300 individuals. Vancouver Island marmots now inhabit 27 mountains, compared with the 5 that were inhabited in 2003. The Recovery Strategy Goal is to have 600 marmots living in the wild in core populations in south, central and northern Vancouver Island.

Captive born individuals have successfully established colonies, surviving through the winter and producing pups. The second generation of pups from captive born marmots have successfully weaned in the wild. It is thought that several more years and a greater understanding of this species' ecology and behaviour is necessary to reach sustainable populations in the wild. Further conservation sites at marmot colonies are also sought after by the Marmot Recovery Foundation, which hopes to establish Wildlife Habitat Areas at colonization and reintroduction sites.

Other Comments

Additional information regarding reintroduction programs can be found at www.marmots.org .

Additional Links

Encyclopedia of Life

Contributors

Jacqueline Chapman (author), University of Manitoba, Jane Waterman (editor), University of Manitoba, Gail McCormick (editor), Animal Diversity Web Staff.

References

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Blumstein, D., B. Holland, J. Daniel. 2006. Predator discrimination and 'personality' in captive Vancouver Island marmots ( Marmota vancouverensis ). Animal Conservation , 9: 274-282.

Brashares, J., J. Werner, A. Sinclair. 2010. Social 'meltdown' in the demise of an island endemic: Allee effects and the Vancouver Island marmot. Journal of Animal Ecology , 79: 965-973.

Bryant, A., D. Blood. 1999. Vancouver Island Marmot: Species at Risk in British Columbia. Ministry of Environment, Lands and Parks (Victoria, BC): 1-6.

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Mace, T., C. Shepard. 1981. Helminths of a Vancouver Island marmot, Marmota vancouverensis Swarth, 1911, with a description of Diandrya vancouverensis sp.nov. (Cestoda: Anoplocephalidae). Canadian Journal of Zoology , 59: 790-792.

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Nagorsen, D. 1987. Marmota vancouverensis . Mammalian Species , 270: 1-5.

Thorington, R., R. Hoffman. 2005. Vancouver Island Marmot. Pp. 802-803 in Mammal Species of the World: A Taxonomic and Geographical Reference , Vol. 2, 3rd Edition Edition. Baltimore, Maryland: John Hopkins University Press.

2010. "Fall/Winter 2010 Newsletter" (On-line). Accessed October 14, 2011 at http://www.marmots.org .