Marmota flaviventris is a species of ground squirrel found in certain higher elevation parts of western North America, occurring chiefly in meadows and open areas adjacent to woodlands. This species constructs a burrow for colonial living and enters hibernation near the onset of winter.
Native distribution includes portions of Western North America (Frase & Hoffman. 1980) from south-central British Columbia and southern Alberta in Canada to the southern Sierra Nevada and White Mountains of southern California, Nevada, southern Utah, and the Sangre de Cristo Mountains in northern New Mexico. M. flaviventris typically occurs higher than 2000 meters in elevation. Because this species is restricted to higher elevations, it is frequently absent from valleys intervening between montane habitats. Correspondingly many populations of M. flaviventris are isolated from each other. (Blumstein et al. 2006)
Marmota flaviventris is a small to medium-size rodent species, with yellowish tint to its fur on the undersides. The male has a body mass from 2.9 to 5.2 kilograms, with sexual dimorphism that features smaller females of body mass ranging from 1.6 to 3.6 kilograms. Adult body length ranges from 47 to 70 centimeters, with the females occupying the end of that range; adult tail length is typically 13 to 22 centimeters, again with females being on the lower end of the range. Each foot has five digits, an oval pad lying in the center of the sole of the hind foot; claws are abbreviated in length and somewhat curved with a rudimentary nail-bearing thumb.
This species exhibits a broad head that features a narrow interorbital region, with temporal ridges that join to create a low, short, sagittal crest. The posterior end of the palate lies obtusely; moreover, teeth of the upper jaw are positioned somewhat more anterior than those of the lower jaw. M. flaviventris exhibits smallish furry ears.
Habitat and behavior
Preferred habitat for this rodent includes high altitude meadows, especially at ecotones involving a forest edge or talus edge. The typical altitude range of this species is above 2000 meters above sea level. Burrows are usually constructed in soils that are below boulders or rock piles including talus edges; this technique is utilized in order to make the burrow less accessible to predators. Natural predators are coyote, wolf, badger, American eagle, black bear and fox; when M. flaviventris senses a predator or human nearby, it often vocalizes with a whistle sound, warning other members of its colony.
Colony sizes generally range from eight to 24 individuals, although some burrows are inhabited by only an adult pair, or in some cases even a sole individual. A typical colony includes one territorial male, one to four adult female mates and three to twenty juveniles. (Armitage. 2004) In some cases more than one adult male will be present in a single colony.
This marmot is an omnivore, and consumes a broad variety of forbs, grasses, insects and even bird eggs; among the forbs and shrubs, it may eat both leaves and berries.
M. flaviventris typically enters hibernation in an underground burrow prior to the onset of winter. It emerges from hibernation in the spring, with lower elevation populations emerging in the earlier parts of spring. Mating begins within several weeks of emergence from hibernation. Gestation is generally around thirty days, with the female producing a litter of three to eight offspring. Birthing occurs in the burrows, where the young remain for about another twenty to thirty days.
This taxon is designated as of Least Concern as a conservation risk by the IUCN owing to its relative abundance throughout much of its range. (Lindzey & Hammerson. 2008) There are no major threats to this species from a conservation standpoint.
- A. V. Lindzey and G. Hammerson. 2008. Marmota flaviventris. In: IUCN. 2008. IUCN Red List of Threatened Species.
- B. Frase and R. Hoffmann. 1980. Marmota flaviventris. Mammalian Species, No. 135: 1-8
- C.Michael Hogan. 2012. ''Species account for Marmota flaviventris". Globaltwitcher. ed. N.Stromberg
- D. Blumstein, A. Ozgu, V. Yovovich. 2006. Effect of predation risk on the presence and persistence of yellow-bellied marmot (Marmota flaviventris) colonies. Journal of Zoology, v. 270 no. 1: 132-138.
- K. Armitage. 2004. Badger Predation on Yellow-bellied Marmots. The American Midland Naturalist, v. 151 no. 2: 378-387.
Mammal Species of the World
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- Original description: Audubon, J. J., and J. Bachman, 1841. Descriptions of new species of quadrupeds inhabiting North America, p. 29. Journal of the Academy of Natural Sciences of Philadelphia, series 1, 8:1-43.
Yellow-bellied marmots are distributed widely in the western United States and Canada. They range as far north as southcentral British Columbia and Alberta in Canada and as far south as the Sierra Nevada.
Biogeographic Regions: nearctic (Native )
- Frase, B., R. Hoffmann. 1980. Marmota flaviventris. Mammalian Species, No. 135: 1-8. Accessed February 23, 2011 at http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-135-01-0001.pdf.
occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Year-round
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: Range includes western North America from south-central British Columbia and southern Alberta southward to southern California, Nevada, southern Utah, and the Sangre de Cristo Mountains in northern New Mexico, typically at elevations above 2,000 meters.
Yellow-bellied marmots are a small to medium-sized rodents. Males weigh from 2.95 to 5.22 kg, with an average of 3.9 kg. Females range in mass from 1.59 to 3.57 kg, with an average of 2.8 kg. Total length ranges from 470 to 700 mm, with tail length ranging from 130 to 220 mm. Hind-foot length from 70 to 90 mm, and condylobasal length ranges from 68.0 to 99.8 mm. Males are longer than females and weigh significantly more. Also, individuals from low, arid-land habitats tend to be smaller than those from mesic, montane habitats. They have robust bodies, with short and broad heads. The head has a narrow interorbital region, with temporal ridges brought joining to form a low, short, sagittal crest. The posterior end of the palate lies obtusely, and the teeth of the upper jaw lie slightly more anterior than the teeth of the bottom jaw. The dental formula is 1/1, 0/0, 2/1, 3/3 = 22. The cheek teeth are high-crowned. Yellow-bellied marmots have small, well-furred ears, feet with five digits and an oval pad in the center of the sole of the hind foot, short and slightly curved claws with a rudimentary nail-bearing thumb, and ten mammae – two pectoral, two abdominal, and one inguinal pair.
The underfur of yellow-bellied marmots is soft, dense, and wooly on the back and sides of the body. Longer, coarse outer guard hairs with lighter tips and darker bases cover the entire body, making the overall color yellow-brown to tawny. Individuals are rarely dark brown and never black, except in melanistic individuals (common in populations in southern Rocky Mountains). There are also noticeable buffy yellowish patches on the side of the neck, white spots between the eyes, and a yellow or orange-russet color covering the belly, with feet a buffy, hazel, or dark brown color. There is great variety in color within subspecies. Yellow-belied marmots molt once annually during summer.
Range mass: 1.59 to 5.22 kg.
Average mass: 3.35 kg.
Range length: 470 to 700 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Average basal metabolic rate: 8.626 W.
Length: 70 cm
Weight: 4500 grams
Size in North America
Average: 618 mm males; 574 mm females
Range: 490-618 mm males; 470-670 mm females
Range: 3-5.2 kg males; 1.6-4 kg females
Colorado Plateau Shrublands Habitat
This taxon can be found in the Colorado Plateau shrublands, as one of its North American ecoregions of occurrence. The Plateau is an elevated, northward-tilted saucer landform, characterized by its high elevation and arid to semi-arid climate. Known for the Grand Canyon, it exhibits dramatic topographic relief through the erosive action of high-gradient, swift-flowing rivers that have downcut and incised the plateau. Approximately 90 percent of the plateau is drained by the Colorado River and its tributaries, notably the lower catchment of the Green River.
A pinyon-juniper zone is extensive, dominated by a pygmy forest of Pinyon pine (Pinus edulis) and several species of juniper (Juniperus spp). Between the trees the ground is sparsely covered by grama, other grasses, herbs, and various shrubs, such as Big sagebrush (Artemisia tridentata) and Alder-leaf cercocarpus (Cercocarpus montanus).
A montane zone extends over large areas on the high plateaus and mountains, but is much smaller than the pinyon-juniper zone. The montane vegetation varies considerably, from Ponderosa pine in the south to Lodgepole pine and Aspen further north. Northern Arizona contains four distinct Douglas-fir habitat types. The lowest zone has arid grasslands but with many bare areas, as well as xeric shrubs and sagebrush. Several species of cacti and yucca are common at low elevations in the south.
Numerous mammalian species are found within the Colorado Plateau shrublands ecoregion, including the Black-tailed prairie dog (Cynomys ludovicianus); Long-eared chipmunk (Tamias quadrimaculatus); Utah prairie dog (Cynomys parvidens EN); Yellow-bellied marmot (Marmota flaviventris); and the Uinta chipmunk (Tamias umbrinus), a burrowing omnivore.
A large number of birds are seen in the ecoregion, with representative taxa: Chestnut-collared longspur (Calcarius ornatus NT); Greater sage grouse (Centrocercus urophasianus NT); Northern pygmy owl (Glaucidium gnoma); Cactus wren (Campylorhynchus brunneicapillus).
There are various snakes occurring within the Colorado Plateau, including: Black-necked garter snake (Thamnophis cyrtopsis), usually found in riparian zones; Plains Blackhead snake (Tantilla nigriceps); Black-tailed rattlesnake (Crotalus molossus), who seeks inactivity refuge in rock crevices, animal burrows and even woodrat houses. Other reptiles found here include the Common checkered whiptail (Cnemidophorus tesselatus).
There are only a limited number of anuran taxa on the Colorado Plateau; in fact, the comprehensive occcurrence list for the ecoregion is: Red-spotted toad (Anaxyrus punctatus); Canyon treefrog (Hyla arenicolor); Woodhouse's toad (Anaxyrus woodhousii); Couch's spadefoot toad (Scaphiopus couchii); Northern leopard frog (Lithobates pipiens); Plains spadefoot toad (Spea bombifrons); and Southwestern toad (Anaxyrus microscaphus). The Tiger salamander (Ambystoma tigrinum) is the sole salamander found on the Colorado Plateau shrublands.
The Colorado River fish fauna display distinctive adaptive radiations. The Humpback chub (Gila cypha), for example, is a highly specialized minnow that lives in the upper Colorado. It adapted to the water’s fast current and its extremes of temperature and flow rate. Dams and water diversion, however, have created a series of placid, stillwater lakes and side streams, and the Humpback chub may not be able to adapt to these altered conditions. The species, along with other native Colorado River fishes including the Bonytail (Gila elegans), Squawfish (Ptychocheilus lucius), and the Flannelmouth sucker (Catostomus latipinnis), may not survive much further in time.
- C. Michael Hogan & World Wildlife Fund. 2014."Colorado Plateau shrublands". Encyclopedia of Earth, National Council for Science and the Environment, Washington DC ed.Mark McGinley.
- Michael G. Barbour and William Dwight Billings. 2000. North American Terrestrial Vegetation. Cambridge University Press. ISBN 0-521-55986-3.
- Taylor H. Ricketts. 1999. Terrestrial ecoregions of North America: a conservation assessment. 485 pages
Palouse Grasslands Habitat
This taxon is found in the Palouse grasslands, among other North American ecoregions. The Palouse ecoregion extends over eastern Washington, northwestern Idaho and northeastern Oregon. Grasslands and savannas once covered extensive areas of the inter-mountain west, from southwest Canada into western Montana in the USA. Today, areas like the great Palouse prairie of eastern are virtually eliminated as natural areas due to conversion to rangeland. The Palouse, formerly a vast expanse of native wheatgrasses (Agropyron spp), Idaho Fescue (Festuca idahoensis), and other grasses, has been mostly plowed and converted to wheat fields or is covered by Drooping Brome (Bromus tectorum) and other alien plant species.
the Palouse historically resembled the mixed-grass vegetation of the Central grasslands, except for the absence of short grasses. Such species as Bluebunch Wheatgrass (Elymus spicatus), Idaho Fescue (Festuca idahoensis) and Giant Wildrye (Elymus condensatus) and the associated species Lassen County Bluegrass (Poa limosa), Crested Hairgrass (Koeleria pyramidata), Bottlebrush Squirrel-tail (Sitanion hystrix), Needle-and-thread (Stipa comata) and Western Wheatgrass (Agropyron smithii) historically dominated the Palouse prairie grassland.
Representative mammals found in the Palouse grasslands include the Yellow-bellied Marmot (Marmota flaviventris), found burrowing in grasslands or beneath rocky scree; American Black Bear (Ursus americanus); American Pika (Ochotona princeps); Coast Mole (Scapanus orarius), who consumes chiefly earthworms and insects; Golden-mantled Ground Squirrel (Spermophilus lateralis); Gray Wolf (Canis lupus); Great Basin Pocket Mouse (Perognathus parvus); Northern River Otter (Lontra canadensis); the Near Threatened Washington Ground Squirrel (Spermophilus washingtoni), a taxon who prefers habitat with dense grass cover and deep soils; and the Northern Flying Squirrel (Glaucomys sabrinus), a mammal that can be either arboreal or fossorial.
There are not a large number of amphibians in this ecoregion. The species present are the Great Basin Spadefoot Toad (Spea intermontana), a fossorial toad that sometimes filches the burrows of small mammals; Long-toed Salamander (Ambystoma macrodactylum); Northern Leopard Frog (Glaucomys sabrinus), typically found near permanent water bodies or marsh; Columbia Spotted Frog (Rana luteiventris), usually found near permanent lotic water; Pacific Treefrog (Pseudacris regilla), who deposits eggs on submerged plant stems or the bottom of water bodies; Tiger Salamander (Ambystoma tigrinum), fossorial species found in burrows or under rocks; Woodhouse's Toad (Anaxyrus woodhousii), found in arid grasslands with deep friable soils; Western Toad (Anaxyrus boreas), who uses woody debris or submerged vegetation to protect its egg-masses.
There are a limited number of reptiles found in the Palouse grasslands, namely only: the Northern Alligator Lizard (Elgaria coerulea), often found in screes, rock outcrops as well as riparian vicinity; the Painted Turtle (Chrysemys picta), who prefers lentic freshwater habitat with a thick mud layer; Yellow-bellied Racer (Chrysemys picta); Ringneck Snake (Diadophis punctatus), often found under loose stones in this ecoregion; Pygmy Short-horned Lizard (Phrynosoma douglasii), a fossorial taxon often found in bunchgrass habitats; Side-blotched Lizard (Uta stansburiana), frequently found in sandy washes with scattered rocks; Southern Alligator Lizard (Elgaria multicarinata), an essentially terrestrial species that prefers riparian areas and other moist habitats; Pacific Pond Turtle (Emys marmorata), a species that usually overwinters in upland habitat; Western Rattlesnake (Crotalus viridis), who, when inactive, may hide under rocks or in animal burrows; Night Snake (Hypsiglena torquata); Western Skink (Plestiodon skiltonianus), who prefers grasslands with rocky areas; Western Terrestrial Garter Snake (Thamnophis elegans), found in rocky grasslands, especially near water; Rubber Boa (Charina bottae).
- C. Michael Hogan & World Wildlife Fund. 2014."Palouse grasslands". Encyclopedia of Earth, National Council for Science and the Environment, Washington DC ed.Mark McGinley.
- D.W.Meinig. 1968. The Great Columbia Plains: A Historical Geography, 1805-1910. University of Seattle Press, Seattle (Revised 1995). ISBN 0-295-97485-0.
Yellow-bellied marmots generally live in moderately warm, dry habitats at low to mid elevations. They are found in many different habitats, including semi-desert, woodland and forest openings, and the alpine zone. Those that live further south live at higher elevations. For example, in the White Mountains of California they are found only above 2000 m. Moreover, because of absence from valleys, southern populations are isolated from one other, forming isolated populations. In addition, congeners may affect their distribution. It can be inferred that the presence of hoary marmots inhibit the distribution of yellow-bellied marmots in certain high elevation areas, as both occupy subalpine and alpine areas. Yellow-bellied marmots inhabit vegetated fortified slopes or rock outcrops in meadows, which serve as support for the burrows that they reside in, as well as sunning and observation posts. The main entrance of burrow, which they dig themselves, is usually about 0.6 m deep into the ground, and extends about 3.8 to 4.4 m horizontally into the hillside. Many short tunnels branch from main passageway, sometimes connecting to other burrows. Burrows stay relatively stable and thus serve as preferable places to raise young, hibernate, and hide from potential predators. Burrow availability may affect marmot distribution, as well as visibility and safety from predators. Most yellow-bellied marmots occur around 2000 m in elevation.
Average elevation: 2000 m.
Habitat Regions: terrestrial
Terrestrial Biomes: desert or dune ; savanna or grassland ; forest ; mountains
- Blumstein, D., A. Ozgu, V. Yovovich. 2006. Effect of predation risk on the presence and persistence of yellow-bellied marmot (Marmota flaviventris) colonies. Journal of Zoology, v. 270 no. 1: 132-138. Accessed February 23, 2011 at http://web.ebscohost.com/ehost/pdfviewer/pdfviewer?hid=113&sid=d0bb74af-5002-40cc-acc3-d8f2b6e902d3%40sessionmgr115&vid=3.
Habitat and Ecology
Mating typically occurs during two weeks following hibernation Gestation lasts about 30 days. Litters vary in size between 3-8 young per year. Young remain in burrow for 20-30 days (Frase and Hoffmann 1980), emerge from natal burrow late June to mid-July in the mountains of western Colorado. Local reproductive traits vary somewhat depending on the time of snow melt. At the highest elevations, females rarely produce litters in consecutive years (Armitage 1991). Males typically first breed at age three or older (Armitage 1991).
Lives alone, in pairs, or colonies. Colonies typically consist of one or more adult territorial males, 1-5 adult females and their young (usually including yearlings and younger offspring). Virtually all males and slightly less than half the females disperse from the natal colony, typically as yearlings and regardless of population density in males; dispersal distance usually is less than four km but up to 15.5 km for males and 6.4 km for females in western Colorado (Armitage 1991).
May harbour fleas that are vectors of sylvatic plague or tick that transmits Rocky Mountain spotted fever. These marmots are generalist herbivores, feeding on a wide variety of grasses and forbs. They do not store food for the winter.
At higher elevations it may hibernate early September-May; at lower elevations it may emerge late February to mid-March. In the mountains of western Colorado, spring emergence from hibernation begins in late April or early May, emergence for hibernation begins in late August and usually is completed by mid-September (Armitage 1991). In more boreal zones may be active all summer but may begin aestivation in June at lower elevations (Frase and Hoffmann 1980).
Comments: Yellow-bellied marmots occupy alpine tundra, subalpine and montane meadows, and foothills and canyons at lower elevations. They are semifossorial; individuals use one or more burrows; may share hibernation burrow. Burrows open under rocks (or logs or bushes) in areas of well-drained talus, rock outcrops, or scattered boulders. Habitat sizes range from 0.01 to 70 ha or more (Armitage 1991). 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.
Virtually all males and slightly less than half the females disperse from the natal colony, typically as yearlings and regardless of population density in males; dispersal distance usually is less than 4 km but up to 15.5 km for males and 6.4 km for females in western Colorado (Armitage 1991).
In Colorado, home range size of adult males varied greatly (0.06-47.5 ha, median 1 ha); several males made excursions from their home range (Salsbury and Armitage 1994).
Yellow-bellied marmots are herbivorous, eating a large range of plant types, including grasses, flowers, and forbs. In late summer, large numbers of seeds are eaten. They are most likely not food limited, eating only 0.8 to 3.1% of available net primary production. Food might be limited in areas where snow cover remains into the spring. They are selective feeders and are known to reject parts of plants that are toxic.
Plant Foods: seeds, grains, and nuts; flowers
Primary Diet: herbivore (Folivore , Granivore )
Comments: Generalist herbivore. Feeds on a wide variety of grasses and forbs. Does not store food for the winter.
Interspecific competition with other species, such as hoary marmots may affect the distribution and density of yellow-bellied marmots. As seed predators, yellow-bellied marmots may serve as habitat engineers that contribute to the density and composition of plant communities throughout their geographic range. In addition, yellow-bellied marmots are important prey for a number of different aerial and terrestrial predators. Once abandoned, burrows likely serve as important habitat for other fossorial and semi-fossorial species.
Ecosystem Impact: disperses seeds; creates habitat
- Nelson, B. 1980. Plague studies in California—the roles of various species of sylvatic rodents in plague ecology in California. Proceedings of the 9th Vertebrate Pest Conference: 89-96. Accessed February 23, 2011 at http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1029&context=vpc9.
Yellow-bellied marmots have a variety of aerial and terrestrial predators. Coyotes are their most important predator, followed by badgers, American martens, black bears, and golden eagles. Risk of predation may influence foraging behavior, social behavior, and habitat selection, as individuals attempt to reduce risk of predation by remaining in burrows for extended periods of time. Predation appears to be only a minor cause of mortality for colonial animals and is more significant among populations residing at habitat margins.
- coyotes (Canis latrans)
- badgers (Taxidea taxus)
- American martens (Martes americana)
- black bears (Ursus americanus)
- golden eagles (Aguila chrysaetos)
Anti-predator Adaptations: cryptic
- Armitage, K. 2004. Badger Predation on Yellow-bellied Marmots. The American Midland Naturalist, v. 151 no. 2: 378-387. Accessed February 23, 2011 at http://vnweb.hwwilsonweb.com/hww/results/external_link_maincontentframe.jhtml?_DARGS=/hww/results/results_common.jhtml.44.
- Van Vuren, D. 2001. Predation on Yellow-Bellied Marmots (Marmota Flaviventris). American Midland Naturalist, Vol. 145, No. 1: 94-100. Accessed February 23, 2011 at http://www.jstor.org/stable/3083083?seq=3&Search=yes&searchText=marmots&searchText=risk&searchText=predation&searchText=yellow-bellied&searchText=Foraging&list=hide&searchUri=%2Faction%2FdoBasicSearch%3FQuery%3DForaging%2Band%2Bpredation%2Brisk%2Bin%2Byellow-bellied%2Bmarmots%26acc%3Don%26wc%3Don&prevSearch=&item=1&ttl=40&returnArticleService=showFullText&resultsServiceName=null.
Yellow-bellied marmot communication includes auditory and chemical signals. They express alarm, alertness, or threats through whistles. They use their cheek glands to leave scent marks that may help convey social status.
These marmots live alone, in pairs, or colonies. Colonies typically consist of one or more adult territorial males, 1-5 adult females and their young (usually including yearlings and younger offspring). Small habitat patches may include a female and her offspring but adult males and yearlings may not be present (Armitage 1991).
May harbor fleas that are vectors of sylvatic plague or tick that transmits Rocky Mountain spotted fever.
Life History and Behavior
Communication between yellow-bellied marmots is mostly auditory and visual. There are three main vocalizations: the whistle, the undulating scream, and the tooth chatter. Six different whistles are recognized and may have more than one function, such as alerting and threatening. Screams usually respond to excitement or fear, and tooth chattering is used as a threat. Other animals such as American pikas and golden-mantled ground squirrels may respond to marmot alarm calls. Yellow-bellied marmots have cheek and anal glands. Scent marking occurs with cheek glands in conflict situations, having more of a dominance rather than territoriality function.
Communication Channels: visual ; acoustic ; chemical
Other Communication Modes: scent marks
Perception Channels: visual ; tactile ; acoustic ; chemical
Comments: At higher elevations these marmots hibernate from early September to May; at lower elevations they may emerge as early as February to mid-March. In the mountains of western Colorado, spring emergence from hibernation begins in late April or early May; immergance for hibernation begins in late August and usually is completed by mid-September (Armitage 1991). In some lower elevation areas, marmots may estivate during dry periods in summer. In more boreal zones, marmots may be active all summer but may begin estivation in June at lower elevations (Frase and Hoffmann 1980).
Activity occurs in daylight. Activity is unimodal with peak activity in early afternoon in spring and fall, bimodal with peaks in morning and late afternoon in summer (Armitage 1991).
Most yellow-bellied marmots live for 13 to 15 years in the wild. Predation, which accounts for 98% of summer mortality significantly limits the average lifespan of this species. A significant number of deaths occur during hibernation and emigration. Recently, sylvatic plague, caused by the bacterium Yersinia pestis, has had a significant impact on populations in California.
Status: wild: 13 to 15 years.
Lifespan, longevity, and ageing
Yellow-bellied marmots are most often classified as polygynous. They can live as members of a colony, or as single or paired animals. About 75% of individuals live in colonies, 16% in “satellite sites”, and 7% in temporary sites. Satellite sites are secondary habitats consisting of only a few burrows. Those in colonies are members of harems, groups consisting of adult males, and females and their offspring. All males and about 40% of females are recruited from outside the colony. Reproductive rates at “satellite sites” are lower than in colonies and have more size fluctuation and shorter residencies than colonies and temporary/transient sites.
Mating System: polygynous ; cooperative breeder
Yellow-bellied marmots reach reproductive maturity by two years of age. Hence, no female yearlings produce offspring. Only 25% of two-year old females produce a litter. The testes of adult males are enlarged for several weeks when they awake from winter hibernation and then eventually regress to become the same size as juveniles. There is one breeding season per year, which starts and is concentrated in the first two weeks after they awake from winter hibernation. Gestation lasts for approximately 30 days, and litter sizes range from 3 to 8 pups, with an average of 4.32 pups. Adult females have an average corpus luteum count of 4.7. Newborn pups are 111 mm in length and weigh 33.8 g on average.
Breeding interval: Yellow-bellied breed once yearly.
Breeding season: Most populations of yellow-bellied marmots breed during May and June.
Range number of offspring: 3 to 8.
Average number of offspring: 4.32.
Average gestation period: 30 days.
Average weaning age: 7 weeks.
Average time to independence: 7 weeks.
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); sexual ; viviparous
Average birth mass: 33.8 g.
Average gestation period: 30 days.
Average number of offspring: 4.
Average age at sexual or reproductive maturity (male)
Sex: male: 730 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 730 days.
There is little information available regarding parental care in yellow-bellied marmots. Mothers nurse pups for about 3 weeks, at which time pups emerge from the burrow. Parental care decreases substantially once pups emerge; however, strong social bonds remain for an extended period, especially in colonial populations.
Parental Investment: altricial ; female parental care ; pre-weaning/fledging (Provisioning: Female); post-independence association with parents
- Blumstein, D., S. Im, A. Nicodemus. 2004. Yellow-bellied Marmots (Marmota flaviventris) Hibernate Socially. Journal of Mammalogy, v. 85 no. 1: 25-29. Accessed February 23, 2011 at http://web.ebscohost.com/ehost/pdfviewer/pdfviewer?hid=113&sid=dab8744a-8939-4ad8-ad04-24a32b9c2f9e%40sessionmgr111&vid=3.
- Frase, B., R. Hoffmann. 1980. Marmota flaviventris. Mammalian Species, No. 135: 1-8. Accessed February 23, 2011 at http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-135-01-0001.pdf.
- Wey, T., D. Blumstein. 2010. Social cohesion in yellow-bellied marmots is established through age and kin structuring. Animal Behaviour, Volume 79, Issue 6: 1343-1352. Accessed February 23, 2011 at http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4YT6NFR-4&_user=1086025&_coverDate=06%2F30%2F2010&_alid=1653968587&_rdoc=1&_fmt=high&_orig=search&_origin=search&_zone=rslt_list_item&_cdi=6693&_sort=r&_st=13&_docanchor=&view=c&_ct=2&_acct=C000051441&_version=1&_urlVersion=0&_userid=1086025&md5=73a3138382c8b5605940f8c589f96915&searchtype=a.
Mating typically occurs shortly after emergence from hibernation. Gestation lasts about 30 days. Litters vary in size between 3-8 young/year. Young remain in burrow for 20-30 days (Frase and Hoffmann 1980), emerge from the natal burrow in late June or July in the mountains of western Colorado, but range-wide reproductive timing varies with elevation and the timing of snow melt. At the highest elevations, females rarely produce litters in consecutive years (Armitage 1991). Males typically first breed at age three or older (Armitage 1991).
Yellow-bellied marmots are classified as a species of "least concern" on the IUCN's Red List of Threatened Species. Currently, there are no major threats to the long-term persistence of this species.
IUCN Red List of Threatened Species: least concern
IUCN Red List Assessment
Red List Category
Red List Criteria
- 1996Lower Risk/least concern(Baillie and Groombridge 1996)
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Relevance to Humans and Ecosystems
Yellow-bellied marmots are known carriers of the plague, caused by the bacterium Y. pestis. Although uncommon, humans that come into direct physical contact with this species may be at risk of contracting the plague.
Negative Impacts: injures humans (causes disease in humans )
In certain regions of its geographic range, yellow-bellied marmots killed for sport, food, or fur.
Positive Impacts: food ; body parts are source of valuable material
Yellow-bellied marmots usually weigh from 1.6 to 5.2 kilograms (3.5 to 11.5 lb) when fully grown, though males typically weigh more than females. Adult males typically weigh between 3 to 5 kilograms (6.6 to 11.0 lb); females typically weigh between 1.6 to 4 kilograms (3.5 to 8.8 lb). They have a brown coat, a white patch of fur between the eyes, a reddish-brown tail, and a yellow belly, from which they get their name. Their ears are small and round, and they have a short white muzzle with a black nose. They get fatter in the autumn just before hibernating.
Habitat and distribution
The yellow-bellied marmot lives in the western United States and southwestern Canada, including the Rocky Mountains and the Sierra Nevada. It inhabits steppes, meadows, talus fields and other open habitats, sometimes on the edge of deciduous or coniferous forests, and typically above 6,500 feet (2,000 m) of elevation.
Their territory is about 4 to 7 acres (2 to 3 ha) around a number of summer burrows. Marmots choose to dig burrows under rocks because predators are less likely to see their burrow. Predators include wolves, foxes, coyotes, dogs and eagles. When a marmot sees a predator, it whistles to warn all other marmots in the area (giving it the nickname "whistle pig"). Then it typically hides in a nearby rock pile.
Behavior and diet
Marmots reproduce when about two years old, and may live up to an age of fifteen years. They reside in colonies of about ten to twenty individuals. Each male marmot digs a burrow soon after he wakes up from hibernation. He then starts looking for females, and by summer may have up to four female mates living with him. Litters usually average three to five offspring per female. Only about half of those pups survive and become yearlings. Marmots have a "harem-polygynous" mating system in which the male defends two or three mates at the same time. Female offspring tend to stay in the area around their home. Male offspring typically leave when they are yearlings and will defend one or more females.
Yellow-bellied marmots spend about 80% of their life in their burrow, 60% of which is spent hibernating. They often spend mid-day and night in a burrow as well. These burrows are usually constructed on a slope, such as a hill, mountain, or cliff. The hibernation burrows are can be up to 5 to 7 metres (16 to 23 ft) deep, but the burrows constructed for daily use are usually only 1 metre (3.3 ft) deep. Their hibernation period varies on elevation, but it is typically from September to May. Occasionally, they will climb trees and other flora, but they are usually terrestrial.
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