Yellow-bellied Marmot (Marmota flaviventris)

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.

Distribution

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)

Morphology

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.

Life cycle

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.

Conservation

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.