Marmota flaviventris
yellow-bellied marmot

Yellow-bellied marmots range from southwestern Canada throughout the western United States.

Yellow-bellied marmots generally occupy open habitats such as steppes, alpine meadows, pastures, gravel-covered fields and forest edge. These marmots prefer to construct their burrows on open, grassy or herb-covered slopes. They generally occupy elevations of about 2,000 m but can be found at elevations up to 4,100 m in the Rocky Mountains.

Male marmots are heavier than females, ranging from 2.95 to 5.22 kg, while females range in weight from 1.59 to 3.97 kg. Total body length ranges from 490 to 700 mm in males and 470 to 670 mm in females. Tail length ranges from 126 to 220 mm. Yellow-bellied marmots have distinct yellow speckles on the sides of their necks, white between their eyes, yellow to red-yellow bellies and yellow-brown to tan, straight hair with white tips. They also have a thumb stump with a nail. Melanism is widely found south of the Rocky Mountains.

Marmota flaviventris individuals spend most of their lives in a burrow with several entrances, which they excavate in well-drained soil. The burrows are usually over 1 m in depth, but hibernation burrows may be 5-7 meters deep. Tunnels may be 10-70 m in length. Yellow-bellied marmots are mainly diurnal and terrestrial, but they occasionally climb into shrubs and trees. They hibernate from September-May each year, though hibernation length varies with elevation.

The basic social unit in Marmota flaviventris consists of a single adult male with a harem of 2-3 adult females. A colony of marmots in a given area may contain one or more such harems. Adult males are territorial and agonistic toward one another, but young males are allowed to remain with the parents until the second summer of life and are then driven out by the adults. Females in a harem behave amicably toward each other and often raise their offspring jointly. About 90% of a population lives in social groups, occupying territories of approximately 1.6 acres, while the rest are solitary without permament abode.

Ataple foods of yellow-bellied marmots include the leaves and blossoms of a great variety of herbaceous plants and grasses. They also consume fruit, grains, legumes, and occasionally insects. They largely forage for seed in the late summer.

In rare instances when it lives near human agricultural/farming operations, the yellow-bellied marmot can be a pest because of its raids on crops and the hazards posed by its burrows to farm machinery and livestock.

In some areas, marmots are important game animals and are killed regularly for sport, food, or fur.

Yellow-bellied marmots are fairly common throughout their range and have no special conservation status, though isolated populations on mountains in the southern part of their range and in the Black Hills of South Dakota are at risk.

Marmota flaviventris has 11 subspecies that populate different areas of western North America.