Yellow-bellied Marmot

Yellow-bellied marmots usually weigh from 1.6–5.2 kg (3 lb 8 oz – 11 lb 7 oz) when fully grown, though males typically weigh more than females. The weight fluctuates quite drastically through the year, with the least measured in early spring and the most measured in early autumn. Adult males typically weigh between 3–5 kg (7–11 lb) and adult females typically weigh between 1.6–4 kg (3+1⁄2–9 lb). They measure from 47–68 cm (18+1⁄2–27 in) in length, have a short tail measuring 13–21 cm (5–8+1⁄2 in) with buffy, reddish and black hairs and hindfoot measuring 7–9 cm (3–3+1⁄2 in). They have a rather frosty appearance with some of the guard hairs having pale tips with dark bands. The yellow-bellied marmot has a broad and flat skull, dark head, and a dark nose with a white furry patch. The pelage comprises coarse, long outer hairs and woolly, shorter underfurs. They have a brown coat, a white patch of fur on the snout in front of the eyes. Due to the bright yellow fur on their belly, sides of the neck, and throat, they get their scientific and common names. Their ears are small and round, measuring 1.8–2.2 cm (11⁄16–7⁄8 in) in length, having a short white muzzle. Their back is reddish-brown in color with grizzled black and light-grey tan. Their feet are yellowish to dark brown to in color. …

The yellow-bellied marmot lives in southwestern Canada and western United States, including the Rocky Mountains and the Sierra Nevada. Northwards, its range extends into the southern British Columbia and goes eastwards up to the montane and basin regions of Wyoming, eastern Montana, Colorado, and southern Alberta. Southwards, its range extends into northern New Mexico. It inhabits steppes, meadows, talus fields, and other open habitats, sometimes on the edge of deciduous or coniferous forests. In Colorado, they are found from as low as 1,600 m (5,400 ft) to over 4,300 m (14,000 ft) of elevation. In central and eastern Washington, they are common at low elevations. While not native to the area, they have been found in the San Francisco Bay Area. Naturalists report they travel down out of the Sierra in the engine compartments of vehicles as they are notorious for seeking sweet-smelling radiator fluid. They are found in valleys, meadows, and foothills, and tend to occupy open areas which are free of vegetation. Their territory is about 2.5 hectares (6 acres) around a number of burrows dug during the summer. Although they sometimes burrow underneath trees and buildings, they typically choose to dig burrows under rocks, as it is less likely to be visible to predators. These predators include foxes, dogs, coyotes, wolves, and eagles. …

Marmots have a single, 2-week long breeding season annually. Marmots reproduce starting at around two years of age, and may live up to an age of fifteen. They can live alone, in pairs, or in colonies of about ten to twenty individuals. Each male marmot digs a burrow soon after it wakes from hibernation, and starts looking for females to reproduce. By summer, it may have up to four female mates. 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 reproduces with two or three females at the same time. Colonies are composed of one or more of these harems. Although typical only the females tend to be monogamous, males can be monogamous in an environment with fewer females. Female offspring tend to stay in the area around their home, while male offspring typically leave when they are yearlings and will defend one or more females.