Yellow-bellied marmots usually weigh between 5 and 11 pounds (2 and 5 kg) when fully grown. They get fatter in the fall 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, and coyotes. 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.
Female with nursing pup, Kamloops, British Columbia
Behavior and diet
Marmots reproduce when about two years old, and may live up to an age of 15 years. They reside in colonies; a colony is a group of about ten to 20. Each male marmot digs a burrow soon after he wakes up from hibernation. He then starts looking for females, and by summer has up to four females living with him. Litters usually average 4-5 offspring per female. Marmots have what is called "harem-polygynous" mating system, which means the male defends up to four mates at the same time.
Yellow-bellied marmots are diurnal. The marmot is also an omnivore, eating grass, leaves, flowers, fruit, grasshoppers, and bird eggs.
Marmots eating trash left by backpackers at Trail Camp near Mount Whitney, CA