Yellow-bellied Marmot

After hiberating for up to eight months, yellow-bellied marmots emerge between February and May.

NPS/Neal Herbert

 

Yellow-bellied marmot track

Scientific Name

Marmota flaviventris

Identification

• 20–28 inches long; 3.5–11 pounds.
• One of the largest rodents in Yellowstone.
• Reddish-brown upper body; yellowish belly; small ears; prominent active tail.

Habitat

• Found from lowest valleys to alpine tundra, usually in open grassy communities and almost always near rocks.
• Feed on grasses and forbs in early summer; switch to seeds in late summer, occasionally will eat insects.
• Prey for coyotes, grizzlies, and golden eagles.

Behavior

• Hibernate up to 8 months, emerging from February to May depending on elevation; may estivate in June in response to dry conditions and lack of green vegetation and reappear in late summer.
• Breed within two weeks of emerging from hibernation; average five young per year.
• Active in morning, late afternoon, and evening.
• Colonies consist of one male, several females, plus young of the year.
• Vocalizations include a loud whistle (early settlers called them “whistle pigs”), a “scream” used for fear and excitement; a quiet tooth chatter that may be a threat.
• Males are territorial; dominance and aggressiveness demonstrated by waving tail slowly back and forth.