Yellow-Bellied Marmot (Marmota flaviventris) lives in alpine meadows across Western North America. It feeds on grass and leaves. Its conservation status is Least Concern.
Fascinating facts about the Yellow-Bellied Marmot
- Yellow-bellied marmots spend most of their lives underground: about 80% of their time is in burrows and 60% of that is hibernation. Their hibernation stretches from September to May, roughly eight months without storing food, so they must bulk up in autumn to survive the long fast. This extreme reliance on seasonal fat reserves shows how hibernation shapes their physiology and makes them especially vulnerable to any shift in winter length.
- An adult yellow-bellied marmot can weigh anywhere from 1.6 kg to 5.2 kg, with males usually heavier than females. Their body mass swings dramatically through the year, hitting its low in early spring after hibernation and peaking in early autumn after months of foraging. This seasonal weight swing underlines how critical summer feeding is for building the fat stores needed for their eight-month winter sleep.
- These marmots are true colony animals, forming groups of up to twenty individuals that share a network of burrows across about 2.5 hectares (6 acres). When a predator appears, one individual lets out a high-pitched whistle that alerts the whole group, prompting them to hide in nearby rock piles. Such coordinated alarm calls illustrate vocal communication for a social, ground-dwelling rodent.
- Mating is a brief, two-week frenzy that begins right after the marmots emerge from hibernation. Females give birth after a 30-day gestation to litters of three to eight pups, averaging about 4.3 offspring. Only about half of the newborns survive to become yearlings, and the young stay with the colony until they disperse at one year of age. This tight breeding window and modest survival rate highlight the importance of a successful summer for population maintenance.
- Climate warming is already reshaping marmot life cycles: milder springs end hibernation earlier and push the breeding season forward, lengthening the growing season. This extra time lets marmots pack on more fat, raising average body mass and driving population growth.
Sources
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At a glance
RangeWestern North America
HabitatAlpine meadows
DietGrass and leaves
About the Yellow-Bellied Marmot
In the sun-drenched meadows of the Rocky Mountains, the yellow-bellied marmot reigns as a charismatic monarch, its bright fur glistening like golden armor as it surveys its kingdom from a rocky outcropping. With a languid ease, it moves through its domain, its stout body undulating as it navigates the grassy expanse, ever vigilant for the telltale sign of a predator. As it sounds its distinctive whistle, a piercing call that echoes across the landscape, the marmot's remarkable adaptability and resilience are revealed, a testament to its enduring presence in this breathtaking alpine world.
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