The rock outcrops on the northwest corner of Ash Creek Wildlife Area (Modoc County CA) are perfect habitat for yellow bellied marmots (Marmota flaviventris). These large rodents, belonging to the ground squirrel family, inhabit rock slides, talus slopes, lava beds and meadows with rock outcrops in the Rocky Mountains, Cascades and Sierras of the West.
Also known as rockchucks, yellow bellied marmots are a grizzled yellow-brown above with white-tipped hairs. The face is black with white between the eyes. The undersides are yellow. Yellow bellied marmot tracks show four toes on the front feet and five toes on the back.
In April or May marmots emerge from their dens, thin after hibernating throughout the winter. They immediately begin to eat vegetation (mostly grasses, leaves and flowers), putting on heavy layers of fat over the summer. Grasshoppers and bird eggs also contribute to their diet. Covered with fat, the marmots return to their dens in September or October to once again begin their winter hibernation. A yellow bellied marmot once spent summer afternoons sunning on the picnic table outside my kitchen window. By fall it had so much stored fat that it “jiggled” when walking. All I could think of when looking at this round ball was a wiggly bowl of Jello.
Yellow bellied marmots spend their days alternating between foraging and resting or sunning on rocks, preferring rocks with a wide view. This “lookout” is covered with their blackish droppings. When sensing danger marmots give a sharp shrill whistle and scurry to their burrows, built under rock piles or in tangles of tree roots. Here carnivores, their main enemies, cannot get to them.
Males will usually mate with and defend two or three females. They live in small colonies. Three to eight young are born in the spring and by July are ready to leave the den. Sons will go off to start their own harems, females often remain in close proximity to their mother.
These marmots, who live practically across the road from our house, are rather sleek following their winter “sleep”. By fall they will be much more rotund.