August 1, 2009; Mt. Washburn;Yellowstone National Park.

From Wikipedia:
The yellow-bellied marmot (Marmota flaviventris), also known as the rock chuck, is a ground squirrel in the marmot genus.

Marmots reproduce when about two years old, and may live up to an age of fifteen years. They reside in colonies of about ten to twenty individuals. Each male marmot digs a burrow soon after he wakes up from hibernation. He then starts looking for females, and by summer may have up to four female mates living with him. Litters usually average three to five offspring per female.[2] Marmots have a "harem-polygynous" mating system in which the male defends two or three mates at the same time.[2]
Yellow-bellied marmots are diurnal.[2] The marmot is also an omnivore, eating grass, leaves, flowers, fruit, grasshoppers, and bird eggs.