Yellow-bellied Marmot
Marmota flaviventris

f4.8 @ 1/5000s, ISO:1000, Nikon D3S w 500mm

"Yellow-bellied Marmot," Wikipedia, the free encyclopedia. The yellow-bellied marmot, 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. Only about half of those pups survive and become yearlings. Marmots have a "harem-polygynous" mating system in which the male reproduces with two or three mates at the same time. Female offspring tend to stay in the area around their home. Male offspring typically leave when they are yearlings and will defend one or more females.
Mt. Evans (14,271 ft.), Rocky Mountains, Colorado