We found them at many places in the Rocky Mountains but always in higher elevations in the alpine tundra zone above 10,500 feet (~3200m). In some areas they are used to people and they may show up right beside the trail. In most instances they disappear between the rocks if you get too close. It needs a little patience and luck to catch them in a nice pose and good light. Quite often they sun bath on a rock or watch out for predators. The Yellow-bellied Marmots feed on green vegetation exclusively and in the fall they put on a layer of fat, which sustains them through hibernation during the winter.
Most of my images of the marmot were made while waiting patiently for another critter, that is much more difficult to get in front of the lens. I will report about this one shortly, so please stay tuned....