Yellow-Bellied Marmots are easy to photograph early in the day, as they love the warmth of the morning sun before they start their daily search for food. They make whistle noises and chucking sounds. Whistle pig is this animal's nickname. The whistle means a predator is coming.

As Marmots hibernate in the winter, these slim springtime versions will double or triple their weight before winter to a total of 8 to 15 pounds. Marmots are hosts for the tick that carries Rocky Mountain spotted fever. They eat flowers, berries, and leaves, and occasionally insects and the eggs of ground nesting birds, so they are not strictly vegetarian.
This fellow was photographed at Pike’s Peak in Colorado.