Last week I spent a couple of nights camping at Great Basin National Park in east-central Nevada. One point of interest was a stretch of road near Baker Creek that was crawling with yellow-bellied marmots (Rodentia: Sciuridae: Marmota flaviventris). So many of these small mammals were scurrying across the road here that I had to drive very slowly to avoid squashing any.
A western relative of the eastern woodchuck (M. monax), these marmots are sometimes called “rockchucks.” Living mostly among rocky slopes they dig burrows in coarse gravel and sand. They hibernate underground from autumn through the winter, and once spring arrives they begin their activities in earnest.
In April and May one of their primary activities is breeding. Males tend to form harems and typically guard three or four females and their offspring. Females gestate for only about 30 days so new marmot pups are a common sight in May and June.
Once reproduction is out of the way these animals focus the rest of the summer season mostly on eating. They feed on the stems, leaves, flowers, and seeds of a wide variety of plants. They are not picky eaters, and this generalist herbivory has allowed them to flourish throughout the North American west.