The Yellow-bellied Marmot is a small, diurnal species of marmot (ground squirrel) that usually weighs between 5 and 11 pounds (2 and 5 kg) when fully grown. It is brown on the back and tan to yellow on the front. The head is black, with a light-coloured white or tan area in front of the eyes. It has a slightly bushy tail similar to other marmots.
Yellow-bellied Marmots construct three types of burrows—a home, an escape from predators, and a hibernaculum (Nagorsen 2005). They generally require suitable soil for digging, a steep slope, and rocks or tree roots at the entrance to the burrow for support (Nagorsen 2005).
The Yellow-bellied Marmot is found in the western Cordillera from southern British Columbia and Alberta south to California (Nagorsen 2005). In British Columbia, the Yellow-bellied Marmot is found in the south-central part of the province, in the Fraser and Thompson plateaus, and the southern mountains, including the Cascades, Monashees and Selkirks (Nagorsen 2005). In this region, it is generally found east of the Fraser River, north to Williams Lake—there is one historical specimen from Prince George (Nagorsen 2005).
Occasional sightings of this species are reported in the lower Fraser Valley and elsewhere outside of the main range. One population was reported established in North Vancouver (Nagorsen 2005), and there are periodic reports of sightings in Richmond, Vancouver and other municipalities (photo documentation, various sources). Additionally, there are several recent observations on SE Vancouver Island and a recent observation on Quadra Island (Nagorsen 2010 pers. Comm.).