Like all marmots, the Vancouver Island marmot lives in one or more families. Families typically contain one adult male, up to two adult females, sub-adults, juveniles and the offspring produced that year (2). The colony lives in a complex series of underground burrows, and communicates by direct contact and whistling vocalisations including a high-pitched alarm whistle to warn others of impending danger (2). Hibernation occurs each winter between the end of September and early May, and hibernacula are characterised by the presence of grass and mud plugs sealing the burrow entrance during autumn, and tunnels in the snow after the occupants have emerged (2). During hibernation, marmots live off stored fat reserves built up in summer (4). Sexual maturity is reached at about four years of age, after which individuals breed every other year. Mating occurs in the burrow during the months of spring, and the litter, which usually contains three pups, is produced towards the beginning of July (2). The diet consists of over 50 species of grass and flowering plants (2).