Hoary Marmot - Behaviour and Diet

Behaviour and Diet

Hoary marmots are diurnal and herbivorous, subsisting on leaves, flowers, grasses, and sedges. Predators include golden eagles, grizzly and black bears, wolves, coyotes, red foxes, lynxes, cougars and wolverines. They live in colonies of up to 36 individuals, with a home range averaging about 14 hectares (35 acres). Each colony includes a single, dominant, adult male, up to three adult females, sometimes with a subordinate adult male, and a number of young and subadults up to two years of age.

The marmots hibernate seven to eight months a year in burrows they excavate in the soil, often among or under boulders. Each colony typically maintain a single hibernaculum and a number of smaller burrows, used for sleeping and refuge from predators. The refuge burrows are the simplest and most numerous type, consisting of a single bolt hole 1 to 2 metres (3 ft 3 in to 6 ft 7 in) deep. Each colony digs an average of five such burrows a year, and a mature colony may have over a hundred. Sleeping burrows and hibernacula are larger and more complex, with multiple entrances, deep chambers lined with plant material, and stretching to a depth of about 3.5 metres (11 ft). A colony may have up to 9 regular sleeping burrows, in addition to the larger hibernaculum.

Many forms of social behaviour have been observed among hoary marmots, including play fighting, wrestling, social grooming, and nose-to-nose touching. Such activity becomes particularly frequent as hibernation approaches. Interactions with individuals from other colonies are less common, and usually hostile, with females chasing away intruders. Hoary marmots are also vocal animals, with at least seven distinct types of calls, including chirps, whistles, growls, and whining sounds. Many of these calls are used as alarms, alerting other animals to potential predators. They also communicate using scent, both by defecation, and by marking rocks or plants using scent glands on their cheeks.

Hoary marmots frequently sun themselves on rocks, spending as much as 44% of their time in the morning doing so, although they will shelter in their burrows or otherwise seek shade in especially warm weather. They forage for the rest of the day, returning to their burrows to sleep during the night.

In areas frequented by people, hoary marmots are not shy. Rather than running away at first sight, they will often go about their business while being watched.

Mating occurs after hibernation, and two to four young are born in the spring. Males establish "harems", but may also visit females in other territories.