marmots. In fights that have been observed during a study, only about 10% of fights had distinct outcomes. When communicating vocally, they have four different types of whistles, differing in this from their close relatives, the hoary marmot and the Vancouver Island marmot. The Olympic marmot's whistles include flat calls, ascending calls, descending calls, and trills; all of these are in a small frequency range of about 2,700 Hz. Flat, ascending, and descending calls are most often voiced singly. The ascending call has a duration of about half a second, starting with a "yell" on one note and ending with a "chip" on a higher note; it is often used as a distress or warning call for unfamiliar smells and noises. These same "yips" are heard when Olympic marmots are play fighting, along with low growls and chattering of teeth. The descending call ends on a lower note than the one on which it started. The trill, which sounds like multiple ascending calls put together as one longer sound, consists of multiple ranging notes and is voiced as an alarm call to communicate to other marmots in the area that danger may be approaching and they should return to their burrows. Females with young have the responsibility to watch out for their young and other relatives near the burrow, and therefore voice the trill more often than other Olympic marmots. If marmots are not accustomed to human contact in a certain area, they may also sound a trill when seeing a person, in order to alert other marmots. At places like Hurricane Ridge, where seeing humans is a frequent occurrence, most marmots will not acknowledge human presence at all. They also communicate through the sense of smell. A gland located in their cheek exudes chemicals which they rub on scenting points, such as shrubs and rocks, which can be smelled by other marmots in the area. Hibernation Olympic marmots start to enter hibernation in early September. Before hibernating, the marmots bring dry grasses into the burrow for bedding or food. Sometimes in early September marmots will stay in their burrows for a few consecutive days, with only brief outings that allow for a little foraging. During this period, they do not play fight or socialize with other marmots; they limit themselves to peeking out and casually sitting outside their burrows. Nonparous females (those who have not given birth yet) and