Moose thrive in wetlands rich with willow, marsh grasses, and aquatic plants. Solitary by nature, some remain in this habitat year-round, while others migrate seasonally into mountain canyons to feed on summer vegetation and return to the valley as winter approaches. This habitat also supports other animals that benefit directly from moose living here. A bull moose's antlers reach full size in late summer, then are shed in early winter after the autumn rut, and rodents and other animals gnaw the fallen antlers as a valuable source of calcium critical to their survival. The largest member of the deer family, moose may weigh more than 1,000 pounds and stand seven feet tall. Though they may appear docile, moose are unpredictable and powerful, and rutting bulls may charge people while cows fiercely protect their calves.