The breeding season or rut begins in mid to late September and runs through October. Bulls begin breeding activities by setting up territories and attract cows by calling with a low grunting sound that resonates across the willow bottoms. Both bulls and cows are aggressive during the breeding season. Bulls often fighting head to head until the dominate bull drives off or injures or even kills the challenger. Cows give birth in May and June.
Twins are common in good habitat, and triplets have been documented.
Live up to 20 years in the wild. Moose have long legs, which allow them to traverse deep winter snows and thick willow habitat types. In spite of their size, they often go unnoticed as they spend a great deal of time in heavy, dark cover in willow bottoms and forests. Moose can be found in sagebrush, high in the mountains above timberline, as well in the more traditional willow, aspen, pine and beaver pond type habitats. However, moose prefer riparian habitats with willows, which is their primary food source.