The moose (North America) or elk (Eurasia), Alces alces is a member of the New World deer subfamily and is the largest and heaviest extant species in the Deer family. Moose are distinguished by the broad, palmate (open-hand shaped) antlers of the males; other members of the deer family have antlers with a dendritic ("twig-like") configuration. Moose typically inhabit boreal forests and temperate broadleaf and mixed forests of the Northern Hemisphere in temperate to subarctic climates. Hunting and other human activities have caused a reduction in the size of the moose's range over time. Moose have been reintroduced to some of their former habitats. Currently, most moose are found in Canada, Alaska, New England (with Maine having the most of the lower 48 states), Fennoscandia, Baltic states, and Russia. Their diet consists of both terrestrial and aquatic vegetation. The most common moose predators are the gray wolf along with bears and humans. Unlike most other deer species, moose do not form herds and are solitary animals, aside from calves who remain with their mother until the cow begins estrus (typically at 18 months after birth of the calf), at which point the cow chases away young bulls. Although generally slow-moving and sedentary, moose can become aggressive and move quickly if angered or startled. Their mating season in the autumn features energetic fights between males competing for a female.