Moose - biology.

Moose - biology. Moose, common name for the largest member of the deer family. The name moose, given by the Algonquin, a native North American tribe, means "eater of twigs," reflecting the animal's primary diet of leaves and twigs. Moose are referred to as elk in Europe and Asia, where they inhabit the forests of northern Asia and Europe from Siberia in the east to Norway in the west, the Baltic region, and northern China. In North America moose are found in wooded areas of Canada and the northern United States. The deer known in North America as elk is also called wapiti. Moose are huge animals, with males, known as bulls, standing up to 2 m (6.5 ft) at the shoulder. Some bulls weigh more than 726 kg (1600 lb). Their characteristically long legs enable them to both browse on low bushes and small trees and wade in lakes and ponds to feed on aquatic plants. Once in the water, moose move easily and are powerful swimmers. The head of the moose is large with an overhanging upper lip, or muzzle. A drooping growth of hair and skin, called a bell, hangs from the throat. The large, constantly moving ears of the moose act like radar, providing excellent hearing. A large shoulder hump is formed by the upward projections from neck vertebrae. Strong ligaments, which are necessary to hold the large head erect, are attached to these upward projections. The body color of the moose is generally brownish-black, with the face lightening to a brown color in the summer. The face of bulls darkens to a dark brown or black color as the breeding season approaches. Prominent features of bulls are the enormous antlers with marginal prongs, or tines, which can exceed 1.5 m (60 in) in width and 22.7 kg (50 lb) in weight. Antlers are covered with a soft, nutrient-rich skin called velvet, which is shed in early September and often eaten by bulls. Antlers themselves are shed each year after the mating season, which generally is in late September. Older bulls shed their antlers in December, and by the end of January most bulls have shed their antlers. Occasionally, some young ones will carry antlers into February. New antlers begin to grow in early April. Moose generally are solitary animals, although they may band in small groups of up to a dozen or more during the breeding season, especially in Canada's Yukon territory and Alaska. Both females and males are capable of mating in their second year of life. During mating, bulls battle for the female moose, or cows, engaging in antler fights with other males. After mating, gestation is around 230 days, with most calves born near the end of May. Cows usually bear one offspring, although twins are common and births of three or four calves have also been observed. Calves have reddish-brown coats and weigh 11 to 16 kg (24 to 35 lb) at birth. The average life span of moose is about 5 to 6 years, although some moose can live as long as 20 years. The age of a moose is determined by examining the root portion of the middle incisor teeth, which show a pattern of rings. Just as a tree's growth rings reveal its age, the dark ring in a moose's middle incisor combined with a light ring accounts for each year of age. Moose feeding habits vary with the seasons. During the fall, winter, and spring, they feed on the previous summer's growth of aspen, black poplar, willow, birch, hazel, dogwood, and balsam fir. In late spring and early summer, moose lick natural salt deposits, found in salt springs or roadside runoff to replenish their mineral reserves used up over winter. In summer, moose prefer vegetation that grows in water, and they can submerge for up to 40 seconds to reach plants beneath the water's surface. Despite their size and ability to attain running speeds of up to 58 km/h (36 mph) for short distances, moose fall prey to wolves and black and grizzly bears. Some studies have shown that bears can kill up to 75 percent of newborns in their first eight weeks of life. Another threat to moose is the winter tick. Tick infestations irritate the moose's skin, causing the moose to rub off portions of the hair they depend on for protection from the extreme winter cold, which typifies much of their habitat. Severe winters combined with heavy tick infestations can reduce moose populations as much as 50 percent. Scientific classification: The moose is a member of the deer family, Cervidae, and is classified as Alces alces. Contributed By: Vince Crichton Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.