The Alaskan moose, Alces alces gigas, is the largest moose subspecies and one of North America’s largest land mammals. These animals are characterized by their immense size and distinctive antlers. Their imposing stature results from adaptations to their northern environment, allowing them to thrive in the vast landscapes of Alaska and parts of the Yukon.
Key Measurements of Alaskan Moose
Adult Alaskan moose are notably large, especially males, known as bulls. A bull can stand over 2.1 meters (6.9 feet) at the shoulder and often weighs more than 635 kilograms (1,400 pounds). The largest recorded Alaskan moose, a bull shot in western Yukon in 1897, weighed 820 kilograms (1,808 pounds) and measured 2.33 meters (7.6 feet) tall at the shoulder. Female Alaskan moose, or cows, are smaller, averaging about 1.8 meters (5.9 feet) at the shoulder and weighing around 478 kilograms (1,054 pounds).
The antlers of a mature bull Alaskan moose are known for their broad, palmate shape. They typically have an average span of 1.8 meters (5.9 feet). The widest recorded antler spread was 2.1 meters (83 inches). Antlers are shed annually, usually in December and January, and regrow each summer.
Factors Influencing Their Growth
Several factors influence the size an individual Alaskan moose can achieve. Age is significant; male moose do not reach full body growth until approximately eight years old. Antler size also increases with maturity, with the largest antlers typically produced when bulls are between 10 and 12 years of age.
Sex plays a clear role, with males being notably larger and heavier than females; male Alaskan moose can be 40% heavier. Diet and nutrition are also important, as moose require a daily intake of high-quality forage to support their growth. Alaskan moose consume large quantities of willow, birch, and aspen twigs, sedges, and aquatic vegetation. They need about 9,770 kilocalories (32 kg) daily from their diet.
Habitat quality directly influences physical development. Areas with abundant food resources and favorable climates, such as river deltas and floodplains, tend to support moose with larger antlers and overall body size. Genetic predisposition also influences an individual moose’s growth potential. However, environmental factors like food availability and population density can affect how these genetic traits are expressed.
Alaskan Moose Versus Other Moose
The Alaskan moose is the largest subspecies compared to other North American moose, including the Eastern, Northwestern, and Shiras moose. For instance, Shiras moose, found in the Rocky Mountains, are the smallest North American subspecies. Their bulls typically weigh up to 544 kilograms (1,200 pounds) and stand about 1.8 meters (6 feet) tall at the shoulder.
The Northwestern moose is the second-largest North American subspecies, with bulls potentially reaching nearly 726 kilograms (1,600 pounds) and standing over 1.98 meters (6.5 feet) at the shoulder. Eastern moose, found in eastern Canada and the northeastern United States, are somewhat smaller. Males typically weigh between 363 to 635 kilograms (800 to 1,400 pounds) and stand 1.5 to 2 meters (5 to 6.5 feet) tall.
Alaskan moose also surpass most European moose, which are generally smaller. Males weigh up to 600 kilograms (1,320 pounds) and stand between 1.5 and 2 meters (5 to 6.5 feet) at the shoulder. While some Siberian moose subspecies can approach the size of Alaskan moose, Alces alces gigas consistently represents the upper end of the size spectrum for the species.