The moose (Alces alces) holds the designation as the largest extant species within the deer family worldwide. These massive ungulates are instantly recognizable by their immense size, characterized by long legs and a distinctive hump over the shoulders. Adult males, known as bulls, are especially impressive due to the massive, palmate antlers they grow and shed annually. The sheer scale of the largest specimens has generated significant interest in determining the absolute maximum size this species can attain in terms of both body mass and antler dimension.
The Alaskan Moose: The Largest Subspecies
The record-setting specimens almost exclusively belong to the subspecies Alces alces gigas, commonly known as the Alaskan or Yukon moose. This subspecies is geographically distributed across Alaska, the Yukon Territory, and portions of British Columbia. Alaskan moose bulls routinely stand over six feet tall at the shoulder, with some towering close to seven feet, and generally average around 1,400 pounds.
This size contrasts sharply with other North American subspecies, such as the Shiras moose found in the Rocky Mountains, which is smaller in body mass and antler spread. The size difference illustrates a biological principle where animals of the same species tend to be larger in colder, northern latitudes. These northern giants dominate the record books because their environment allows for the maximum expression of their genetic potential for growth.
Official Records for Weight and Antler Spread
Determining the largest moose ever recorded requires looking at two distinct metrics: maximum body weight and maximum antler size. The heaviest reliably confirmed specimen was a bull taken near the Yukon River in September 1897. This monumental animal had a shoulder height of 7 feet 8 inches (2.33 meters) and weighed 1,808 pounds (820 kilograms).
While there are historical reports of even larger bulls, some allegedly weighing over 2,600 pounds, these figures lack the necessary authentication to be considered official records. The 1897 Yukon specimen stands as the benchmark for maximum recorded biological size.
The official record for greatest antler spread belongs to a bull taken in December 1958 near Redoubt Bay on the Kenai Peninsula in Alaska. This animal’s antlers achieved an extraordinary spread of 80 5/8 inches (204.8 centimeters). The moose itself was not considered exceptionally large, weighing approximately 1,400 pounds, demonstrating that maximum body size and antler spread do not always coincide.
Another measure is the total score maintained by the Boone and Crockett Club, which accounts for volume and symmetry. The current world record for total score is held by a bull taken in the Yukon in 2013, scoring 263 5/8 points. This particular specimen had a greatest spread of 75 5/8 inches, illustrating that the highest total score is a combination of numerous measurements, not simply the width across the rack.
Scoring Systems: How Record Moose Are Measured
The standardization of large-game records is primarily managed by the Boone and Crockett Club, which uses a specific, detailed methodology to calculate a trophy’s final score. This system ensures that all entered specimens are measured uniformly and objectively. The process involves multiple measurements taken with a 1/4-inch flexible steel tape to the nearest one-eighth of an inch after a 60-day drying period.
The score is a composite of several factors, including the length of the main beams, the length of all qualifying points, and four separate circumference (mass) measurements taken along the beam. A point must be at least one inch long and longer than it is wide to be counted in the final tally.
The final score is not simply the greatest spread, which is recorded only as supplemental information. The inside spread of the main beams is the only spread measurement that contributes to the final score, and it is taken perpendicular to the axis of the skull. The final score is calculated by adding all lengths and circumferences, then subtracting any asymmetries between the left and right antlers to arrive at a net score.
Biological Factors Driving Extreme Size
The large size of the Alaskan moose results from specific biological and environmental factors. The most significant factor is the availability of high-quality forage throughout the long growing season in the northern boreal forests. Moose are prodigious consumers, relying on nutrient-dense browse like willow, birch, and aquatic plants to fuel their rapid growth and the annual regeneration of their heavy antlers.
The immense body mass is also an adaptation to the cold northern climate. A larger body has a smaller surface area-to-volume ratio, which helps the animal conserve heat more efficiently in subarctic conditions. Strong genetics, where natural selection favors the largest, healthiest bulls for breeding, further reinforces the trait for extreme size within the population. Maximum size is ultimately a product of a long lifespan combined with consistent access to ideal habitat and nutrition.