The Alaska moose (Alces alces gigas) is the world’s largest subspecies, with adult males often exceeding 1,400 pounds and standing over six feet at the shoulder. This immense size dictates its role as a major herbivore across Alaska’s diverse habitats, from boreal forests to tundra riparian zones. Found across the state, the moose plays a significant part in the ecology by shaping vegetation through consistent browsing. To sustain its massive frame, the moose must consume a substantial amount of vegetation daily, forcing a dramatic shift in foraging habits between the seasons.
Summer Foraging and Aquatic Plants
The Alaskan summer brings an abundance of highly nutritious forage, allowing the moose to prioritize rapid growth and fat accumulation. During this season, their diet shifts to soft, leafy vegetation, including the leaves of woody shrubs, forbs, and grasses. They feed heavily on young, fresh shoots from trees like birch and willow, which are rich in easily digestible protein and energy.
A particularly important component of the summer diet is aquatic vegetation, such as pondweed and water lilies, which moose wade into lakes and ponds to access. While these submerged and emergent plants are often lower in calories than terrestrial leaves, they offer an important nutritional balance. Aquatic plants contain significantly higher concentrations of minerals, most notably sodium, which is a limiting nutrient in their upland diet. Consuming these sodium-rich plants allows them to meet their mineral requirements and provides a means to cool down in the water.
Winter Survival and Woody Browse
The harsh Alaskan winter, with deep snow cover, forces a complete change in the moose’s dietary strategy. With ground cover and deciduous leaves unavailable, the moose must rely almost entirely on “browse,” which consists of the twigs, stems, buds, and bark of woody plants. This winter forage is significantly lower in nutritional value and harder to digest than their summer greens.
The primary food source during this period is the tender, annual growth of shrubs such as willow, birch, and aspen. Moose use their prehensile lips and strong jaws to strip the bark and bite off the ends of these woody branches. This diet is a survival necessity, providing just enough energy and fiber to keep the animal alive until spring. The moose’s height gives it a distinct advantage, allowing it to reach browse up to eight feet above the snow line.
Nutritional Requirements and Consumption Volume
To power their large bodies, adult moose must consume a tremendous volume of food, eating between 40 and 60 pounds of vegetation daily during the summer months. This high volume of forage is necessary to meet their daily caloric needs, which can be as high as 23,000 kilocalories. The moose is a ruminant, possessing a four-chambered stomach that allows it to process and extract nutrients from this high-fiber diet through fermentation.
This complex digestive system is particularly suited for a diet of woody browse, but it requires the moose to spend long periods ruminating, or chewing their cud, to break down the tough plant matter. The animal’s large size and metabolic demands also drive its year-round search for specific nutrients, especially sodium. This mineral, obtained largely from aquatic plants in the summer, is essential for nerve and muscle function and can influence a cow’s reproductive success. The constant need for both high-calorie vegetation in summer and bulk fiber in winter defines the moose’s persistent, high-volume foraging behavior.