Moose, the largest members of the deer family, are herbivores found across northern North America, Europe, and Asia. Their large size, often exceeding 1,000 pounds and six feet tall at the shoulder, necessitates a specialized diet to sustain their body mass and support reproduction. As browsers, moose adapt their intake to the availability and nutritional value of vegetation in their diverse habitats. This dietary specialization is important for their survival in environments with significant seasonal changes.
Key Dietary Components
Woody vegetation provides the bulk of moose sustenance. They consume twigs, leaves, and bark from a variety of trees and shrubs. Preferred woody browse includes willow, aspen, birch, maple, pin cherry, and mountain ash. Moose choose foliage rich in crude protein, structural fiber, and minerals like calcium, zinc, and potassium.
Aquatic vegetation forms another important part of the moose’s diet, especially during warmer months. Plants like water lilies, pondweeds, and sedges are consumed for their high sodium content, a mineral often scarce in terrestrial browse. Moose are skilled swimmers, diving over 18 feet to access submerged plants using a specialized snout that closes their nostrils underwater. While lower in energy than some terrestrial plants, aquatic vegetation is highly digestible and provides crucial minerals.
Beyond woody and aquatic plants, moose also consume other vegetation, though these make up a smaller portion of their diet. They may graze on forbs, grasses, and occasionally fungi. Fecal analyses indicate sedges can be important in their diet, even if direct observation is less frequent. Moose saliva can reduce the toxicity of certain fungi in grasses, allowing them to consume these plants without adverse effects.
Seasonal Variations in Diet
A moose’s diet changes significantly throughout the year, driven by plant availability and nutritional content. In spring and early summer, as winter recedes, moose transition to fresh, new growth. This period is important for regaining weight lost during winter, supporting antler regrowth in males, and milk production in females. They consume succulent leaves, tender forbs, and young grass shoots, which are rich in protein and energy.
As summer progresses into early fall, moose continue to feed on terrestrial vegetation, including green leaves of birch, willow, and aspen. They also increase aquatic plant consumption, which helps them meet sodium and mineral requirements. This intake of nutrient-dense foods allows moose to build fat reserves for colder months.
During fall, as temperatures drop and leaves die, moose gradually shift their diet. While still consuming remaining green leaves, they increasingly rely on woody browse. This transition prepares them for winter, as aquatic and herbaceous plants diminish. Moose may also migrate to areas where woody food sources are more abundant.
Winter presents the most challenging period for moose, as their diet consists almost exclusively of woody browse, bark, and sometimes conifer needles. This includes twigs from species like willow, birch, aspen, and balsam fir. Winter browse is lower in nutritional value and more difficult to digest compared to summer forage. Moose must consume large volumes of these woody materials to meet their energy needs, often spending 10-13 hours a day foraging. They may also strip bark from trees like mountain ash and maple as food.