Moose are large herbivores that primarily consume plant matter. Their diet is diverse and changes throughout the year, adapting to available vegetation in their varied habitats. This adaptability allows them to extract necessary nutrients from different food sources across seasons.
Terrestrial Vegetation
Moose largely depend on terrestrial plants, particularly woody browse, for their sustenance. They are browsers, preferring to eat leaves, twigs, and bark from trees and shrubs rather than grazing on grasses. Common woody species in their diet include willow, aspen, birch, maple, and balsam fir. They consume parts like buds, shoots, and leaves during warmer months, shifting to tougher twigs and bark in colder periods. While bark offers limited nutritional value, it helps fill them up when other options are scarce.
Moose also consume herbaceous plants, known as forbs. Although grasses are not a significant part of their diet, they may consume them, especially in spring when their nutrient content is higher.
Aquatic Plants
Aquatic vegetation plays a role in the moose diet, particularly during warmer months. These plants, such as water lilies, pondweeds, hornwort, and horsetails, are rich in essential minerals. Aquatic plants contain higher levels of sodium and iron compared to terrestrial browse, which is important for antler development in males and milk production in females. They are also more digestible and provide more nutrition per unit than terrestrial plants. Moose seek out shallow lakes, ponds, and wetlands for these plants, with beaver ponds being particularly important feeding grounds due to their mucky bottoms that favor aquatic plant growth.
Seasonal Dietary Shifts
The diet of moose undergoes significant changes throughout the year, driven by seasonal availability and nutritional demands. In spring and summer, their diet is rich in succulent leaves, new shoots, and aquatic plants, helping them regain weight lost during winter and build up fat reserves. As autumn progresses and temperatures drop, moose gradually shift away from aquatic vegetation and green leaves, incorporating more twigs and woody browse into their diet. Winter forces them to rely almost exclusively on woody browse, such as twigs and bark, which are lower in nutritional value and harder to digest.
Foraging Behavior
Moose have developed specific behaviors to obtain their diverse diet. They are adept at browsing, using their flexible lips and long legs to reach vegetation high off the ground, up to eight feet. When feeding on aquatic plants, moose can submerge their heads, and even their entire bodies, for extended periods, closing their nostrils to prevent water entry. They can dive to considerable depths to access submerged plants.
Their digestive system is adapted for processing tough plant matter; as ruminants, they possess a four-chambered stomach that hosts specialized microorganisms. These microbes ferment the fibrous plant material, breaking down cellulose and aiding in nutrient absorption.