The moose, the largest species in the deer family, is a massive herbivore inhabiting the boreal and temperate forests of the Northern Hemisphere. These solitary animals thrive in regions with extensive forest and wetland habitats, which influences their varied diet. Due to their immense size—adult males can weigh over 1,500 pounds—a moose requires significant sustenance, consuming between 40 and 60 pounds of forage daily during peak feeding season. Their survival relies on a feeding strategy that transitions between terrestrial and aquatic food sources throughout the year.
Primary Terrestrial Food Sources
Moose are classified as browsers; their diet consists mainly of the leaves, soft shoots, and twigs of high-growing woody plants and shrubs, contrasting with grazers that primarily eat grass. This specialized feeding habit allows them to efficiently strip vegetation using their flexible upper lip and powerful jaws. During warmer months, the majority of their caloric intake comes from nutrient-rich deciduous leaves and forbs.
They prefer young, succulent growth, which provides high concentrations of protein and digestible energy. Common woody browse species include willow, aspen, birch, and mountain ash. Willows often make up a significant portion of their summer diet. When fresh leaves are unavailable, they turn to the soft, young twigs and bark, though these are less nutritious.
The Essential Role of Aquatic Vegetation
Seeking out lakes, ponds, and wetlands is a characteristic summer behavior for moose, driven by a specific nutritional need. While terrestrial plants provide energy, they are often deficient in sodium, an element required for proper nerve and muscle function. Aquatic vegetation, such as pondweed, water lilies, and horsetail, accumulates high concentrations of this mineral.
Moose wade into the water, often submerging their heads completely to graze on these plants from the bottom. Their nostrils are adapted with valves that shut to prevent water from entering while they feed underwater. This behavior replenishes sodium stores depleted during the winter months. The consumption of aquatic plants may account for up to half of their diet during periods of active feeding.
How Diet Changes with the Seasons
The moose diet shifts dramatically between summer and winter, a transition crucial for survival in northern climates. Summer is focused on maximizing nutrient intake from leaves, fresh shoots, and aquatic plants to build substantial fat reserves. An adult moose can increase its body weight by up to a quarter during this time to prepare for the scarcity ahead.
As autumn progresses and leaves fall, the diet shifts almost entirely to woody browse, consisting of the twigs and bark of trees and shrubs. This winter forage is significantly lower in nutritional value, often yielding only one-third of the energy of summer food sources. The moose must then rely on finding areas with dense, accessible young growth, which is easier to digest than older, tougher branches.
To survive this period of scarcity, moose utilize both metabolic and behavioral adaptations to conserve energy. They become less active, moving slowly and resting more often to reduce the energy expenditure required for movement in deep snow. Their digestive system is also adapted to process the high-fiber, low-quality browse, allowing them to extract maximum nutrients from tough cellulose over a long period.