Wildebeest are large, herbivorous mammals inhabiting Africa’s vast savannas and grasslands. Also known as gnus, these creatures are recognized for their distinctive appearance and important role in their ecosystems. Their diet consists almost exclusively of grass, which heavily influences their behavior, movements, and impact on the environment. There are two main species: the blue wildebeest and the black wildebeest, both are primarily grazers.
The Grass-Based Diet
Wildebeest are highly specialized grazers, with their diet composed almost entirely of grass. They show a strong preference for short grasses, which their broad, blunt muzzles are uniquely adapted to harvest efficiently. This specialized mouth shape allows them to consume short green grass that other grazing animals might find difficult to access. Among the grasses they favor are red oat grass (Themeda triandra), Rhodes grass (Chloris gayana), and star grass (Cynodon plectostachyus), particularly when these are abundant and nutrient-rich during the wet season.
These large herbivores consume substantial amounts of vegetation daily. They spend much of their day grazing, moving and feeding throughout the daylight hours. While most active during cooler morning and late afternoon periods, they also graze under moonlight, resting during midday heat.
Their grazing habits are beneficial for the grasslands, helping to maintain their health and biodiversity. Wildebeest often graze alongside other species, such as zebras, which consume taller, coarser grass, thereby exposing the shorter, more nutritious shoots that wildebeest prefer. They are also drawn to burnt areas, where fresh, succulent grass shoots quickly regenerate.
Seasonal Eating Habits and Water Needs
The diet of wildebeest adapts significantly to the changing seasons, especially between the wet and dry periods. During the wet season, when grasses are lush and abundant, wildebeest primarily feed on nutrient-rich grasslands. They actively seek out grazing areas with high phosphorus content, which is particularly important for lactating females.
As the dry season progresses and fresh green grass becomes scarce, wildebeest may supplement their diet with other plant parts, such as leaves, shoots, and shrubs. Water availability is an essential factor for wildebeest survival, as they require regular access to drinking sources. A blue wildebeest typically drinks 9 to 12 liters of water every one to two days and can only endure a few days without it.
This dependence on water strongly influences their migratory patterns, compelling them to constantly move in search of both water and suitable grazing areas. Their annual migration routes are often dictated by rainfall patterns, leading them to regions where short grasses thrive. During dry periods, they typically remain within 10 to 15 miles of a water source. Their highly efficient digestive system is important for extracting the maximum amount of nutrients from the grasses, providing the energy needed for their extensive migrations and breeding seasons.
Role in the Ecosystem
Wildebeest play an important role in shaping the savanna grassland ecosystem. Their extensive grazing helps to reduce the amount of overgrown vegetation, which in turn reduces the risk of destructive wildfires. By keeping the grass cover low, they contribute to the landscape’s ability to store carbon in the soil.
The movement of large wildebeest herds also helps to aerate the soil and enrich it with nutrients through their dung. This natural fertilization promotes the growth of diverse plant species and aids in grassland regeneration. Their grazing also creates space for new and varied plant growth, which benefits other animal species by improving habitat quality. Because of these widespread effects on biodiversity and grassland health, wildebeest are considered a keystone species in their environment.