Giraffes, known for their towering height and distinctive patterns, are herbivores. These majestic animals play a specific role in their ecosystems as browsers, focusing on leaves, twigs, and buds from trees and shrubs. Their specialized diet and foraging behaviors allow them to thrive in the diverse landscapes they inhabit.
Staple Vegetation
The primary food source for giraffes is leaves and shoots from trees and shrubs, relying particularly on Acacia species (now often classified as Vachellia or Senegalia). Giraffes also consume other woody plants, including species from the Combretum and Terminalia genera, as well as Grewia and wild apricot trees. They are selective eaters, selecting specific parts like leaves, flowers, and pods.
Giraffes can eat approximately 29 to 34 kilograms (65 to 75 pounds) of foliage each day. While their diet is mainly woody browse, they may also consume herbs, climbers, vines, and fruits seasonally. Occasionally, giraffes eat grass, which requires them to splay their legs or bend at the knees due to their height.
Specialized Foraging
Giraffes possess unique adaptations to access vegetation from heights unreachable by most other herbivores. Their long necks allow them to browse foliage up to 6 meters (20 feet) off the ground, reducing competition for food. A giraffe’s tongue is long, measuring between 45 to 50 centimeters (18 to 20 inches), and is highly dexterous and prehensile. This flexibility allows them to grasp branches and strip leaves, even maneuvering around sharp thorns.
The tongue’s dark pigmentation may offer protection against sunburn. Their thick lips and the tough papillae covering their tongue and inside their mouth provide a protective barrier against thorns. Their narrow muzzle assists in selecting individual leaves from between thorns. These adaptations allow giraffes to efficiently forage on thorny plants that deter other animals.
Nutritional Importance
The plants giraffes consume provide nutrients and hydration vital for their large size and unique physiology. Leaves are a rich source of protein, which is necessary for their growth and maintenance. Their diet also provides fiber, which is important for their digestive system. Giraffes are ruminants, possessing a stomach with four compartments, similar to cows, which allows them to efficiently digest plant matter through microbial fermentation.
The browsing diet also supplies a significant amount of moisture, allowing giraffes to go for extended periods without needing to drink water directly, as they obtain much of their water from their food. Giraffes also cope with secondary plant compounds, such as tannins, found in their preferred browse. Their saliva, rich in proline, helps bind these tannins, and their digestive system metabolizes them. Occasionally, giraffes may chew on bones, a behavior known as osteophagia, to supplement their diet with calcium and phosphorus when these minerals are scarce in their plant-based food.
Adapting to the Environment
A giraffe’s diet is dynamic, shifting based on seasonal availability and local environmental conditions. During wet seasons, when food is abundant, giraffes disperse more and consume a wider variety of new leaves and tender shoots from deciduous trees. In contrast, during dry periods, they often concentrate around remaining evergreen trees and tougher browse, as preferred food sources become scarce. Browsing time increases in the dry season due to the lower quality of available forage.
Giraffes also influence the vegetation structure of their habitats. Their browsing can stimulate the growth of new shoots and affect the height and shape of trees, particularly Acacia species. This continuous pruning can lead to a characteristic “waistline” on favored trees. Furthermore, giraffes contribute to seed dispersal by consuming seeds that pass through their digestive tracts and excreting them, aiding in plant regeneration and increasing vegetative cover. This process is important for maintaining biodiversity and the resilience of savanna ecosystems.