Giraffes primarily browse on leaves, buds, and shoots from various woody plants. Their impressive height allows them to access foliage unreachable by most other ground-dwelling animals.
Key Tree Species
Giraffes predominantly feed on the leaves and twigs of Acacia trees. These trees are a significant food source due to their nutritional content and wide distribution across African savannas. While Acacia trees are known for their sharp thorns, giraffes have developed specific adaptations to navigate these defenses. Beyond Acacia, giraffes also consume foliage from other prominent tree genera, including Combretum, Terminalia, Mimosa, and wild apricot trees.
Acacia trees provide essential nutrients, including calcium and protein. Some Acacia species employ additional defenses, such as releasing bitter tannins that deter prolonged browsing or harboring stinging ants within their thorns. Giraffes are able to selectively browse to avoid areas where these chemical defenses have been activated.
How Giraffes Forage
Giraffes forage effectively due to physical and behavioral adaptations. Their remarkable height allows them to reach foliage up to 6 meters (20 feet) from the ground. A key adaptation is their long, prehensile tongue, which can extend up to 45-50 centimeters (18-20 inches). This dexterous tongue wraps around leaves and shoots, allowing giraffes to pluck them while skillfully maneuvering around thorns.
Their tough, leathery lips and hardened papillae lining their mouths provide further protection against sharp spines. A thick, sticky saliva also lubricates food and coats ingested thorns, minimizing irritation to their digestive tract. Giraffes are selective in their browsing, adapting their feeding methods based on the plant’s defenses. Female giraffes tend to browse at lower heights, while males often reach higher into the tree canopy.
Other Plants in Their Diet
While trees form the majority of their diet, giraffes also consume other plant types, especially when preferred tree foliage is scarce. Their diet includes various shrubs, vines, herbs, and seasonal fruits and flowers.
Giraffes can eat grasses, but this is less common due to the awkward posture required to reach the ground, which also makes them vulnerable to predators. In times of stress or scarcity, giraffes have been observed eating the bark off branches. They also chew on old bones, a behavior known as osteophagy, likely to obtain essential minerals like phosphates and calcium.
Giraffes as Ecosystem Engineers
Giraffes significantly influence the ecosystems they inhabit as ecosystem engineers. Their browsing habits directly impact tree growth patterns, often shaping them into characteristic “giraffe pruning” or “waistline” forms. This selective feeding can create open spaces within dense woodlands by reducing the growth of certain tree species.
The feeding patterns of giraffes also contribute to seed dispersal and pollination, affecting plant diversity and regeneration. Their browsing helps maintain a balance between grasslands and woody vegetation, influencing savanna structure and composition. Research indicates that giraffe browsing can even stimulate new shoot production in some plant species, demonstrating a complex interaction.