Gorillas are the largest living primates, inhabiting the forests of central and eastern Africa. Primarily herbivores, their diet in the wild consists overwhelmingly of plant material. Their feeding habits are adapted to their forest environments, allowing them to thrive on a wide array of vegetation. This plant-based diet provides the necessary energy and nutrients for their large body size.
Main Plant-Based Diet
The bulk of a gorilla’s diet is composed of various plant parts. They consume large quantities of leaves, stems, pith, and bark. For instance, mountain gorillas primarily feed on green plant parts, with leaves, shoots, and stems making up approximately 86% of their diet, while roots account for 7%, and flowers 3%. They are known to consume over 142 plant species, including fibrous vegetation like thistles, nettles, and bamboo shoots.
Gorillas are selective foragers, often choosing specific parts of a plant, such as the base and tips of young leaves, rather than consuming the entire plant. An adult male gorilla can consume more than 18 kg (40 lbs) of vegetation daily to meet its energy demands. This high volume of intake is necessary because the plant material they consume, while abundant, is often low in energy and nutritional quality, requiring them to eat continuously throughout the day. They rarely need to drink water, as they obtain sufficient hydration from the succulent vegetation they eat and morning dew.
Dietary Variations and Other Foods
Gorilla diets vary depending on the species, habitat, and seasonal availability of food. Mountain gorillas, found at higher altitudes, have limited access to fruits, which comprise a small percentage (around 2%) of their diet. Their diet remains relatively consistent year-round, focusing on tough leaves and stems that are readily available. In contrast, Western lowland gorillas, residing in forests with more fruit trees, incorporate a higher proportion of fruit into their diet, sometimes as much as 67% when available.
During dry seasons or periods of fruit scarcity, Western gorillas adapt by increasing their consumption of fibrous plants, seeds, and tree bark. Bark, for example, provides important minerals like sodium, which are crucial for muscle function and blood pressure regulation. Gorillas also supplement their plant-based diet with small amounts of animal matter, primarily insects such as termites, ants, caterpillars, and larvae. These invertebrates typically constitute less than 1% of their total food intake, offering a minor source of protein and other nutrients.
Gorillas have also been observed ingesting soil or mineral deposits, a practice known as geophagy. This behavior is thought to provide missing minerals not readily available in their plant diet, or to help neutralize potentially toxic compounds found in some vegetation.