Food Preferences & Resources
The composition of the gorilla's diet varies by subspecies and seasonality.
- Western lowland gorilla (Gorilla gorilla gorilla): This subspecies consumes parts of at least 97 plant species. About 67% of their diet is fruit, 17% is leaves, seeds and stems and 3% is termites and caterpillars.
- Eastern lowland gorilla (Gorilla beringei graueri): This subspecies consumes parts of at least 104 plant species.
- Mountain gorilla (Gorilla beringei beringei): This subspecies consumes parts of at least 142 plant species and only 3 types of fruit (there is hardly any fruit available due to the high altitude). About 86% of their diet is leaves, shoots, and stems, 7% is roots, 3% is flowers, 2% is fruit, and 2% ants, snails, and grubs.
- Cross River gorilla (Gorilla gorilla diehli): This subspecies is not as well studied as the other subspecies. However their diet has been studied through their fecal matter and is known to include fruit, leaves, stems, piths, and some invertebrates.
- Gorillas are able to survive on vegetation such as leaves, stems, roots, vines, herbs, trees, and grasses but such vegetation has relatively low nutritional quality. Therefore, they must consume a larger quantity, but it is available year-round.
An adult male gorilla may consume more than 18 kg (40 lbs.) of vegetation per day.
Gorillas rarely drink in the wild because they consume succulent vegetation that is comprised of almost half water as well as morning dew.
Methods of Collecting Food
Gorillas can use their incredible strength to break apart vegetation. An adult male for example can shred apart a whole banana tree to get to the interior tender pith.
Gorillas are very selective foragers. They usually only eat parts of vegetation. For example they may eat only the leaves, pith, stalk, or roots of a particular plant. They use their agile lips and hand dexterity to manipulate the vegetation for the particular portion they want to consume.
Gorillas do not overexploit an area for food. They crop the vegetation in a manner that allows for quick replenishment to occur.
Gorillas have been documented using the hair on the back of their hands to absorb water and then sucking it.