Gorillas, the largest of the primates, are primarily terrestrial animals, spending most of their lives on the ground. However, they are fully capable of arboreal activity. Gorillas frequently ascend trees for specific, functional purposes, though they do not live permanently in the canopy like smaller primates. Their massive body size dictates a strong preference for the ground, but climbing remains an important behavior utilized for foraging and sleeping.
Primary Habitat and Terrestrial Life
The majority of a gorilla’s existence is spent foraging and traveling across the forest floor, driven largely by their immense body mass. Adult males, or silverbacks, can weigh up to 220 kilograms, a weight few tree branches can reliably support for extended periods. This physical constraint has led to their specialized form of locomotion known as knuckle-walking, where they move quadrupedally with their weight supported on the knuckles of their hands.
Their diet, consisting mostly of terrestrial vegetation like leaves, stems, and pith, further anchors them to the ground. Gorillas inhabit dense forest undergrowth where their food is abundant and easily accessible. Their long, powerful arms assist in locomotion and defense, and also serve to pull down and manipulate the dense foliage they consume.
Arboreal Activity: When and Why Gorillas Climb
While adult silverbacks are largely restricted to the ground due to their bulk, climbing is common for lighter group members. Females and younger gorillas climb much more frequently than the heaviest males, using trees for temporary resting and specific foraging needs. Their lighter weight allows them to access branches that would immediately break under a silverback.
The primary motivation for climbing is to access preferred food sources, particularly fruits out of reach from the ground. Gorillas will ascend as high as 15 meters to reach concentrated patches of ripe fruit. They may also use a tree for brief observation or to rest during the day, positioning themselves above the forest floor. This arboreal activity is temporary, as the animals always return to the ground for most daily activities.
Nesting Habits: Where Gorillas Sleep
Every evening, gorillas construct a new sleeping platform, a daily ritual essential to their existence. This nest-building behavior is a learned skill consistent across all age groups, except for infants who sleep in their mother’s nest. The fresh nest provides insulation, comfort, and protection from ground-dwelling parasites during their sleep period.
The choice of nest location is based on an individual’s size and environmental conditions. Ground nests, circular platforms of bent vegetation, are typically constructed by heavier silverbacks who require maximum support. Lighter individuals, such as females and juveniles, often build arboreal nests in stable trees for safety from predators and ground moisture. This temporary tree-dwelling for the night is the most consistent arboreal habit of the species.
Species Differences in Climbing Behavior
The two main gorilla species exhibit differences in climbing frequency, linked closely to their size and diet. Eastern Gorillas, including Mountain Gorillas and Eastern Lowland Gorillas, are generally the largest subspecies. Mountain Gorillas are often the heaviest and live in habitats with fewer sturdy canopy trees, making them the most strictly terrestrial of the species.
Conversely, Western Gorillas, especially the Western Lowland Gorilla, are smaller and more agile. Western Lowland Gorillas consume a higher proportion of fruit in their diet, necessitating more frequent and higher climbing to access canopy fruit. This smaller size and dietary difference mean Western Lowland Gorillas engage in arboreal foraging and travel more often than the heavier Eastern species.