Gorillas are not a type of monkey; they belong to a distinct group of primates known as apes. Both groups share a distant common ancestor within the Primate order, but their evolutionary paths diverged millions of years ago. This separation led to fundamental differences in their anatomy, size, intelligence, and lifestyle. Understanding these differences involves looking beyond superficial similarities to their taxonomy and biology.
The Core Difference: Apes Versus Monkeys
Gorillas are classified as Hominidae, or great apes, a family that also includes chimpanzees, orangutans, and humans. Monkeys, in contrast, are divided into two main groups: Old World monkeys (Cercopithecidae) and New World monkeys (Platyrrhini), both of which are distinct from the ape family.
This classification reflects a significant evolutionary split, with apes generally exhibiting a larger brain-to-body size ratio and greater cognitive complexity than most monkeys. They often display complex social structures and problem-solving abilities. Apes are recognized for having a more upright posture and a skeletal structure adapted for suspension and climbing that differs from the quadrupedal framework of most monkeys.
Another high-level difference lies in the presence of a tail, which is a near-universal feature among monkeys, used for balance or gripping. Apes, including gorillas, have completely lost the external tail structure, having only vestigial internal tail bones. The evolution of the ape body plan reflects a shift toward locomotion that does not rely on a tail for stability.
Key Anatomical Distinctions
Gorillas are the largest living primates, with male silverbacks weighing up to 400 pounds and standing around six feet tall, which is vastly larger than the biggest monkeys. This size difference is compounded by extreme sexual dimorphism in gorillas, where males are significantly larger and more robust than females, a trait less pronounced in most monkey species.
The architecture of their torsos and shoulders is highly distinct, reflecting different modes of movement. Gorillas and other apes have a broad, flattened chest and highly mobile shoulder joints designed for hanging and climbing. Monkeys typically have a narrower chest and a skeletal structure suited for running along the tops of branches.
Limb proportions further separate the two groups, relating to their terrestrial and arboreal habits. Gorillas possess arms that are longer than their legs, which is an adaptation for their knuckle-walking gait. Monkeys, particularly Old World species, generally have forelimbs and hindlimbs that are more equal in length, or sometimes longer legs, which facilitates running and leaping.
Variations in Habitat and Locomotion
Gorillas are primarily terrestrial and use knuckle-walking locomotion, where they support their upper body weight on the knuckles of their hands. While they may climb trees, particularly the younger and smaller individuals, adult gorillas spend most of their time on the forest floor of Central African forests.
Most monkey species, by contrast, are arboreal, meaning they spend the majority of their lives in the tree canopy. Their tails provide balance and, in some New World species, a prehensile grip. When monkeys do move on the ground, they typically use a quadrupedal running gait, moving with their palms flat on the surface rather than their knuckles.
Gorillas are herbivores with a diet heavily focused on bulk consumption of foliage, such as leaves, stems, and shoots, which is a factor in their large size and limited daily travel distance. Monkeys, however, have a far wider range of habitats across Africa, Asia, and the Americas, and their diets are much more varied, often including fruits, insects, and small vertebrates.