Head to head
Bornean Orangutan vs Western Gorilla
Orangutans and gorillas are both great apes, but they sit on different branches of the family and on different continents. The orangutan is the only great ape from Asia and the most tree-bound; the gorilla is the biggest of all the apes and lives on the ground in Africa. Their contrasting sizes, diets, and social lives make them a useful pair for seeing how varied the great-ape way of life can be.
| Bornean Orangutan | Western Gorilla | |
|---|---|---|
| Continent | Asia (Borneo and Sumatra) | Africa (Congo Basin and West Africa) |
| Where it spends its time | High in the forest canopy | Mostly on the ground, knuckle-walking |
| Adult male weight | About 50 to 90 kg | About 140 to 200 kg (silverback) |
| Main food | Fruit, plus bark, leaves, and insects | Leaves, stems, and pith, with fruit when available |
| Social life | Largely solitary; adults mostly live apart | Stable groups led by one dominant silverback |
| Male display | Cheek pads and a long call carrying up to a kilometre | Chest-beating, strutting, and roaring |
| Reproduction | Slowest of any mammal, 7 to 8 years between births | About 4 years between births |
| Conservation status | Critically Endangered (all three species) | Critically Endangered (western gorilla) |
Orangutan vs Gorilla: common questions
Which is bigger, an orangutan or a gorilla?
The gorilla, by a wide margin. A dominant silverback gorilla typically weighs 140 to 200 kg and stands about 1.7 m tall, making it the largest primate alive. A large male Bornean or Sumatran orangutan weighs around 50 to 90 kg, roughly half as much, and females of both species are smaller still, with a female orangutan often only 30 to 50 kg. The orangutan's arm span is enormous relative to its body, which can make it look bigger in the trees than it is, but on the ground next to a gorilla the size difference is obvious. Gorillas are also far more heavily muscled, especially through the chest, shoulders, and jaw.
Why do orangutans live alone while gorillas live in groups?
It comes down mostly to food. Orangutans depend heavily on fruit, which in the Southeast Asian rainforest is scattered widely and appears unpredictably, often in irregular mast years. A large group travelling together would quickly strip any one fruiting tree and leave everyone hungry, so orangutans spread out, and an adult can range alone efficiently. Gorillas eat mainly leaves, stems, and pith, which are abundant and evenly distributed through the forest, so a whole family group can feed in the same patch without competing much. Reliable, spread-out food makes group living affordable for gorillas, and it also provides protection, since a silverback can defend the group against predators and rival males.
Are orangutans and gorillas closely related?
They are both great apes, in the family Hominidae along with chimpanzees, bonobos, and humans, but the orangutan is the most distant member of that family from the rest. The orangutan lineage split off around 15 to 19 million years ago, well before the African apes diverged from one another. Gorillas, chimpanzees, bonobos, and humans form a tighter African cluster, with gorillas branching off roughly 8 to 10 million years ago. So a gorilla is genetically closer to a human than it is to an orangutan, and the orangutan is the odd one out, which fits its separate continent and its many distinctive features.