Updated
Gorillas see the world much as we do: they have forward-facing eyes with good depth perception and full colour vision, which helps them judge distances when climbing and pick out ripe fruit and young leaves. Their hearing is similar to ours, tuned to the low rumbles and calls they use to keep in touch in dense forest. Their sense of smell is somewhat better than a human’s, and silverbacks give off a strong odour when excited or stressed. Here is how each sense works and what it means when you meet gorillas on a trek.
Sight
Like other great apes, gorillas have trichromatic colour vision, seeing reds and greens much as people do. Combined with binocular vision, this helps them choose the most nutritious leaves, shoots and fruit and move safely on steep ground. Vision is also central to their social life: gorillas read faces, postures and gaze, and a direct stare is a threat signal. That is why visitors are told to look down if a silverback approaches. See our guide to how gorillas communicate.
Hearing
Gorilla hearing covers a range close to human hearing. In thick vegetation, where group members are often out of sight, sound matters a great deal: soft contact rumbles, grunts and the drumming of a chest-beat, which can carry up to about a kilometre, keep the group together and warn rivals. Habituated gorillas quickly notice unfamiliar or loud human voices, which is why trekkers are asked to speak softly.
Smell, taste and touch
Gorillas use smell to assess food and probably to recognise individuals and the presence of other groups. Adult males produce a pungent smell from glands under the arms, especially when excited, which researchers think may signal stress or arousal to others. Taste guides food choice, as gorillas avoid bitter, toxic plants and favour certain tender stems, barks and fruits. Touch is important between mothers and infants and in play, and gorillas have sensitive, ridged fingertips for handling food. See our guide to gorilla fingerprints and identification.
What it means on a trek
Gorillas notice you long before you see them. Move slowly, keep voices low, avoid strong perfumes or insect repellent sprays near the group, do not use flash, and avoid staring at the silverback. You may notice the strong musky smell as you approach a group, a sign that the gorillas are close. The permit costs US$800, or US$600 in April, May and November. See our guides to gorilla tracks and signs and what makes a silverback.
Frequently asked questions
Yes, they have colour vision similar to humans.
Somewhat better than ours; they use it for food and probably to recognise others.
Glands under the arms release a strong odour, especially when the male is excited or stressed.
A direct stare is a threat signal among gorillas.
