Communication and Perception
Male Sumatran orangutans are capable of long, exceptionally loud calls (called "long calls") that carry through forests for up to 1 km. The "long call" is made up of a series of sounds followed by a bellow. These calls help males claim territory, call to females, and keep out intruding male orangutans. Males have a large throat sac that lets them make these loud calls. They may also pull small trees and limbs down to add a crashing sound along with the call. Sumatran orangutans vocalize with grunts, grumbles, and squeaks when they meet each other, and young orangutans squeak, bark and scream. Both adults and young make a variety of sounds with their lips and throats, including sucking, burping, and grinding their teeth.
Communication Channels: visual ; tactile ; acoustic
Perception Channels: visual ; acoustic