Orangutans are pros at calling to each other through dense foliage. A new study examined orangutans' long-distance calls, which travel as far as 1 kilometer, in Borneo’s rainforest in Indonesia. Listening in on the calls from three males and observing how females reacted, researchers confirmed an earlier finding that orangutans know who the call is coming from. They also report in Ethology that the females react differently based on the context of a male's call: For example, they tended to ignore long calls that the males emitted following a disturbance, such as a tree falling, but those with infants—-like the one here—moved away from “spontaneous” long calls, which the males may emit to attract mating females.
ScienceShot: Orangutans Decipher Each Other's Calls