Why do male orangutans make long calls?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

An illustration of a female Bornean orangutan (Pongo pygmaeus) with long reddish-brown fur, hanging from tree branches with one arm extended upward and one leg hooked over a branch. A scale bar at the bottom shows lengths of 30 centimeters and 12 inches for size reference. — orangutan Female orangutans (*Pongo*) have the longest breeding interval of any mammal, giving birth on average once every eight years.

Adult male orangutans produce a "long call"—a sequence of roars that can last up to five minutes and travel as far as 2 km (1.2 miles)—to serve two primary social functions:

Spacing: The call helps maintain distance between males, who are generally solitary and avoid one another.
Attraction: It serves to attract sexually receptive females.

These vocalizations are made possible by a specialized throat pouch that acts as a resonating chamber. While adult males possess the prominent cheek pads and throat pouches necessary for this behavior, subadult males typically lack these features and do not perform the long call. Females almost never produce the full sequence of the call.1