A vacation always runs more smoothly when you plan ahead. And we humans aren't the only ones who make travel arrangements. A new study shows wild orangutans choose the direction of their trip in advance—and then communicate their plans to others. The work is in the journal PLOS ONE. [ Carel P. van Schaik, Laura Damerius and Karin Isler, Wild Orangutan Males Plan and Communicate Their Travel Direction One Day in Advance]
Mature male orangutans emit loud roars called long calls, audible more than a kilometer away. Studies suggested that long calls can announce the caller's identity, attracting females while warding off rival males. But do they transmit travel plans as well?
To find out, researchers monitored 15 wild males. While resting or feeding, the orangutans turned in different directions, and produced a total of over 200 long calls. When they eventually began to move, it tended to be in the direction they had faced while vocalizing. Additional long calls signaled changes in direction.
By planning and sharing their itineraries, the males influenced their peers. Females tended to move towards the caller's path, while subordinate males avoided it. For these apes, an impressive roar blazes a clear trail.
[The above text is a transcript of this podcast.]