September 12, 2013
Male Orangutans Plan Trips A Day In Advance, Share Info With Mates
Michael Harper for redOrbit.com - Your Universe Online
New research from the University of Zurich reveals male orangutans as quite the travel planners. Not only do these primates set out their routes a day in advance, they also share these plans with their travel mates.
More than any other similarity shared between humans and primates, Carel van Schaik, primatologist and lead author of the study, says this proves the orangutans are capable of thinking past the present and into the future. The orangutans’ long calls heard throughout the jungle, says van Schaik, are more than just alerts to family; they often include the travel itinerary of the next day’s journey.
This isn’t the first study to find orangutans plan out their travels, but it is the first to observe just how these primates prepare for the following day’s journeys. This resulting paper is published in the journal PLoS ONE.
“Our study makes it clear that wild orangutans do not simply live in the here and now, but can imagine a future and even announce their plans,” explained van Schaik in a statement. “In this sense, then, they have become a bit more like us.”
This discovery certainly wasn’t easy to come by. Van Schaik and team listened for “long calls” from 15 male flanged orangutans on 320 different days in the span of five years. After recording 1,169 of these long calls, the research team charted the movements of the primates and placed them on a map. After gathering this data, the team found male orangutans issue these calls on the evening before a journey to let other orangutans, either females, lower ranking males or even enemies, know where they’ll be heading. As the orangutans traveled, they issued even more long calls to keep their travel mates on track. The females in their ranks generally kept close and followed these calls.
“To optimize the effect of these calls, it thus would make sense for the male to call in the direction of his future whereabouts, if he already knew about them,” van Schaik said. “We then actually observed that the males traveled for several hours in approximately the same direction as they had called.”
Should the male change his mind while in the middle of a hike, a new and clearer call is sent out to announce the change. The team also observed that males don’t need to give their travel companions directions more than once. If no calls are issued the morning of a trek, the other orangutans stick to the path set out the night before.
The male flanged orangutans are able to make these long calls thanks to their cheek pads, pieces of flesh that amplify their calls throughout the dense jungles. These calls work to either alert weaker males of their impending arrival or attract females. While the researchers weren’t able to interpret the calls into specific directions, they do suggest the different calls could convey much more than warnings. Deeper voices, for instance, usually come from larger males. Therefore, the deeper the voice the more menacing a male could be to enemies.
Furthermore, the researchers say they haven’t yet discovered how these males are able to plan out their paths and how other orangutans can decipher these plans into directions. They did mention, however, that their research has shown these animals are capable of complex thought, foresight and planning.