Male orangutans do not only plan their journey, they also inform others of their trip a day ahead.
Anthropologists in the Zurich University discovered that aside from orangutans in captivity, orangutans in the wild also display planning abilities in order to attract females and ward off male rivals by announcing the route they will be taking on.
It was previously believed that only humans had the ability to plan trips ahead, while animals have no sense of direction and time. However, in the past years, experiments conducted with great apes in captive have displayed good memory of past events and ability to plan for their future trips. The researchers carried out a study and observed great apes in the wild if they also have these skills. They followed orangutans in the dense tropical swamplands of Sumatra for many years.
Though, adult male orangutans are the ones who travel the most through the forest alone, they maintain social communicating relationships with others by producing long, loud sounds. Similar to megaphones, the orangutan’s cheek pads serve as an amplifier. Females that hear faint sounds come nearer to maintain contact. Non-dominant males, then again, ward off after hearing the sound.
Carel van Schaik, lead author of the study from the Anthropological Institute and Museum at the Zurich University, wrote, "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. We then actually observed that the males traveled for several hours in approximately the same direction as they had called."
If their travel route changes, the other orangutans responds appropriately to the long sound of the previous evening, though no new, long call was produced. Appropriate responses mean females coming nearer and males warding off from where the sound is heard.
The study was published in the online journal PLOS One.
