Ape culture hints at earlier evolution

Orangutans show complex social behaviour

Decades of orang-utan watching has led scientists to believe that some of the animals have developed their own culture.

Using leaves and sticks to gather food and building sun covers for nests, are just some of the ways that orang-utans make their lives easier in the wild.

An international research project into the behaviour of these giant apes suggests there is extensive social contact between the animals.

The discovery could also help scientists understand how human culture developed.

Raspberries

Researchers investigated six sites in Borneo and Sumatra for wild orang-utan behaviours.

Some orangutans use tools like leaves to gather food or water.

They looked for signs of cultural activity, which would show the animals communicated closely with each other.

Culture can be described in many different ways, but the basic elements include labels, signals, skills and symbols.

The scientists found some orang-utan populations use leaves as protective gloves or napkins, swat insects with leafy branches and make "raspberry" sounds when going to sleep.

Some of the groups even play sport. During "snag-riding," the animals ride falling dead trees, grabbing vegetation before the tree hits the ground.

Human origins

The findings could shed light on how early human behaviour evolved.

The complex behaviour of orang-utans suggests human culture started to develop 14 million years ago, much earlier than thought.

At this time the ancestors of chimps and orang-utans diverged.

Professor Carel van Schaik from Duke University in Durham led one of the teams behind the study.

He said: "Culture requires more than just a mother-infant bond, but also extensive social contact, and orang-utans are at the low end of the sociability spectrum.

"While we were by no means certain that we would come up with any evidence for cultural variability, we ultimately identified 24 behaviours that likely represent cultural variants."