<em>Vital lessons at orang-utan 'Oxbridge':  The discovery of a group of privileged primates teaching each other sophisticated behaviour hints at the way human intellect has evolved </em>

Robin McKie, science editor.  Sunday April 9, 2006 <a href="http://observer.guardian.co.uk/uk_news/story/0,,1749987,00.html" target="new">The Observer</a>

Suaq Balimbing, in the Kluet swamps, is one of Sumatra's least attractive destinations. It has mud, a profusion of biting insects, oppressive heat, and little else. To humans, it is a place to avoid. But to the island's wild orang-utans, Suaq is a magnet. It is the simian equivalent of Oxbridge, a place to obtain a privileged education so they can stand out among their peers.

At Suaq they learn from other wild orang-utans how to make tools, to play jumping games and even to blow kisses to each other at night. Stay at Suaq and you become a special animal.

And that, say researchers - writing in the latest issue of Scientific American - has critical implications for humans. The existence of a place in the wild where apes undergo intense social learning suggests a route by which humans acquired their intelligence, as we evolved from primitive apemen to Homo sapiens.
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'Our analyses of orang-utans suggest that not only does culture - social learning of special skills - promote intelligence, it favours the evolution of greater and greater intelligence in populations over time,' says Carel van Schaik, director of the Anthropological Institute at Zürich University.

In other words, apemen got their big brains by hanging about in groups, learning social skills and tool-making - like orang-utans. And as the generations passed, apemen with bigger brains did better and better in these groups. The end result was Homo sapiens.

Schaik and his colleagues began observing orang-utans in the wild several years ago and chose Suaq because the swamp supplies abundant food for orang-utans all year round. As a result, the site is visited regularly by dozens of them. 'It is great for orang-utans, but hell for researchers,' Schaik adds.

And it was here the scientists made their first, astonishing discovery. The orang-utans of Suaq create and wield a variety of tools, carefully fashioning twigs and sticks to poke into ant, termite and bee nests to collect insects and honey and to prise open nuts and fruits. Often a twig is held in an orang-utan's mouth, then delicately moved around a nest. Then it is withdrawn and the honey licked off.

Chimpanzees have occasionally been observed using twigs in a similar fashion, but orang-utans in the wild have never been seen to make and use tools before. Crucially, orang-utans at neighbouring sites do not display such skills.

The orang-utans of Suaq also say good night to their families by blowing a loud raspberry noise which is often amplified by cupping hands. In addition, they use leaves as protective gloves or napkins. Again, such behaviour is unique to Suaq, a place that has its own distinctive orang-utan culture.

All these habits were learnt from other orang-utans and the benefits have clearly made it worthwhile for them to stick together in large numbers despite their natural tendency to be reclusive and reserved. The skills they pick up at Suaq - like honey eating - clearly gives them an advantage in surviving life in the wild. Dozens of them gather there to cavort in trees overhanging the swamp.

'And when an orang-utan in Suaq has acquired more of these tricks than its less fortunate cousins elsewhere, it has done so because it had greater opportunities for social learning throughout its life,' adds Schaik. 'In brief, social learning may bootstrap an animal's intellectual performance onto a higher plane.'

It is the orang-utan equivalent of going to a good school, an act that can confer critical advantages in later life just as it does with a human child. However, there is more to social learning than explaining why some youngsters get on in life and others do not, Schaik argues.

Over millions of years individual animals of high intelligence do best in top-stream institutions and will be favoured by natural selection. Thus our ancestors picked up the habit of social learning millions of years ago and slowly evolved bigger brains as a consequence. It was all about education, education, education.

Such an account does not explain why humanity's ancestors, alone among the great apes, evolved extreme intelligence, however. Other factors must be involved, otherwise orang-utans would be as clever as humans today. On the other hand, the remarkable behaviour of orang-utans in rich cultural settings like Suaq makes the gap between ourselves and the great apes seem less profound than it might otherwise appear, adds Schaik. 'Quite simply, culture promotes intelligence,' he states.