Orang Utans:the most intelligent Apes?

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http://www.timesonline.co.uk/tol/news/uk/article1654998.ece

From The Sunday Times

April 15, 2007

 

Chimps knocked off top of the IQ tree

Jonathan Leake and Roger Dobson

 

ORANG-UTANS have been named as the world's most intelligent animal in a

study that places them above chimpanzees and gorillas, the species

traditionally considered closest to humans.

 

The study found that out of 25 species of primate, orang-utans had developed

the greatest power to learn and to solve problems.

 

The controversial findings challenge the widespread belief that chimpanzees

are the closest to humans in brainpower. They also suggest that the ancestry

of orang-utans and humans may be more closely entwined than had been

thought.

 

" It appears the orang-utan may possess a privileged status among human

kindred, " said James Lee, the Harvard University psychologist behind the

research. " It is even possible that an orang-utan-like forager occupied a

pivotal link in the chain of descent leading to man. "

 

Both orang-utans and chimpanzees share about 96% of their DNA with humans,

although molecular studies suggest that chimpanzees are more closely

related.

 

The study comes at a time when orang-utans are endangered as never before.

Once widespread throughout the forests of Asia, they are now confined to

just two islands, Sumatra and Borneo, and are highly endangered as a result

of habitat loss and poaching.

 

Lee's work involved collating a series of separate studies into the

intelligence of different primate species. However, his research first had

to overcome a much greater hurdle: would it be possible to compare different

species of primates at all?

 

Spider monkeys, for example, have developed brains to cope with a

fast-moving life in the tree tops, while slow lorises are small and

leisurely nocturnal hunters.

 

The conventional belief is that comparing the intelligence of different

species is meaningless because separate evolution over millions of years

will have given them very different brains.

 

Lee, a junior psychology researcher at Harvard, found that in primates, at

least, different rules seem to apply — the development of one set of mental

skills seems to prompt the primate brain to develop other mental abilities

as well.

 

" A primate genus with a high rank in an experiment testing particular mental

abilities appears to have high ranks in all of them, " said Lee.

 

He also found that the single most important factor in deciding a species'

intelligence was simply the size of its brain: " The correlation of brain

size with mental ability found in humans appears to extend throughout the

primate order. "

 

This " remarkable finding " suggests, he said, that all primate brains work in

much the same way, however they have evolved, allowing comparisons between

species.

 

Lee's research threw up some other surprises, too. Gorillas, for example,

emerged as less intelligent than spider monkeys while baboons, often

considered relatively bright, were ranked 14th.

 

Recent field work by Carel van Schaik, a Dutch primatologist who is now at

Duke University, North Carolina, appears to bear out Lee's findings.

 

Studying orang-utans in Borneo, he found them capable of tasks well beyond

chimpanzees' abilities — such as using leaves to make rain hats and

leakproof roofs over their sleeping nests. He also found that in some

food-rich areas the creatures had developed a complex culture in which

adults would teach youngsters how to make tools and find food.

 

He and Lee both suggest that the key factor in such developments is the

orang-utans' life-style, spent mostly in the tops of trees where there is

little risk from predators. This has allowed them to establish long and

settled lives similar to humans' and also to develop culture and

intelligence.

 

In his own research papers, Van Schaik has suggested that since the

ancestors of modern orang-utans split from the human lineage about 15m years

ago, the seeds of human culture must go back at least as far.

 

Chris Stringer, professor of human origins at the Natural History Museum in

London, agrees that the sociable lifestyles of primates are the driving

force behind the development of intelligence. " Primates and early humans had

not got the claws and teeth of predators so they had to rely on brainpower

to communicate and protect themselves, " he said. " They are sociable

creatures and living in small groups seems to have driven brain

development. "

 

The idea that sociability and intelligence are linked is borne out by

research into the relative brain power of diverse animal groups including

cetaceans (whales and dolphins) and birds.

 

Dr Vincent Janik, of the sea mammal research unit at St Andrews University,

said that some dolphin species had developed the ability to communicate far

beyond that of great apes. " Dolphins have some abilities that great apes

don't have, such as copying new sounds. No primate apart from humans can do

that, " he said.

 

*Additional reporting: Max Colchester*

 

*Non-human primates in order of intelligence *

 

*1* Orange-utan

 

*2* Chimpanzee

 

*3* Spider monkey

 

*4* Langur

 

*5* Macaque

 

*6* Mandrill

 

*7* Guenon

 

*8* Mangabey

 

*9* Capuchin

 

*10* Gibbon

 

*11* Baboon

 

*12* Woolly monkey