New ape species revealed in all its majesty

In 1842, Queen Victoria visited London Zoo, where Jenny, a female orangutan, made an indelible impression on her, writes Richard Collins.

The creature, Victoria remarked, was “frightful, painfully, disagreeably human”. The animal’s uncanny facial resemblance to a human evoked an intuitive and disturbing sense of kinship between the

monarch and this great ape. Jenny also impressed Charles Darwin. She was equally fascinated by him and the images of herself in the mirror he had brought along.

‘Orang-utan’ means ‘man of the woods’ in an Indonesian language; these hairy primates are tree dwellers.

The most arboreal of the great apes, they subsist mainly on fruit. Tracking them is difficult.

We were four days in the steamy rainforests of Borneo before our guide managed to locate one. Some researchers we happened to come upon showed us where to look.

Otherwise we would not have seen any.

To get enough food, an orangutan must forage alone over a wide area. The other great apes, the gorillas and chimpanzees, live in groups.

Pooling their knowledge and displaying their skills, they learn the tricks of the trade from each other.

Such opportunities are fewer for the more solitary orangutans, perhaps cramping their intellectual development.

Males are much bigger than females; a mature daddy might tip the scales at 90kg. His size is a response to competition; males fight for access to females. The dominant one gets to mate with every available female in his area.

In Victoria and Darwin’s day, and for the next 150 years, zoologists thought that all
orangutans belonged to a single species.

However, as populations were studied in depth, significant differences were identified between Bornean and Sumatran ones.

In 1996, the two were classified as separate species. Their ancestors, it’s believed, diverged from each other about 400,000 years ago. The big news this month is that researchers have identified a third species.

The orangutans of South Tapanuli have been isolated for millennia from their cousins
elsewhere in Sumatra.

The area they inhabit is separated from other forest regions by a large lake. The primates there have lived apart from the rest of their kin for 10,000 to 20,000 years.

That’s long enough for them to develop what Charles Haughey might have called ‘Tapanuli solutions to Tapanuli problems’. They don’t look that different, apparently, from the ordinary Sumatran species.

Their hair is fuzzier, females have beards, and mature males sport distinctive moustaches. The calls are unique and, unlike orangutans elsewhere, the Tapanulies eat caterpillars.

The death of an adult male sealed the case for separate species designation. The animal died in 2013 in a conflict with local people.

Distinctive features of his skull and teeth were identified and he has become the type-specimen of his kind. Genetic samples taken from 37 individuals, and detailed physical examinations of 33 adult males, clinched the argument for speciation.

Despite Queen Victoria’s distress, orang- utans are not our closest animal relatives.

That distinction goes to the two species of chimpanzee, with which we shared a common ancestor about seven million years ago. Our ancestral connection with orangutans is a little older.

The line which led to us diverged from the one leading to them around 9m years ago.

Most insect and spider species have yet to be described. New kinds of bird amphibian, and even the occasional mammal, come to light from time to time.

It’s not so surprising, perhaps, that the Tapanuli orangutan, despite its being such a close relative, should not have come to light until now.

A Natar et al, ‘Morphometric, Behavioural and Genomic Evidence for a New Orang-utan Species’. Current Biology, November 2017.


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