New book expands field data available on orangutans

Great Ape Trust of Iowa scientist Dr. Serge Wich and three other internationally respected orangutan experts have edited a book set for release in the United States this month that, for the first time, compares data collected at every known orangutan research site and examines the information to discern differences and similarities among orangutan species, subspecies and populations.

Scientists are aware of significant variation in the behavior, morphology and life histories of orangutans, found only on the islands of Sumatra and Borneo, but the comparative approach in Orangutans: Geographic Variation in Behavioral Ecology and Conservation provides a theoretical framework to explain them, according to Wich and his co-editors. The data analyzed in the book, collected for Sumatran orangutans (Pongo abelii) Bornean orangutans (Pongo pygmaeus) and their subspecies, provide a foundation for conservation action plans to save the critically endangered wild orangutans from extinction, and also emphasize the effects of human settlement on orangutans and their habitat.

Wich and his esteemed co-editors – Dr. S. Suci Utami Atmoko, a biology research associate and lecturer at Universitas Nasional in Jakarta, Indonesia, and a member the IUCN-SSC Primate Specialist Group; Tatang Mitra Setia, who has studied Indonesian primates since 1979 at the Ketambe Research Center and is the dean of the biology faculty at Universitas Nasional; and Dr. Carel P. van Schaik, a Dutch primatologist who is a professor and director of the Anthropological Institute and Museum at the University of Zürich, Switzerland – all have extensive backgrounds tracking and studying wild orangutans.

For this book, they brought together more than 70 of the world's leading orangutan experts to rigorously synthesize and compare the data, quantify the similarities and differences, and seek to explain them.

"Instead of just getting really good people with data from one population, we sought data from many scientists," Wich said. "This gives us the advantage of looking at differences site by site."

The comparison gives scientists a better understanding of how such ecological factors as fruit availability in the forest, for example, affects various orangutan populations. "By taking a look at differences in ecology, it's easier to understand variation," Wich said. "That's why looking at one taxon is a very useful approach."

Having such data available in one source "makes us think differently about conservation issues," he continued. "If all orangutans were all the same, maybe saving a population here and a population there is enough to conserve the species, but if they're different, conservation measures should reflect that. This site-by-site collection of data makes it much more strategic for us to consider all of these differences. What we are trying to do is not only preserve numbers, but also take geographic variation into account."

The book points out not only differences between Sumatran and Bornean orangutans, but also their subspecies. There are three known Bornean orangutan subspecies – Pongo pygmaeus pygmaeus, Pongo pygmaeus wurmbii and Pongo pygmaeus morio – and no known subspecies of Sumatran orangutans.

Great Ape Trust's Dr. Rob Shumaker, one of the scientists invited to contribute chapters to the volume, said the book is "extraordinarily important," in part because it fills a void in both the quality and quantity of comparative data available on orangutans. "The comparative literature that exists on orangutans is sparse when compared to what we know about chimpanzees, for example," said Shumaker, who also pointed to a "very notable and unusual level of collaboration among scientists who worked together to create chapters."

"It's rare to achieve this level of collaboration and cooperation among field researchers," he said. "It's very difficult to find that when looking through literature on other species and other types of great ape."

Shumaker said that collectively, scientists contributing chapters to the book paint a clearer picture of the flexibility and range of orangutan behavior in the wild and provide important insight to researchers working with captive orangutan populations. Though he has studied the mental abilities of orangutans for more than 20 years, Shumaker said the information presented in the book "revolutionizes my perspective and thinking into the level of variation we might expect in orangutans in captivity."

Another contributing author, Dr. Anne Russon, said the book is noteworthy not only because it systematically attempts to consider orangutan biology and conservation across the whole of the orangutan's rage, but also because of the sweeping scope of the research presented.

"It is simply vast," said Russon, a professor of psychology at Glendon College, York University, Toronto, who since 1989 has studied intelligence and learning in ex-captive Bornean orangutans rehabilitated and released to free forest life.

"It required the work of a huge number of scientists and conservationists, with a very wide range of expertise and covering a time span of more than 30 years, to develop this kind of view of orangutans," she said. "This effort identified similarities – and perhaps more important, differences – among orangutans that were either unknown or at best only hinted at in the past."

Though some of the data reported in the book's chapters remain suggestive because they were not collected to today's methodological standards, "that points the way forward, in the sense of indicating what aspects of orangutan biology now need attention," Russon said.

Source : Great Ape Trust of Iowa