June 10, 2008

Monkeys Found That Know How To Fish

Researchers have discovered groups of long-tailed macaque monkeys in Indonesia that have learned how to fish.

According to researchers from The Nature Conservancy and the Great Ape Trust, groups of long-tailed macaques were observed four times over the past eight years scooping up small fish with their hands and eating them along rivers in East Kalimantan and North Sumatra provinces.

The macaques are known to eat fruit and forage for crabs and insects, but fishing from rivers is a documented first for the species.

Erik Meijaard, one of the authors of a study on fishing macaques, said it was exciting to see new behavior in the species after such a long time. "It's an indication of how little we know about the species."

"It was unclear what prompted the long-tailed macaques to go fishing," said Meijaard, who is a senior advisor at The Nature Conservancy.

Meijaard said it showed a side of the monkeys that is well-known to researchers"”an ability to adapt to the changing environment and shifting food sources.

"They are a survivor species, which has the knowledge to cope with difficult conditions," Meijaard said Tuesday. "This behavior potentially symbolizes that ecological flexibility."

Meijaard wrote that other primates, including Japanese macaques, chacma baboons, olive baboons, chimpanzees and orangutans, have exhibited fishing behaviors.

Agustin Fuentes, a University of Notre Dame anthropology professor who studies long-tailed macaques, or macaca fascicularis, on the Indonesian island of Bali and in Singapore, said he was "heartened" to see the finding published because such details can offer insight into the "complexity of these animals."

"It was not surprising to me because they are very adaptive," he said. "If you provide them with an opportunity to get something tasty, they will do their best to get it."

Fuentes said he has seen similar behavior in Bali, where he has observed long-tailed macaques in flooded paddy fields foraging for frogs and crabs.

"It affirms my belief that their ability to thrive in urban and rural environments from Indonesia to northern Thailand could offer lessons for endangered species," said Fuentes.

"We look at so many primate species not doing well. But at the same time, these macaques are doing very well," he said. "We should learn what they do successfully in relation to other species."

Further research was needed to understand the full significance of the behavior, according to Fuentes and Meijaard. Among the lingering questions are what prompted the monkeys to go fishing and how common it is among the species.

The Nature Conservancy researchers have twice observed macaques catching fish in 2007. Wich spotted them doing it two times in 1998 while studying orangutans.

The study appeared in last month's International Journal of Primatology.

The Nature Conservancy volunteers Anne-Marie E. Stewart, Chris H. Gordon and Philippa Schroor, and Serge Wich of the Great Ape Trust were the other authors of the paper.

Image Courtesy Wikipedia


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