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Mysterious monkey re-discovered in Borneo

January 20, 2012
Simon Fraser University
Researchers were stunned to rediscover one of the rarest primates in Borneo, the grizzled langur, thought by many to be extinct.

Miller's grizzled langur. Brent Loken, a PhD student in SFU's resource and environmental management program, discovered a rare monkey in the Bornean rainforest last June that many thought was extinct.
Credit: Image courtesy of Simon Fraser University

Simon Fraser University PhD student Brent Loken was hoping to capture images of the elusive Bornean clouded leopard when he set up a camera trap in the rainforest. Instead, he made the re-discovery of a lifetime.

Reviewing time-lapse photos taken at a mineral lick in the Wehea Forest of East Kalimantan last June, he and his fellow researchers were stunned to see an animal they didn't recognize. The pictures showed Miller's grizzled langur, one of the rarest and least-known primates on the island of Borneo, and also a species many suggested was extinct or on the verge of extinction.

"It was a challenge to confirm our finding as there are so few pictures of this monkey available for study," says Loken, who is in SFU's resource and environmental management program. "The only description of Miller's grizzled langur came from museum specimens. Our photographs from Wehea are some of the only pictures that we have of this monkey."

Loken's work is featured in a paper being published online this week in the American Journal of Primatology (print version, March 2012).

A former secondary-school principal and science teacher, Loken holds both Trudeau and Vanier scholarships. He spends up to six months each year in Borneo where he runs Ethical Expeditions, a non-profit organization he co-founded to help the indigenous Wehea Dayak people fight back against deforestation. The island has lost 65 per cent of its rainforest, largely due to palm oil plantations and coal mines.

"Finding Miller's grizzled langur in a forest outside of its known geographic range highlights how much we don't know about even the basic ecology of this monkey," says Loken. "We need more scientists doing research in Borneo to help us learn about understudied species such as Miller's grizzled langur and clouded leopards. The rapid degradation of Borneo's forests makes it difficult to learn about and adopt conservation strategies in time to protect species."

Loken's camera traps were part of a larger biodiversity study he organized in collaboration with the local Wehea Dayak community to investigate the diversity and abundance of animals that were living in this remote forest.

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Journal Reference:

  1. Lhota, Stanislav, Loken, Brent, Spehar, Stephanie; Fell, Eric, Pospěch, Alexandr; Kasyanto, Nunuk. Discovery of Miller's Grizzled Langur (Presbytis hosei canicrus) in Wehea Forest confirms the continued existence and extends known geographical range of an endangered primate. American Journal of Primatology, 2012 DOI: 10.1002/ajp.21983

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Simon Fraser University. "Mysterious monkey re-discovered in Borneo." ScienceDaily. ScienceDaily, 20 January 2012. <>.
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