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An adult male, adult female, and infant Assam macaque from Nepal. (Courtesy of Laxman Khanal)

Nepal’s Assam Macaque Is Its Own Beast




Laxman Khanal was lost.

Chasing after a troop of elusive Assam macaque cliff monkeys along the dense forest of Api Nampa Conservation Area at the far western end of Nepal, he lost track of his local assistant. A mere glimpse of the monkey troop and he couldn’t hold back. He had to chase them. And why wouldn’t he? Three days of bumpy bus rides and another three spent on arduous jungle hikes had finally led to this moment.

After a desperate chase-off, he finally could rest and stare at this troop. The terrain was terrifying. One misstep and his body may tumble straight down to the cascading stream at the base of the mountain. Steep cliffs are the favourite spots of these monkeys — the best place to evade large carnivores like leopards. Somehow managing to stay still, he observes the monkeys; and as they depart, Khanal scoops up their fresh stool samples. It’s an absolute gold mine for his research.

The westernmost recorded troop of Assam macaques in Darchula, Nepal. (Courtesy of Laxman Khanal)

“It was literally a do or die situation for me,” he said. “Either collect samples or your research is for nothing!”

The cost? Just minor bruises. “I could for sure take it. Come on, I am an ecologist,” he grinned. But for Khanal, a primatologist and molecular analyst at Tribhuvan University, scrambling for monkeys in unforgivable terrain was just a footnote of his two-year relentless quest. In early 2021, his work was published in the journal Zoological Research with an audacious claim: ‘Molecular research suggests Nepal population of Assam macaques (Macaca assamensis) to be a distinct species’. This could send shockwaves across the world of taxonomy.


The Nepal Population of Assam Macaques (NPAM) is a highly protected monkey species, not in the least because they look so similar to Rhesus Macaques, a common, urbanized, and occasionally aggressive monkey found across the Indian subcontinent. Assam Macaques are more elusive and shy, bigger, and heavier, with longer tails and genitals than the Rhesus.

It was based on these physical attributes that in the late 1990s, Mukesh K. Chalise, one of Nepal’s pioneer monkey researchers, speculated that Nepalese flocks of Assam Macaques may actually be a different species.