Researcher Solves Night Monkey Mystery in Colombia

When Sebastián Montilla was 10 years old, he shined a lantern into a tree on his father's coffee farm and locked eyes with a creature that would change his life. A night monkey with enormous red eyes stared back before disappearing into the darkness.

That childhood encounter launched a nearly 20-year obsession. Montilla became a biologist dedicated to studying the only nocturnal primates in the Americas, animals so elusive that science knows surprisingly little about them.

"I'm very surprised by the fact that they have gone unnoticed for so long," Montilla told Mongabay. "It's astonishing because at midnight they are moving right past our houses and we don't even notice."

Night monkeys evolved massive round eyes with retinas 50% bigger than their daytime cousins to navigate in darkness. Unlike solitary nocturnal primates in Asia and Africa, these monkeys form lifelong pairs and raise up to three offspring together.

But their nighttime lifestyle made them nearly impossible to study in the wild. Most research came from laboratories and zoos, leaving huge gaps in understanding their behavior and habitat.

Montilla spent his career filling those gaps. He followed the monkeys through countless nights, discovering how moonlight affects their activity and documenting their diets and preferred habitats.

His latest breakthrough challenges everything scientists thought they knew about where different night monkey species live. The prevailing theory said the Andean mountains separated species at 1,000 meters elevation.

Montilla never bought it. "It's a bit ambiguous to think there's an imaginary line at 1,000 meters, and that a monkey above 1,000 meters is going to say, 'Oh no, I'm not going to go past 999 meters,'" he explained.

Between 2022 and 2025, he collected droppings from 92 locations across Colombia and extracted DNA. The results revealed something unexpected: the Magdalena River, not the mountains, separates two nearly identical species.

Why This Inspires

This discovery shows how childhood wonder can fuel lifelong purpose. A curious kid with a lantern became the world's leading expert on creatures most people never see.

His work matters beyond academic journals. Night monkeys face serious threats from cattle ranching, oil palm plantations, mining, and the illegal pet trade. Knowing exactly where each species lives helps conservationists protect the right habitats.

Montilla even helped create the first management plan for conserving Andean night monkeys in his home region of Quindío. The boy who used to lie under trees watching monkeys sleep now leads efforts to ensure they survive.

His research proves that some of nature's most important mysteries hide in plain sight, waiting for someone curious enough to look up.

One childhood encounter with glowing red eyes in the darkness sparked decades of discovery that could save five species.