Can wild baboons recognize themselves in the mirror?

LONDON — When 112 wild baboons encountered mirrors for the first time in Namibia’s desert landscape, scientists watched eagerly. Would these clever primates recognize their own reflections, like humans and great apes do? International researchers in Namibia’s Tsaobis Nature Park, located on the edge of the Namib desert, recently tackled this question by studying wild baboons, and their findings tell us something fascinating about animal self-awareness.

When you spot something on your face in the mirror, like a smudge of chocolate or a stray eyelash, you naturally reach up to touch it. This simple act shows you recognize your reflection. Scientists call this the “mark test,” and it’s been used for 50 years to study whether animals can recognize themselves. Until now, these tests were mostly done with captive animals in small groups, which might not tell us how animals really behave in nature.

This study, published in Proceedings of the Royal Society B, had researchers try something completely new. Instead of studying zoo animals, they watched 112 wild chacma baboons in Namibia between May and October 2021. Rather than using paint or stickers that might stress out the baboons, they came up with a clever solution: laser pointers, like the ones teachers use in classrooms, but carefully selected to be completely safe for the animals.

For baboons living in the wild, mirrors are quite strange. Unlike zoo animals who might see reflective surfaces regularly, these baboons live in an arid environment where shiny surfaces are rare. Before starting their experiments, the researchers set up two medium-sized mirrors near water spots the baboons visited frequently, giving them time to investigate these novel objects.

The researchers conducted three types of tests using green and red lasers. First, they shined the laser on spots the baboons could easily see, like their hands or feet. Next, they aimed at places the baboons couldn’t see without a mirror, like their cheeks or ears. Finally, they conducted the mark test: would baboons notice and try to touch a laser mark on their face when looking in the mirror?

When baboons saw laser marks on their hands or feet, about two-thirds of them reached out to investigate. But when they could only see the mark in their reflection? Out of 135 mirror tests, only one baboon showed any reaction at all.

“The Chacma baboons we observed in Tsaobis Nature Park certainly enjoyed using the mirrors as a new toy, but throughout our study, they didn’t quite understand that the mirror’s reflection represented their own bodies and that the laser mark in the mirror image was, indeed, on themselves,” says study author Dr. Alecia Carter from University College London, in a statement.

The study revealed interesting patterns: male baboons were more curious about the marks than females, and younger baboons showed more interest than older ones. They also seemed to prefer green lasers over red ones, likely because the green dots appeared brighter.

While the baboons didn’t recognize themselves, they showed impressive intelligence in other ways. They quickly learned to use mirrors as tools for watching their surroundings, much like we use rearview mirrors in cars.

“Given the monkeys quickly familiarized themselves with their mirror image, it also suggests that they don’t consider their reflection to be a stranger,” says corresponding author Esa A. Ahmad.

By studying these wild baboons in their natural habitat, scientists have gained unprecedented insights into primate cognition. The research shows that while self-recognition might be unique to great apes and humans, other primates have their own sophisticated ways of understanding their environment.