Monkeys can spot a snake almost instantly, and researchers now know why.
Dr. Nobuyuki Kawai from Nagoya University in Japan discovered that it’s the scaly skin of snakes that triggers this quick reaction.
His research sheds light on how primates, including humans, evolved to detect threats based on specific visual clues.
For millions of years, snakes have been one of the most dangerous predators to primates. This long history of danger has shaped our ability to recognize them quickly.
Even human infants and monkeys that have never seen a snake before react with fear when shown pictures of snakes. Dr. Kawai’s study, published in Scientific Reports, delves deeper into this fascinating behavior.
To understand how monkeys recognize snakes, Kawai conducted a series of experiments.
In one test, monkeys were shown a board with nine images, one of which was different from the others. The monkeys were trained to find the unique image to receive a reward.
When a snake image was hidden among pictures of salamanders, the monkeys quickly identified the snake. However, they took longer to find a salamander in a group of snakes. This showed that snakes grabbed their attention much faster than the harmless amphibians.
But Kawai wanted to know more: What exactly about snakes caught the monkeys’ attention? To test this, he edited images of salamanders to give them snakeskin.
Surprisingly, the monkeys reacted to these altered salamanders just as quickly, or even faster, than to actual snakes.
“The monkeys didn’t respond to salamanders, even though they have a similar long body and tail like snakes,” Kawai explained. “But as soon as we gave the salamanders snakeskin, the monkeys reacted immediately.”
This finding suggests that the visual cue of scales is key to how monkeys recognize snakes as a threat. Kawai believes that this ability evolved over millions of years to help primates survive in environments where snakes posed a serious danger.
“During evolution, our primate ancestors likely developed a visual system that could quickly identify scales, which are unique to snakes,” Kawai said. “This adaptation played a crucial role in keeping them safe.”
Kawai’s research not only reveals how monkeys identify threats but also provides insights into how vision and the brain have evolved in animals, including humans. By understanding these evolutionary traits, scientists can gain a deeper understanding of how our ancestors survived—and how their adaptations continue to shape us today.
