Snakes Ignite Instinctive Fear Response in Primates

Monkeys, much like humans, possess an intrinsic capability to swiftly identify snakes, and recent research indicates that scales constitute a vital visual cue for primates when discerning these serpentine threats.

Cognitive scientist Nobuyuki Kawai from Nagoya University, Japan, conducted experiments involving three Japanese macaques (Macaca fuscata), which had no prior exposure to live reptiles or amphibians, having only encountered images of snakes in earlier studies. Predictably, the animals exhibited a significantly quicker response to images of snakes in contrast to salamanders within a reward-based identification task.

Remarkably, when the salamander images were augmented with a snakeskin overlay, the monkeys’ response times equaled those observed with actual snake images. This suggests that scaly textures serve as a crucial visual stimulus for recognition.

“While we previously demonstrated that both humans and primates can quickly recognize snakes, the specific critical visual features had yet to be discerned,” remarks Kawai.

Notably, the monkeys did not register a heightened response to salamanders, a species sharing a similar elongated morphology with snakes, until the images were modified to feature snakeskin. This lends credence to the hypothesis that primates might have evolved a specialized visual acuity for identifying snakes, informed by their evolutionary history.

These findings suggest that the capacity to recognize snakes is of paramount importance, as evidenced by the fact that snakes pose a considerable threat to humans, responsible for approximately 94,000 fatalities annually, starkly contrasting the mere 14 fatalities attributed to shark attacks in 2023.