The Los Angeles Times and other news outlets report that the brains of Japanese macaques (and possibly human beings) may be hard-wired to fear snakes
The results, published online Monday in the journalProceedings of the National Academy of Sciences, appear to support a theory that early primates developed advanced perception as an evolutionary response to being prey, not as an adaptation that may have made foraging or hunting easier.
Though fear of snakes may not be innate, noticing them more than other phenomena may be hard-wired by evolution, said Lynne Isbell, an evolutionary biologist fromUC Davis and one of the authors of the paper. That heightened attention, research has shown, can lead to early and resilient learned behavior, such as fear-mediated avoidance. In other words, getting out of the way of snakes. [. . . ]
The researchers used two monkeys raised in captivity that had no opportunity to encounter a snake. Probes measured responses to snakes, faces and hands of monkeys, and geometric shapes. More neurons responded to the snakes, and did so with greater strength and speed, the data showed.
This passage from Harold Frederic’s 1896 novel The Damnation of Theron Ware anticipates these results. In the following passage, Dr. Ledsmar, an evolutionary scientist, is leading the naive minister Theron Ware around various scientific exhibits in his house.
They moved out of the room, and through a passage, Ledsmar talking as he led the way. “I took up that subject, when I was at college, by a curious chance. I kept a young monkey in my rooms, which had been born in captivity. I brought home from a beer hall—it was in Germany—some pretzels one night, and tossed one toward the monkey. He jumped toward it, then screamed and ran back shuddering with fright. I couldn’t understand it at first. Then I saw that the curled pretzel, lying there on the floor, was very like a little coiled-up snake. The monkey had never seen a snake, but it was in his blood to be afraid of one. That incident changed my whole life for me. Up to that evening, I had intended to be a lawyer.”