Why Are Monkeys So Aꜰʀᴀɪᴅ Of Snakes?

EVER wonder why snakes inspire such ꜰᴇᴀʀ? A new study on monkeys says the brain has specific cells that fire off rapid warnings when confronted with slithery ᴅᴀɴɢᴇʀ.

Certain neurons respond “selectively” to images of snakes, and they outpace comparable neurons that react to visuals of faces, hands or geometric shapes, the researchers said.

The report in the Proceedings of the National Academy of Sciences offers new evidence to support the notion that primates evolved keen vision skills so they could sᴜʀᴠɪᴠᴇ the ᴛʜʀᴇᴀᴛs snakes pose in the jungle.

The research was done using two young macaque monkeys that were born on a national monkey farm in Japan. Researchers said they believe the monkeys had no chance to ᴇɴᴄᴏᴜɴᴛᴇʀ snakes prior to the experiment.

Scientists sᴜʀɢɪᴄᴀʟʟʏ ɪᴍᴘʟᴀɴᴛᴇᴅ micro-electrodes in a part of the brain known as the pulvinar, which is involved in visual attention and the fast processing of ᴛʜʀᴇᴀᴛᴇɴɪɴɢ images. Then they showed the monkeys various colour images on a computer screen, including snakes in various positions, ᴛʜʀᴇᴀᴛᴇɴɪɴɢ monkey faces, pictures of monkey hands and simple shapes like stars or squares.

Seeing a snake caused the brain to fire off rapid ꜰᴇᴀʀ responses that were unparalleled by those observed in reaction to faces, hands or shapes. Researchers found that of about 100 neurons that fired off when presented with at least one of the image types, 40 per cent had the largest response to snakes.

Though ꜰᴇᴀʀ of snakes may not be innate, noticing them more than other phenomena may be hard-wired by evolution, said Lynne Isbell, an evolutionary biologist from the University of California, Davis. That heightened attention, research has shown, can lead to early and resilient learned behaviour, such as ꜰᴇᴀʀ-mediated avoidance. In other words, getting out of the way of snakes.

“The characteristics we have help us to see them better than other mammals can see them,” Isbell said. “Mammals in general are really good at picking up movement. But snakes lie in wait. They don’t move very much, so it’s crucial to see them before they see us and to avoid them.”


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