November 1, 2013
Your Brain Hates Snakes
I hate snakes. No, really. I pride myself on being the classic tomboy who will pick up a spider and hide it in her brother’s room for a good laugh (hypothetically speaking), I spent my summers in the woods, collecting frogs and wrecking havoc. However, the sight of a mere garter snake always sent me sprinting for the house.
I think this response is completely rational. OBVIOUSLY a garter snake puts me in great personal danger. Furthermore, snakes are just evil. Their lack of limbs makes them untrustworthy. When was the last time you encountered a friendly snake? The only nice one that comes to mind is the toy snake from Disney’s Toy Story, and he isn’t even real. Other than that, they are usually portrayed as villainous and deceitful.
Thankfully, I am not alone in my fear. Many people detest snakes. They aren’t cuddly creatures, per say. They are sneaky. And slithery. And some other S words that makes me cringe. My mom likes to say that they give her the “heebie jeebies.” But, why? Why do we fear some creatures and not others? Is it childhood experience, or perhaps something more?
It turns out this revulsion towards snakes may be embedded in our brains. In the redOrbit article “Fear Of Snakes May Have Triggered Evolution Of Close-Range Vision,” the author details that neuroscientists in Brazil and Japan may have found evidence supporting the idea that our human ancestors developed sharper eyesight in order to counteract the threat of snakes.
Researchers, specifically neuroscientists, were able to demonstrate that there are certain nerve cells in the brain of Rhesus macaque monkeys that are stimulated by photographs of snakes. Previous research has shown that monkeys fear snakes, however, “[these] results show that the brain has special neural circuits to detect snakes, and this suggests that the neural circuits . . . have been genetically encoded.”
Think of it as a built in alarm system. The minute that monkeys encounter a snake, these neurons in their brain begin going crazy. Something along the lines of “RED ALERT, RED ALERT. DANGEROUS SLITHERING BEING. PREPARE FOR OVER-EXAGGERATED NINJA RESPONSE.” From an evolutionary perspective, this was probably quite useful. Encounters with large snakes would have likely been unpleasant and possibly fatal.
Scientists believe that snakes may have “exerted strong selective pressure on primates.” At one point in history, snakes and mammals were likely the same size. They were natural enemies and forced to evolve accordingly.
While I don’t love the idea of snakes having an influence on my DNA, I appreciate the built-in fear. Who knows when a garter snake might decide to chase me down and strangle my ankle? One must always be prepared. So, if my mammal brain contains the same genetic alarm system as the Rhesus monkey, hopefully I will be on red alert and in ninja mode during my next snake encounter.
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