"The rather uncomfortable feeling most of us have when we're around snakes is evidence of how this ancient experience continues to influence us today. Throughout the long prehistory of our species and those that preceded it, snakes were a mortal threat. And so we learned our lesson. Others didn't, but that had a nasty habit of dying. So natural selection did its work and the rule--beware of snakes--was ultimately hardwired into every human brain. It's universal. Go anywhere on the planet, examine any culture. People are wary of snakes. Even if--as in the Arctic--there are no snakes. Our primate cousins shared our long experience and they feel the same way: Even monkeys raised in laboratories who have never seen a snake will back away at the sight of one."
— Daniel Gardner (The Science of Fear: Why We Fear the Things We Shouldn't--and Put Ourselves in Greater Danger)