Snake Sightings

Have you ever wondered why we humans are so spooked by the sight of a snake? Countless examples exist of how we fear and abhor serpents. Precious few people see a snake and do not feel an adrenalin rush and an urge either to whop it or to flee. You don't have to teach a kid to fear snakes—the dread comes naturally; it's deep in our DNA. For Christians and Jews, the origin of our exile from an edenic existence was caused by the scheming snake.

If you consider where we humans evolved (Africa), dangerous snakes were everywhere—cobras, vipers, and other such vermin. It's not surprising that our deep ancestors evolved fear of and ways to avoid snakes. A healthy fear, accompanied with an ability to quickly jump back served them well. They passed those jumping genes on to us.

Some recent research provides another genetic advantage that we humans have, and we apparently have snakes to thank for it: acute vision. Since snakes were such a threat to our ancestors, serpents literally helped us evolve the excellent eyesight that we have. We are endowed with forward-facing eyes, so our depth perception is superb... we can quickly tell just how far away that viper is. Our visual acuity surpasses most all other mammals. We possess first-rate color vision, so we can spot that camouflaged snake in the grass. My, what great eyes we have! The better to see you, Mr. Snake.

Snakes are not easy to detect. Their color often allows them to blend into their surroundings and they can appear to be a stick or a twining vine. It's quite possible that some early hominid species which might have otherwise evolved into something like humans, instead became extinct, because their limited visual acuity gave the advantage to those poisonous snakes.

Our extremely ancient ancestors—small, lemur-like creatures who lived among the dinosaurs—didn't need superb eyesight, because they were nocturnal critters. They didn't hang out in the daytime, because the dinosaurs ruled the day; so they survived by slinking around after dark. They also didn't bump into many snakes, who slept the night away.

As mammals came into the light—once the dinosaurs became extinct—they needed more acute vision, to avoid those creepy serpents. Some of them developed superb eyesight and passed the ability on down the line to us. So the next time you are repulsed by the sight of a snake, realize that it's an instinct you inherited from long ago, but also be thankful that your keen eyesight (which also lets you spot a gorgeous bird, on a limb off in the woods) may also be a gift from that loathsome snake in the grass.