Not that I disagree with frankykeno's comment about Darwin's theories being a possible reason for humans' instinctive fear of snakes, you also have to take into account that there was a significant risk to early humans who settled mainly in the Nile river valleys which were tropical and did (do, still, lol) house venemous snakes in the form of snakes, which possibly could have added to the probably already present instinctive fear of snakes. A cow or buffalo will jump if you make a rattling sound near it even if it's never seen a rattlesnake or a snake of any sort before, after all, because of the evolution of rattles on rattlesnakes to warn buffalo not to step on them. I don't think it really takes all that long for a species to develop a life preservational instinct, does it?

Of course, I'm not arguing--just butting in to add that...I believe in Darwin's theories, I just like discussing this kind of thing. ^-^; saw this thread and it looked interesting. *science nerd?*