Over the last 7 years I have worked with many small snakes (under 6 foot). A few were nippy juveniles, many more were rescues that had been mistreated by former owners, and some were just demon children who would strike at the glass if I passed 10 feet away.
I don't think the 'jerking the hand back' is in any way cowardly. I firmly believe this is a hard-wired instinct in humans, even though the thinking, rational part of our brain knows that that 16" colubrid or juvenile python is harmless, old self-preservation gut reactions die hard--somewhere deep down, your body 'knows' this may be a potentally lethal venomous animal. This is no different than seeing an object come flying by your head and ducking or raising your hands, even if you know it's only a nerf ball, it's almost impossible to just freeze and not react to it.
It took a good three years for me to stop my urge to yank away; as a poster above said, it's very easy to harm small/juvenile snakes doing this. On one rather horrifying occasion, I reached into a front-opening cage to remove a juvenile corn; it struck at me and managed to get ahold of the end of my middle finger just as I jerked away--The snake went flying over my shoulder across the room and landed (thank God) on a pile of laundry. I don't think any one wants to get bitten, but it comes along with the hobby. I will admit that getting bitten did make me a little jumpy around my snakes, but I got over it, and learned to watch body language closer, which did result in less bites.
I have heard many herpers (almost all male) state that only 'chickens', 'sissies', or 'cowards' are afraid of getting bitten, or that real herpers don't try to avoid bites. I have always ignored these childish comments, they sound like a 'look how tough/manly I am' pissing contest to me.
Bites from even medium size snakes (large colubrids, ball/spotted/childrens pythons, sub adult boa constrictors, etc.) can be an unpleasent affair, the teeth are sharp, they hurt, and in my case, the saliva causes itching almost as painful as the bite. But I don't think I, nor anyone else in the hobby should feel or ever be made to feel that we are less qualified snake keepers because we exercise caution around small/juvenile snakes, or any size snake for that matter.
Sorry about the run on reply, thanks!
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Heather J. Martin
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1 Solomon island ground boa, female
1 Green iguana, male
1 Green anaconda, juvenile
1 Burmese python, 9', female
2 juvenile het for albino BCI