About sexing baby snakes???

I have several colubrid snakes that are fairly young (at most 8 months old). I took them to a pet store and asked if the "herp expert" could sex them. He said they had to be around two years old before one could tell. My question is how do alot of the advertisers on these classified adds know they have 4 males and 3 females of a sort when they are still very young? Any answers would be greatly appreciated. Thank you.

Brian

You can sex snakes

even that young. Though I am not confident enough to probe tiny, tiny babies I know people who do, or who pop very young snakes. I have never been in a situation that I needed to know the sex of an animal that small...that I didn't trust the person I was dealing with. But it is certainly possible to know. With many colubrids the tail shape tells a lot. Otherwise a proficient prober can tell you.

Apparently the "herp expert" at the pet store does not know how to probe snakes to determine sex.
There is nothing different about the sexual organs when the snake is two years old, other than the fact they are larger.
You can probe to determine the sex as soon as the snake hatches. Normally there is no need for that though, I usually get around to probing them when they are a month old or so and I'm getting ready to offer them for sale.

I sex all my hatchlings after their first sheds by "popping", i.e. manually everting the hemipenes of a male and failing to do so in a female. It is a simple procedure once learned, but you should be shown how by an experienced herper since you may injure the snake if you apply too much pressure. I prefer this method to probing very small/young snakes as even the smallest probes tend to be too large to avoid possible injury or mis-sex males as females if the probe can't go into hemipenes. I will re-sex my female hatchlings several times over a period of a couple of weeks since mistakes have been known to happen if I'm having a "bad" day and am just not doing the procedure 100% correctly.
You should still be able to sex your snake this way since it is still fairly small/young. This procedure isn't the prefered method on older/larger snakes.