How do you determine the sex of a Red-tail Boa snake?

There are three ways to sex a snake. You can pop, probe, or "feel". Popping is when you turn their internal sexual organs inside out, which is designed more for fat-tailed snakes such as ball pythons. Probing is when a lubricated probe is inserted into the cloaca, and the depth it is inserted determines the sex. This should only be done by experienced handlers. You can also "feel" the snake to determine the sex. By running your finger along its tail from the vent to about halfway down the tail, you can determine if it's male or female. If you feel a "pop" kind of like a rubber band snapping, then you have a male, if not, then a female. Hope this helps!