Sexing a corn?

Is it true you can visually sex a corn snake without popping? My recent rescue will not let me pop it...and I can't tell what gender.

You can count their tail scales. If you yahoo search 'sexing corn snakes' you'll come across a few pages that show you how it's done. Not always a perfect method, but good for an 'educated guess'.

Like all the scales or just a straight line from cloaca to tip?