Actually, from a visual standpoint, females tails are thicker and shorter. Males tails are longer and thinner. Males have larger and more hook shaped spurs. Females have slightly smaller, thinner spurs which do not hook inward as drastically. These are not 100% accurate ways of telling sex but if anyone here who has multiple BPs that are a year or older will look and compare them all, they would see these differences are quite common. Older BPs are very good at holding it in. If its a male I mean. You need to use much more pressure and more of a kneading motion to get any hemipenes to come out. This is the most common reason an older BP would be mis-sexed by popping. I prefer to probe. No guessing then. No squeezing the begezus out of your poor snakes rear end either