Females tend to have more round bottoms, whereas males have pointer bottoms or "tails" (almost like a bone protruding). Coloration on the chest (yellow/orange) is not that reliable as both males and females have it. After about a year to a year 1/2, if it is a male, he will lose his stripe down the back. Females will retain this stripe. Males also tend to have more round snouts, and females have pointy snouts. I hope this helps!