I don't know what the vet we go to looks for but when we had a nacropsy done he told us that she was aproximately 8 years old. I think he told us by looking at the tissue he could guesstamate her age. The snake past away due to toxic shock from a bad feeder. It took her months for the snake to pass after the bad feeder but she didn't eat regularly after that. The vet said that is what probably let her survive as long as she did. But that is the only way i know to get a snakes age. Btw she was a wc female so knowing her age was almost impossible.