Males have much longer tails. I've seen males show concavity as small as five inches, and sometimes not until 7 or 8 inches. It also depends on age. If they are kept too dry, fed poorly, and subjected to improper temperature extremes and incorrect hibernation, they can still be tiny at 20 years old, but still show the secondary sexual characteristics that allow us to sex them.Thanks for the advice! No more back flips!
Is a long tail indicative of male or female? It's a short-tailed species, for sure! At what size does concavity become a sign?