I know there are aquite a few sites....will have to get the links again, but didn't want you waiting so long at least for an answser. The difference between the males and females of this type is the males usually have a dark brown line on his belly starting from the mouth to the tail, often faded but very prominant when he is "in the mood". The females lack this strip and just have white bellies. I will have to get those links to you in a bit......hope this helps for at least the time being.