Sheldon, is 5 year old russian tort, roughly 6inches from top carapace near his head to the bottom where his tail is. His mate Shelby, is is the same age but much much bigger, twice his size. I got them together a little over 4 yrs ago as a "pair" .. year after year he shows absolutely no interest in her, none. I've even tried separating them for a significant period of time. I separated them last November and reintroduced them last week. I introduced him into her territory. He's been showing some aggression laying claim over one of the hide outs but lately hasn't wanted her anywhere near him. Opens his mouth as a threat and has even rammed her to get away. None of the aggression I'm seeing is mating related. I'm more educated with Hermanns torts. All my male hermanns have wanted to mate from an extremely young age. Is Sheldon too young? Am I doing something wrong? Any advice is appreciated. Thanks!