Tegu's will hibernate if and when they want to, there's not much you can do about it. Some of Varnyard's Tegu will go into hibernation in August when it's still in the 80's. Hibernation isn't necessary for them to reproduce. As far as I know, our Blue's have never hibernated. Last year we had a successful hatching and I expect another clutch in 16 days. Our male Red does hibernate for 2 to 3 months in a 75 degree room.