Hi there the 40gl breeder is the smallest size I use for some of my adults. Ideally I have them in 4x2x2 enclosures that I build out of plywood. The size of the cage will not stop him from the behavior that you are witnessing. As you stated he recently came out of brumation and he is now in the "mating mood" and wanting to find a nice female to knock up.. All my males do this at this time of year as it is natural for them. You might try looking into reptile basics as they sell cages and I believe shipping is included not sure about Alaska but worth a shot. Rich is a great guy and he might be able to help you out if you didn't want to try to make one yourself..