Males will have one or two enlarged suckers near the arm base. They will be roughly 1.5 times the diameter of the closest suckers and may be on the front four arms. The number of arms containing the enlarged suckers seems to vary and my one male had obvious enlargements on all eight arms. From the few we have seen reported, the age of sexual maturity seems to vary and the suckers are not obvious until they are sexually mature. Additionally, a mature male will carry his third right arm (clockwise) curled almost all the time and will rarely use it.
My observations suggested that the females tended to stay in a very limited number of dens and remained in the dens most of the time where my males changed dens every couple of days. However, Greg did not see a corresponding behavior with Beluga and my wild caught female did not remain in one place until she started brooding so, at this point, I don't believe there is much to go on behavioraly.