As most of you know, our older GSD Jax and our younger one, Kane are closely related. They share a sire and their dams are full sisters. Jax is highly intelligent and eager to please. Kane is intelligent too (I think, but I'm partial), but couldn't care less about performing a command or trick to please. Jax is high energy all the time. Kane is a couch potato. Jax needs interaction to be happy. Kane is just a happy-go-lucky boy. So we bought Jax a puzzle toy for Christmas. This: Jax was very quick to figure it out and how to "beat the system". Kane wanted the treats that it held, but wasn't willing to work for them. Kane liked the ball we got him for Christmas, but only played with it for a few minutes. He likes to carry it around in his mouth, prancing, but isn't interested in the squeaky sounds it makes. He just carries it around. I know Kane has intelligence, even if his talents are different from Jax's. Kane knows how to open doors, open the fridge, and knows how to work the foot petal on the kitchen trash can; things Jax hasn't accomplished. I just can't figure out why Kane isn't interested in interacting - Kane's idea of interacting is for someone to give him a belly rub and doesn't have the work drive that Jax does. Could it be the age difference? Jax is 2 yrs. 9 months old; Kane just turned two this month. Or Could it be that we've had Kane since he was a little more than 8 weeks old. Jax was a bit older, only coming to us after his first owner decided he didn't want him (and kept him in an outdoor kennel from the start).