Twice a day-once in the morning,once in the evening-Robin will tear through the apartment like a little f-16. He'll jump up on the table,play tirelessly ,climb everything-including me-and tumble for hours in his little felt cube! And there's NO slowing him down! Finally he'll conk out. But last night,he was PANTING with all the exercise he was getting! Is this normal? It seems he either sleeps,or does his Road Runner impression!