[sweetwater]

Yes, age enters into it too, also general health. Dogs can be trained to treadmills, especially a highly tractable and intelligent pup like the A. shepherd. But walking is a good bonding activity. Someday I hope to convince a zoo to provide wolves with a modified (extra wide, and snag-proof) treadmill so they can run themselves happy. Stupid lions get the large enclosures because of their size, while the wolves go catatonic in enclosures often far below their requirements.