I have this problem with wolves, happening within SinglePlayer.
What happens is, I friend the wolf with between 1-5 bones. Simple right?
Then, I log out of MC, and come back a couple days later. I go to my wolf, who I last left sitting in place. Right clicking does nothing. I can't get him to get up, he won't respond. I tried drowning him and running away, in hopes he would "teleport" to me, but he just stands there and drowns. Fine. I kill him in the end.
Is this a glitch? I've never heard reports like these.