Here’s a video that’s been going around the Net lately. It’s titled–for reasons that will become obvious if they aren’t already–"Don’t touch my bone."
It’s funny!
A lot of folks have been wondering what’s going on in the mind of the dog in the video. At first glance, his behavior certainly seems strange, and hypothetically he could have a canine equivalent of one of those disorders where a part of a person’s body (e.g., a hand) moves without voluntary control.
But I think there may be a very simple explanation:
<SPOILER SWIPE>He’s just playing! Dogs sometimes chase their tails, seeming to treat a body part (their tail) as if it were part of another critter. Something like that may be happening here. This dog may have achieved the level of abstraction needed to play a little game of defending his bone against an imaginary aggressor, while using his foot to play the part of the imaginary aggressor. It may just be a dog version of what happens when little boy put toy soldiers or toy robots or whatever in each hand and then let the toys "fight" in front of them. If so, the dog isn’t crazy. He’s just smart and playful.</SPOILER SWIPE>

