It does not surprise me that some dogs actually injure themselves from wagging their tail too hard. During my days working at a boarding kennel, a few dogs did this. A great dane named Simon actually came in with a pre-wrapped tail every time, just to prevent him from hurting his tail in advance.

We called it happy tail. What happens is the dog wags and wags his tail hard enough to cut it open.

When my mutt is happy, he shakes his whole body, dances and hits his tail against the wall like he’s playing drums.

All I have to do is look at Ace and his tail will wag. My friends joke that I have Ace just to feel good about myself. But they’re partly right, it is nice to have someone basically worship me. Any retriever owner probably knows what I’m talking about. But isn’t that part of the reason we love dogs?

The worst case of happy tail I ever saw was a yellow lab named Sunny. Sunny was a typical lab, full of energy and craving attention. All you had to do was be in the same room as Sunny and her tail would go 90 miles an hour.

Well, one afternoon, I noticed blood splashing from Sunny. Drops of blood sprayed from her and onto the dogs near her. Her blond coat was turning red. When I went in her cage to take a look, her tail just wagged harder. I had to grab hold of her tail, just to help keep it still. By that time, I was covered in blood, too. 

Sunny’s tail was actually sliced to the bone, the way a snapped pencil looks when the two halves are held together by a splinter. And still, she continued to try and wag it, oblivious to any pain. At the vet’s office, she was happy as ever. The doctor took one look at Sunny and said her tail would have to be amputated. And then he added, “I do this at least once a month.”

Poor Sunny. She was just fine, but after that she only had half a tail to wag.