You’ve surely seen your dog do some strange things in his days, including thumping his leg against the ground or shaking it violently during a petting session. While the behavior may seem odd to you, he’s just doing what feels natural to him to get some relief or fine tune his hunting skills.
Most dogs have that sweet spot on their bodies -- the one that makes their legs go crazy. Usually scratching the “saddle region” -- along his back, sides and belly -- is most likely to get this kind of reaction. While you’re rubbing away, he’ll thump, shake or twitch one or more of his legs. He can’t control it; rather, his brain automatically sends messages down to his paws to shake away whatever is tickling his skin. This impulse is known as the scratch reflex.
If you’ve ever felt a fly land on you or slapped your leg after that annoying mosquito goes in for a bite, you’re just following your impulse to get some relief. The same theory applies to canines. Maybe Rascal is perfectly relaxed, but he feels some kind of varmint crawling around on his leg. Rather than sitting up and scratching, his leg instinctively twitches or shakes to remove the pest and get some relief. In the worst case scenario, he actually has to get up from his snooze and thump his leg against the ground to knock that bug off.
Going for the Kill
Your family fur ball has the genes of an established hunter. Sure, you fill his dish every night so he doesn’t have to go forage for food, but his brain still makes him want to hunt. If you see him thumping his leg on something, possibly a toy or a bug, he’s giving his “prey” some life, making him feel like he’s really getting the hunt. He may even finish the job and ensure his kill is really dead by shaking it in his mouth, flicking it up in the air and then bringing it over to you to see.
While thumping of the legs is typically just a quirk that dogs do, once in a while it could be a sign of a problem. He could have an allergy that makes his skin itchy -- that incessant shaking gets rid of an itch that he can’t scratch. Or if his joints are stiff and bothering him, he may try to loosen up his legs by shaking them loose. It’s also possible that he has a wound, splinter or broken nail that is aggravating him, causing him to shake off the problem. Talk about the behavior with your vet, just to be on the safe side.