Woman scratching dog's belly

Have you ever noticed that when you scratch your dog’s belly, something unusual occurs? It happens every time you hit the “sweet spot.” You know the one. Suddenly, your dog starts kicking his back leg like he’s running on his side. 

Dogs are full of quirky habits, but this one is puzzling. What is it about that sweet spot that makes a dog’s leg twitch or kick? Are they ticklish or is it something else?

Oakland Veterinary Referral Services takes a look at this funny mystery of why dogs kick when you scratch their belly.

The Scratch Reflex Redux

What happy dog doesn’t love a good belly rub? Most pet owners will agree that their pets love being scratched. They all have their favorite spots. For most, the belly is a favorite – from the smallest to the largest dogs, it’s true. And what happens when you scratch…sometimes your dog’s back leg starts to shake or kick. These kicks, caused by the belly scratch, look like a running or swimming motion. 

Strange, huh?

Well, it isn’t so mysterious. We call this response the scratch reflex. It’s an involuntary response, much like the one that occurs when the doctor taps below your knee (the “knee-jerk” reflex). Our reflexive kicks are similar to our dogs’ kicks. 

Nerves under the skin connected to the spinal cord relay a message to your dog’s leg to kick without it having to pass through the brain.

When your pet kicks in response to a scratch, it looks pretty funny to us, right? Is it funny for our pets too? Not so much. It actually startles your pet. Like a bug landing on their nose. That’s probably why your dog looks just as puzzled by their own behavior. It’s the same type of reflex that occurs when your cat lifts its butt high when you scratch the tail’s base.

What’s even cooler about this reflex is that it can help your veterinarian uncover potential problems. By activating this reflex, your vet can determine if there is nerve damage or neurological damage occurring in certain areas. 

Other examples of involuntary reflexes that we’re familiar with:

  • Blinking when something is near the eye
  • A sudden movement in response to surprise or pain

Putting It All Together

Does your dog kick when you scratch their belly? Should you stop? If your dog enjoys a good belly rub, continue to reward them that way. There’s no need to deny your pet the attention or deny yourself the joy of seeing your pet’s enjoyment of a belly scratch. The interaction is good for them and you!

If you have any questions about your dog, our friendly and knowledgeable team is here! Please give us a call.