Why Do Dogs Kick When Scratched

Your dog comes up to you and rolls over to invite a good belly scratching. You oblige, and their leg starts to twitch. A moment later, they start to kick as if they themselves were the one scratching that magic spot on their belly. They may even end up kicking your hand away or scratching you in their excitement or overzealousness. Some dogs kick with both back legs at the same time, or even kick while standing up. Why do dogs kick like crazy when they’re being scratched? Is it a magic spot, or just something all dogs like doing?

All dogs love attention, in any way they can get it—petted, scratched, or snuggled, it really doesn’t matter. So what is it that makes your dog kick like a budding karate enthusiast when you find that one magic spot?
It’s actually a reflex—something your dog can’t do anything about. Humans have automatic reflexes too, like when your doctor whacks your kneecap to test that reflex to kick. Newborn babies have many reflexes, like the reflex to suck or grab. Dogs have reflexes too. For a dog, that magic spot initiates a scratch reflex. It’s actually caused by a network of nerves under your dog’s skin, which sends messages to the spinal cord. Those messages instruct your dog’s leg to start kicking. Your scratching makes your dog subconsciously think that your fingers are an itch or a pest they need to scratch.
It’s actually kind of a survival instinct. Since dogs may acquire fleas, ticks, or other critters, that instinct exists to try to rid them of what may be a dangerous parasite, since many bugs carry diseases. It’s a little like a human’s reflex to put their hands out when falling: your body reacts before you’re consciously aware of the danger. Veterinarians may use a dog’s scratch reflex to test for certain neurological conditions.
So if your scratch creates the reaction that there may be a bug on them, does your scratching bother your dog? Not likely. As long as your dog isn’t showing any other signs of distress or discomfort, they’re probably just enjoying a good scratching. Besides, if your dog hated it, they probably wouldn’t keep rolling over and offering their belly. Some dogs may appreciate a good belly scratch more than others. If your dog rolls over and offers, odds are they’re totally good with a thorough scratching.

If your dog kicks when you’re giving them a good scratch, there’s really nothing wrong with it. They might accidentally kick your hands or scratch you, but it’s not their fault, any more than it’s your fault for sneezing or hiccupping. It’s automatic and biological.
Some dogs, especially if they have allergies or sensitive skin, may be more inclined to start kicking away than others. Be cautious of their skin, and don’t scratch too much if it’s already irritated. Some breeds, especially those with super short hair, like Pitt Bulls, may have more prevalent skin issues than other breeds. A healthy diet and proper hygiene, including using the right kind of soap and not bathing too much, can help with their skin problems. Snacks or diets that include salmon or other good fats may also help.
Not all dogs automatically enjoy having that itch scratched. Pay attention to your dog’s body language. If their ears are back, their mouth is closed, and their muscles tense, there’s a chance they’re not actually enjoying being scratched.
If that kicking is like a reflex, they can’t actually help it. It might be comparable to being tickled. It might be fun for a moment, but it quickly can become almost painful. Consider your dog’s body language before going to town on their magic itchy spot.

Every dog has the same system of nerves in their skin. Some dogs have a more intense reaction to being scratched than others. Some may kick feebly with one foot, almost a twitch rather than a kick. Other dogs may kick with both legs, hard. Those that are already itchy, like dogs with allergies, may be more inclined to kick. It’s a good idea to pay attention to your dog’s skin, which should be clear and smooth. Redness, dryness, or rash can be indicators that your dog has sensitive skin or allergies. Talk to your vet to find out what kinds of dietary or hygiene changes you can make to help alleviate their skin problems. Pay attention to your dog’s body language to see whether they’re enjoying your attention or not. A dog that keeps rolling over and is panting or “smiling,” is probably enjoying it. But not every dog will. 

So, just because your dog kicks up a storm when you scratch their ribs, it doesn’t mean they’re enjoying themselves. Pay attention to your dog’s body language to determine whether or not they want you to scratch away. If they seem content, go ahead. Any affection you give them is a good thing, even the itching, kicking kind.