Walk your dog long enough and you’ll most likely see it: After peeing or pooping, you’ll see your trusty companion kick up a spray of grass and dirt with their back legs, sometimes in a real frenzy, then trot off.
Some owners find it messy and tug their dog away. But the post-poop kick isn’t a bad habit to break or some quirky backyard dance. It’s a normal behavior, and there’s a real reason behind it.
It’s two signals in one
Dr. Carlo Siracusa, a veterinary behaviorist at the University of Pennsylvania, says that the exaggerated kick is actually a way for a dog to leave a signal, or mark, for other dogs. “It’s a form of communication.”
But this post-pee mark isn’t only about claiming territory. It’s also about presence and timing, a way of saying “I was here.” When a dog sniffs where another dog kicked the dirt or leaves, they can read the (sometimes literal) tea leaves and know how recently or long ago that other dog came by. That’s why dogs keep topping up their marks. A scent that’s a few days old provides different information from one laid down an hour ago.
The kicked up mark carries two different pieces of information. There’s the smell, and there’s the scratching itself, which Siracusa describes as a visual signal on top of the scent. The kicking spreads the odor over a wider patch of ground and pushes some of it into the air, and it leaves a scuffed spot another dog can see.
“If you are around, you can see me,” he says, speaking from the dog’s perspective. “But for those of you that are not yet here, you would smell that I was here.” He compares it to the way a cat marks, with a visible display in the moment and a scent that stays behind.
Courtney Sexton, a postdoctoral researcher at Virginia-Maryland College of Veterinary Medicine, lands on the same two-part explanation, though she notes that she hasn’t studied ground-scratching directly. Excrement and urine are loaded with information, she says, and the kick helps broadcast it.
“If you’re kicking after you go, it’s just going to spread that scent around a larger surface area and increase the likelihood that someone [or, more likely, another dog] passing by is going to catch it.” Some of it drifts into the air, so a dog downwind catches it, too.
The habit goes back to wolves
Sexton traces this behavior to dogs’ wild relatives: wolves. For wolves, territory matters, and scent marks are how a pack signals that this is their turf and warns others to stay away. Other wolves can read stress hormones in a mark or work out what the other animal has been eating.
Studies of free-ranging dogs show that dogs, like wolves, also leave marks to signal where their territory is. In a 2012 study of a free-ranging dog pack, researchers found the dogs used their marks, including ground-scratching, to set up something like a property line and to threaten rivals during fights.
A 2024 study of free-ranging dogs found males were more territorial than females and reacted most strongly to the scent of males from neighboring groups.
Most dogs in the world aren’t household pets, Sexton points out. Many are free ranging, living in loose groups where territory still counts. For a dog asleep on your bed the stakes are lower, but it’s held onto the behavior anyway. Even your domesticated pup often will take the same walking route every day and at the dog park, leaving other dogs pee-mail in kicked up leaves.
For some dogs, it may be about nerves
Siracusa adds a second factor from his clinical work. Anxious dogs, especially in busy environments such as crowded cities, may mark as a way of reasserting themselves. The point, he says, is to get across a simple “I’m around,” so that the dog can avoid difficult encounters with other dogs.
He doesn’t push the idea too far. There’s no data showing anxious dogs ground-scratch more than calm ones, he says, only a broader pattern he sees in the clinic that anxious dogs mark more in general.
Ground-scratching is just one way dogs mark. Others include urine marking and overmarking, where a dog deliberately marks over another dog’s scent.
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No one has studied what’s actually in the scent
Dogs also have scent glands in their feet, so scratching probably lets out some scent from their paws while also spreading the initial mark. But what those glands add to the message hasn’t been studied, according to Siracusa.
“There are glands in the paws,” Siracusa says, but which pheromones they release, and what each one means, hasn’t been worked out.
There is some research pertaining to the paw scent, though. A 2020 study found dogs can tell one dog’s foot gland scent from another’s, though it was unclear whether they can tell the depositor’s sex from it.
When it’s worth paying attention
For owners, when your precious Lassie kicks up the dirt after peeing, it’s usually nothing to fret about. Siracusa says he can’t remember a single client who found it worrying, or even annoying. Not every dog does it, and a dog that does may not do it every time.
What’s worth watching is a change from your own dog’s usual pattern. A dog that always scratches and suddenly stops, or one that starts doing it in a strained, awkward way, could be dealing with pain, rather than sending a message, especially if it comes with other signs like whining during elimination.
“I’m more interested in the change in the normal behavior of a dog,” Siracusa says, “rather than the individual behavior itself.”
For the vast majority of dogs, though, it’s nothing to fix. So, the next time your dog fires grass and dirt across the yard, let them. Just mind where you’re standing.
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