Rodents Don’t Gnaw Just to Trim Their Teeth—It Also Feels Good, According to a New Study

The findings could help humans who grind their teeth or clench their jaws

Sara Hashemi | Daily Correspondent

March 19, 2026

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Beavers are famous for nibbling away at trees, and their sometimes-peskier cousins, rats and mice, might chomp on drywall and electrical wiring in your house. While rodents generally gnaw to help file down their constantly growing front teeth, researchers have just uncovered another reason for the behavior: It feels good.

The findings, published in the journal Neuron on March 10, could explain why dogs love to chew on bones, and why some humans can’t stop biting their nails or grinding their teeth.

“Gnawing itself may be rewarding,” says Malavika Murugan, a neuroscientist at Emory University who was not involved in the study, to Jake Buehler at Science. “In hindsight, this actually makes ecological sense, given that rodents depend heavily on their [front teeth] to interact with the environment.”

Scientists have long thought that mechanical considerations drove the animals to passively gnaw on hard materials, says study co-author Bo Duan, a sensory neuroscientist at the University of Michigan, in a statement. If rodents don’t trim their ever-lengthening front teeth, called incisors, their jaws will become misaligned, making it hard to eat.

But Duan and his colleagues noticed that some of the mice in their lab were neglecting teeth maintenance. “That observation suggested to us that something beyond a simple reflex might be involved,” he says in the statement.

So, the researchers examined how gnawing affects the brains of mice. They used animals that were genetically modified so a toxin would kill certain cells in the brain area responsible for coordinating facial movement. Injecting the toxin revealed that touch-sensitive nerve cells near the teeth send signals along a path that travels to part of the brain’s reward and motivation system. Disrupting the circuit stopped the mice from gnawing, resulting in jaw misalignment, while activation of it triggered the release of dopamine, known as the “feel good” chemical messenger.

“If you block the motivation pathway, the sensory-motor pathway is still intact, and that does help maintain teeth,” Duan says in the statement. “But, without the motivation, it’s just not very efficient. So, the motivation part is very important.”

The findings could help people who struggle with teeth grinding and jaw misalignment, since the same neural mechanisms observed in rodents may also play a role in humans and other animals.

“Why do we chew bubble gum? Why does a dog chew on a bone?” study co-author Joshua Emrick, an oral and craniofacial biologist at the University of Michigan, tells Science.

For instance, individuals with conditions that alter motivation and behavior, such as autism and depression, have jaw misalignment more often than people without those conditions, according to past research. And Parkinson’s disease patients given treatments involving dopamine precursors can develop teeth grinding and clenching problems, Emrick says in the statement.

“Now we have the evidence for a biological circuitry link that may be contributing,” he adds.

Sara Hashemi | Read More

Sara Hashemi is a science writer and fact-checker currently based in New York City. Her work has appeared in Sierra, The Body, Maisonneuve magazine and more.