Why does a mouse grind its teeth? - briefly
Mice grind their incisors when they are stressed, sick, or have dental discomfort. The action also serves to file down teeth that grow continuously.
Why does a mouse grind its teeth? - in detail
Mice grind their incisors as a physiological necessity. Continuous eruption of the front teeth requires constant abrasion to keep a functional length. Without regular wear, the teeth would overgrow, impair feeding and cause injury.
The grinding behavior also serves several adaptive functions:
- Thermoregulation – rapid jaw movements generate heat, helping the animal maintain body temperature in cold environments.
- Stress response – elevated cortisol levels trigger repetitive chewing, which reduces tension and provides a coping mechanism during predator exposure or confinement.
- Communication – audible gnashing can signal dominance or territorial claims to conspecifics, especially in dense nesting sites.
- Dental health maintenance – the action removes enamel plaques and prevents the formation of sharp points that could damage oral tissues.
- Nutrient acquisition – grinding facilitates the breakdown of fibrous food, enhancing mastication efficiency and digestion.
Neurobiological control involves the trigeminal nucleus, which coordinates mandibular muscles. Sensory feedback from periodontal ligaments informs the brain about tooth contact pressure, adjusting the grinding intensity. Hormonal influences, such as thyroid hormones, modulate tooth growth rate, indirectly affecting the frequency of abrasion.
Environmental factors modify the pattern. Soft bedding or abundant chewable materials reduce the need for excessive grinding, while barren cages increase the behavior. Temperature fluctuations above 20 °C diminish thermogenic grinding, whereas temperatures below 10 °C amplify it.
Pathological conditions may alter the normal rhythm. Dental malocclusion, infection, or neurological disorders can produce irregular or excessive gnashing, often accompanied by weight loss or behavioral changes. Monitoring the frequency and intensity of this activity provides a non‑invasive indicator of overall health in laboratory and pet mice.