Why Does My Rat Brux and Boggle? NZ Guide

The quick answer: rat bruxing is tooth grinding, and boggling is the eye bulging or vibration that can happen with it. In a relaxed rat, it often means contentment, a bit like a cat purr. But rats can also grind their teeth when stressed, anxious or in pain, so context matters.

What bruxing and boggling look like

Bruxing is a soft grinding or chattering of the incisors. Boggling can make the eyes seem to pulse or bulge briefly. It can look startling the first time, but RSPCA describes both as normal rat behaviours when the rat is happy and relaxed.

It is more reassuring when your rat is:

• settled on you or beside a companion
• grooming, exploring or resting normally
• eating and drinking as usual
• bright, curious and moving well
• living with suitable rat company

Use Fancy Rat Care NZ, Small Pets and Exotics NZ, Best Small Pets for Apartments NZ and First Guinea Pig or Rabbit Setup NZ as wider small-pet care context.

Read the whole rat

RSPCA also warns that tooth grinding can be linked with stress, anxiety or pain, so never read bruxing in isolation. A relaxed rat has soft posture and normal routine. A worried or sore rat may be hunched, puffed, hiding, biting, breathing noisily, losing weight or eating less.

Rats are social animals. If you have one rat, review companionship with a rat-savvy rescue, vet or experienced keeper; loneliness and under-stimulation can change behaviour.

When to call a vet

Contact an exotic or small-mammal vet if boggling looks extreme, one eye does not return normally, there is discharge, noisy breathing, not eating, weight loss, head tilt, swelling, wounds, overgrown teeth or sudden behaviour change.

Quick takeaways

• Bruxing is tooth grinding; boggling is eye movement that can come with it.
• In a relaxed rat, it often means contentment.
• Stress or pain can also cause tooth grinding, so read the whole rat.
• Eye changes, breathing signs, not eating or weight loss need a vet.

Related reading

• Fancy Rat Care NZ
• Small Pets and Exotics NZ
• Best Small Pets for Apartments NZ
• First Guinea Pig or Rabbit Setup NZ

References

• RSPCA, Pet rats, checked 2026-06-11: https://www.rspca.org.uk/adviceandwelfare/pets/rodents/rats
• Companion Animals New Zealand, companion animal welfare information, checked 2026-06-11: https://www.companionanimals.nz/

Important notice

*General rat behaviour information for NZ owners. Eye changes, noisy breathing, not eating, weight loss, swelling, wounds or sudden behaviour change needs an exotic or small-mammal vet.*