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Mus musculus

Mice are social, alert and extremely active small animals.


Mice Facts

Average Adult Size 3 inches long
Average Life Span up to 3 years with proper care
Diet omnivore


A well-balanced mouse diet consists of:

  • High-quality mouse food or lab blocks and limited amounts of grain, vegetables and fruits.
  • Clean, fresh, filtered, chlorine-free water, changed daily.
  • Do not feed chocolate, caffeine or alcohol as these can cause serious medical conditions. Avoid sugar and high fat treats.


Things to remember when feeding your mouse:

  • Fresh food and water should always be available.
  • A limited amount of grain, vegetables, fruits or Timothy hay can be given daily but should not exceed 10% of their total diet
  • Vegetables and fruits not eaten within 24 hours should be discarded.


  • Mice acclimate well to average household temperatures, not to exceed 80°F; be cautious of extreme temperature changes. The habitat should never be in direct sunlight or in a drafty area.
  • Habitat should be plastic, metal or glass and escape-proof with a solid bottom; there should be plenty of room for the mouse to exercise and play. It is best to provide the largest habitat possible.
  • 1-2" of bedding should be placed in the habitat; proper bedding includes high quality paper bedding, crumbled paper bedding, or hardwood shavings. Cedar-based products are not recommended.
  • Mice can be kept in same-sex pairs that have been raised together. Different types of small animals should not be housed together.

Normal Behavior

  • Play during the night and rest during the day (nocturnal) but can adjust to your schedule.
  • Very curious, like to burrow, hide in objects and play; easily frightened by loud noises.
  • Chew on objects to maintain incisor teeth, which grow continuously; ensure they have plenty of wood chew sticks or mineral chews.

Habitat Maintenance

  • Clean and disinfect the habitat and its contents at least once a week with a 3% bleach solution. Rinse and allow to dry completely before placing the mouse back into the habitat.
  • Remove wet spots daily; change bedding at least once a week, or more often as necessary.

Grooming & Hygiene

  • Mice stay clean and rarely need baths (males have a stronger odor than females), but can be spot-cleaned with a damp washcloth or unscented baby wipes if needed.
  • It is normal for a mouse's teeth to be yellow; cleaning is not necessary.
  • Consult with a veterinarian if a mouse's teeth seem too long.


Signs of a Healthy Animal

  • Active, alert, and sociable
  • Eats and drinks regularly
  • Healthy fur and clear eyes
  • Breathing is unlabored
  • Walks normally

Red Flags

  • weight loss
  • abnormal hair loss
  • diarrhea or dirty bottom
  • distressed breathing
  • lethargic
  • eye or nasal discharge
  • skin lesions
  • overgrown teeth

Common Health Issues

Health Issue Symptoms or Causes Suggested Action
Health Issue Diarrhea Symptoms or Causes Loose stool caused by poor diet, stress, internal parasites, unclean housing, or other illness. Suggested Action Consult with a veterinarian to determine cause and treatment.
Health Issue Malocclusion Symptoms or Causes Overgrown teeth. Suggested Action Consult with a veterinarian to have teeth trimmed regularly.
Health Issue Mites Symptoms or Causes External parasites that cause mice to lose patches of hair. Suggested Action Consult a veterinarian for treatment.
Health Issue Tumors Symptoms or Causes Abnormal lumps. Suggested Action Consult a veterinarian.


Ask a store partner about Petco's selection of books on mice and the variety of private brand products available for the care and happiness of your new pet. All private brand products carry a 100% money-back guarantee.

Because all small animals are potential carriers of infectious diseases, such as Lymphocytic Choriomeningitis, Rat Bite Fever and Salmonella, always wash your hands before and after handling your small animal or habitat contents to help prevent the potential spread of disease.

Pregnant women, children under the age of 5, senior citizens and people with weakened immune systems should contact their physician before purchasing or caring for small animals and should consider not having a small animal as a pet.

Go to the Centers for Disease Control at for more information about small animals and disease.

Note: The information in this Care Sheet is not a substitute for veterinary care. If you need additional information, please refer to the sources on the following page or contact your veterinarian as appropriate.

Developed with and approved by a qualified veterinarian.