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Caring For Your Mouse, Gerbil, or Hamster

Mouse standing on seeds

Basic Husbandry

General Information

Vital Statistics

  • Body Weight

    • Mice: 20-40g

    • Gerbils: 50-100g

    • Hamsters: 80-150g (some breeds may differ)

  • Life Span

    • Mice: 2 years

    • Gerbils: 3-5 years

    • Hamsters: 1.5-2 years

  • Sexual Maturity

    • Mice: 4-6 weeks

    • Gerbils: 9-12 weeks

    • Hamsters: 6-10 weeks

Behavior and Handling

  • Small rodents jump and wiggle, so they are best supported on the palm of the hand.

  • You may also pick up your small rodent by the loose skin (scruff) of the neck. Be careful with this technique, because small rodents’ eyes can bulge and pop out of the sockets. You can also restrain your rodent with a small cloth.

  • Do not try to hold your small rodent by the tail, as this can cause serious injury.

  • Try to avoid excessive noise, needless excitement, and over handling. Small rodents may bite or show aggression in the face of stress, though they may become tame with frequent, gentle handling. Gerbils tend to be gentle and prefer to run away and hide than to bite.

  • Children handling small rodents should sit on the floor and hold the animal in their lap. Children should only handle rodents under adult supervision.

  • Hair barbering (chewing of the fur) may occur in situations of stress and overcrowding. This may also occur if you pet has lice or mites If this occurs, please contact your veterinarian.

  • Small rodents are usually nocturnal.

Reproductive Information

  • Male rodents have a large scrotum, making them easy to differentiate from female rodents

  • Female rodents frequently fight with other females, and male rodents will likely fight with other males once they reach sexual maturity even if raised together. Females will attack introduced males, except for a few hours during estrus. Occasionally, small rodents will do less fighting if housed together before sexual maturity.

  • Depending on species and size, neutering males may be an option to reduce hormonal drive for aggression and prevent reproduction. However, this surgery may require referral to a specialist.


  • An escape-proof, wire mesh rodent enclosure with a plexi-glass, hard plastic or stainless steel metal solid flooring is preferred for housing.

  • The enclosure should be large enough to accommodate an exercise wheel of appropriate size, nest or burrow area, and feeding area. You can also supply hiding areas such as cardboard boxes; toilet or paper towel rolls and tissue boxes can also be provided for nesting.

  • Bedding should consist of a paper pulp product (like Care fresh or Yesterday’s News), newspaper, or computer paper. Wood shavings may be used but are poorly absorbent (avoid cedar, it’s toxic!).

  • Check bedding or nesting daily to remove any uneaten food. Enclosure should be cleaned weekly to minimize respiratory disease risk.

  • Small rodents can be aggressive towards each other. You may need to separate them if they show signs of aggression towards one another. Syrian hamsters are solitary and should ALWAYS be housed alone. Gerbils are more social and do well in pairs.


  • Lab blocks or rodent blocks should be offered free choice. Recommended brands include Mazuri, ZuPreem and Oxbow Pet Products.

  • Treats may include vegetables, fruit, unsweetened cereal, and hay.

  • Seeds, nuts, and treat sticks are not recommended as part of the diet because they are high in fat and low in protein and calcium.

  • Water should be offered in a sipper bottle or spill proof bowl and should be changed daily.

  • You may clean food and water dishes with mild soap and water or soak them in a dilute (1:30) bleach water solution.

Common Medical Conditions

Conditions Requiring Veterinary Attention

Malocclusion of Incisor teeth

  • This condition occurs when the front (incisor) teeth do not meet properly or are crooked and grow too long for the animal to eat.

  • Small rodent incisors grow continuously and require constant chewing to remain at a proper length. Injuries or age may also cause the teeth to grow abnormally.

  • Regular trimming of the incisor teeth may be necessary so that the animal does not lose weight or suffer injuries to the mouth. This often requires sedation.

Respiratory Infections

  • Symptoms include; sneezing, difficulty breathing, lethargy, and rough coat. The eyes or nose may produce typical crusted discharge or porphyrin, a dark red substance that looks like dried blood (most common in mice).

  • Frequent gasping or open-mouth breathing is a sign of respiratory distress and is a medical emergency.

  • Treatment may include oral antibiotics and in some cases nebulization.

  • Respiratory disease can become a chronic condition, and the rodent may need to be medicated for most of its life.

Tumors and Abscesses

  • Rodents (males and females) are prone to mammary tumors at an early age. These will appear as large bumps under the skin that can grow rapidly. Surgical removal is the only treatment, and the tumors may return.

  • Abscesses are caused by small/deep cuts or bites (especially form other rodents). The skin over the wound heals, and under it, infected abscess material forms a lump. Treatment includes surgically opening and cleaning the abscess and starting the pet on an oral antibiotic.

Common Skin Diseases

  • Lice and mites are very common skin parasites in newly acquired rodents. Mites can also become a problem in geriatric animals. Symptoms include itchy and/or red skin, hair loss over the body, and irritability. Treatments may include injections, topical treatments, or oral meds that kill parasites and are safe for your rodent.

  • Ringworm is a highly contagious fungal infection of the skin that is transmissible to humans. Symptoms include raised, hairless, red patches that are often covered with a light-to-heavy crust. Treatment consists of the applications of topical antifungal medication and often oral antifungal medications.

  • Pododermatitis (“Bumblefoot”) is a pressure sore/swelling that can develop on the bottom of the feet in some rodents. This typically is seen in sedentary animals or older animals living in bedding that is damp or not cleaned thoroughly. Treatment consists of antiseptic soaks, pain medication, antibiotics, occasionally bandaging, and cleaning the environment thoroughly.

Emergency / Critical Care

All emergencies require veterinary assistance. Use the following guidelines to assist you in caring for your pet until you can contact a veterinarian.

Traumatic Injuries

  • Broken Bones

    • Provide your rodent with soft bedding such as a towel or blanket.

    • Minimize handling.

    • Keep your pet in a warm, dark, and quiet area.

    • Keep your pet as calm as possible and contact a veterinarian or local animal emergency clinic immediately.

  • Skin Injuries/Blood loss

    • For any type of injury with blood loss, use direct pressure with a towel or clean gauze to prevent further blood loss. Contact your veterinarian immediately if you are unable to stop the bleeding.

Severe Illnesses and Other Conditions

  • Head Injuries and Head-Tilt

    • Provide your rodent with soft bedding such as a towel or blanket.

    • Minimize handling.

    • Keep your pet in a warm, dark, and quiet area.

    • Keep your pet as calm as possible and contact a veterinarian or local animal emergency clinic immediately.

  • Respiratory Distress

  • If your rodent experiences open-mouth breathing or gasping for air, remove all bedding and minimize handling and stress.

  • Keep your pet as calm as possible and contact a veterinarian or a local animal emergency clinic immediately.

Health Recommendations

Things for your veterinarian to do:

Annual Physical

  • Always have an initial physical exam performed on any newly acquired rodents. During the exam, the doctor will check the teeth, eyes, ears, heart, lungs, and abdomen. The doctor will also check the hair and skin for external parasites.

  • You may have your pet’s fecal sample checked for internal parasites if enough sample is collected.

  • Your pet should have an annual physical done by a veterinarian every year.

Things for you to do:

Overgrown Nails

  • Small rodents may need to have their nails checked/trimmed on a regular basis. If the nails get too long, they can become caught on the cage or toys and break off causing pain and bleeding.

  • If any of the nails break off and begin to bleed, apply styptic powder, flour, or cornstarch to encourage clotting, and apply direct pressure to the nail. If you cannot stop the bleeding, contact a veterinarian.

Over-the-Counter Medication

  • Over-the-counter topical triple antibiotic ointments or any other types of over-the-counter medications are not recommended without first consulting your veterinarian. Productions such as triple antibiotic ointment (for the use of minor skin injuries) can cause digestive problems if ingested and can potentially become toxic over time.