Common Diseases of Small Mammals

Written by Dr. Angie Ahlstrom

Well, we’ve talked about birds and reptiles—time for small mammals! For many people, their first pet was a “pocket pet” such as a gerbil, hamster, rat, or guinea pig. For others, rabbits and chinchillas are great fuzzy friends. These animals offer great companionship, though they present a different set of disease concerns from cats and dogs. Today we will discuss dental disease, respiratory disease, and intestinal disease in rodents and rabbits.

Dental Disease:

Dental disease is very common in small mammals. Rodents have teeth that continue to grow throughout the life of the animal. If the upper and lower teeth are not lined up together properly, these teeth will grow incorrectly and cause serious disease. In some animals, especially chinchillas and rabbits, sharp points can form on the teeth and cause deep ulcers in the animal’s cheeks. Common signs of dental disease in rodents and rabbits include drooling (“slobbers”) from the associated pain, decreased appetite, and dropping food (especially hay). Monitor your pet for these signs of dental disease and bring them to your veterinarian at the first sign of problems.

Dental disease can be prevented by providing proper materials to help wear down the teeth properly. For rats, mice, and gerbils this includes nutritional blocks and untreated wooden toys. For chinchillas, rabbits, and guinea pigs be sure to provide them with free-choice hay; timothy hay is best tolerated by the intestinal tracts of these animals. In addition to providing adequate wear to the teeth, hay also promotes intestinal motility and health.

Respiratory Disease:

Respiratory disease in small mammals is almost exclusively the result of incorrect husbandry. It is important to use only non-irritating bedding. Avoid wood chips such as cedar and pine as these are high in aromatic oils that irritate the respiratory tree; aspen bedding is a better choice. Another option available is CareFresh bedding, which is paper based and non-irritating. Some owners elect to use fleece blankets to line their rodent and rabbit cages. This provides a soft sturdy bedding that can easily be washed.

Bedding should be changed on a regular basis; for many owners, weekly bedding changes work best. Allowing soiled bedding to remain in the cage increases the amount of ammonia in the air (from urine). This ammonia is very irritating to the respiratory tree and can make your rodent or rabbit more at risk of respiratory infections.

Common signs of respiratory infections include sneezing, runny nose and eyes, and porphyrin staining in rodents. Porphyrin is a pigment produced in times of stress and can appear as red tearing or nasal discharge. If you notice these signs, bring your rodent to your veterinarian right away for antibiotic therapy. In some more advanced cases, additional treatment with a nebulizer may be required.

Intestinal Disease:

The most common intestinal problems seen in small rodents and rabbits is due to abrupt diet changes and stress. In rabbits and chinchillas especially, diet change and stress and lead to ileus—a condition where the GI tract stops moving. This leads to cramping and decreased appetite. This decreased appetite further slows the GI tract down, creating a vicious cycle. Prevention of intestinal ileus is key. Be careful not to change your animal’s food abruptly. When switching foods, slowly transition from the old food to the new, mixing a larger amount in each time. This is also true when starting a new bag of hay as there can be small changes between batches of hay that can affect the intestinal tract.


Signs of GI disease include soft feces (not to be confused with cecotropes which are normal digestive products produced by rabbits), decreased appetite, and lethargy. Aggressive treatment is necessary to get the intestinal tract moving normally again. Bring your pet to your veterinarian immediately if they stop eating.


These are just a few of the more common diseases seen in small mammals. For more information about your rabbit or rodent, ask your veterinarian today!

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