Hamsters, chinchillas, degus, gerbils, and rats make up 10-15% of the exotic species we see in a veterinary exotic pet practice. These furry pets are rodents and are not loved by everyone. The word rodent means, “to gnaw”. Rodents are the most populous mammalian order. Many municipalities have quite an extensive budget to eradicate wild rodents because they are considered pests. Rats have a pretty bad reputation, as they can be outdoor pests at times in neighbourhoods where food or trash is left out, water sources are nearby
Rats and are highly intelligent animals with an average lifespan of 18-24 months. They are highly intelligent and can live on almost any type of human food or rat pellets because they are omnivorous. Rodents should be housed in a roomy cage with plenty of air flow. A wire cage with a plastic bottom is ideal because it provides more ventilation than a glass enclosure, and this helps in the prevention of Mycoplasma lung infection. Enrichment devices include a running wheel for exercise, pieces of pipe or a plastic rodent “Igloo” for security, and sheets of paper or cardboard to tear up for nesting. Out-of-cage time in a rat-proofed room or in large-size exercise ball provides exercise. Escaped rats often return to their cages. The bedding may be an absorbent fiber bedding such as recycled paper products, compressed wheat straw, citrus litter, corn cob or possibly aspen shavings. Pine or cedar shavings emit volatile oils that tend to cause allergy and skin rash. Bedding should be changed every 3-4 days to prevent fecal and urine buildup. Fresh water should be available at all times usually from a sipper as water bowls are easily tipped. The sipper needs to be checked daily to make sure it is flowing properly.
Diet is arguably the most important aspect of small herbivore/omnivore husbandry. It is useful to group pet rodents based upon their dietary requirements because similar patterns emerge with regards to disease. Degus have a functioning cecum, like the chinchilla and guinea pig do, and require a high-fiber diet. A cecum ferments hay and produces lots of good bacteria that help digest the food and maintain gut health and motility. Hamsters, mice, rats, and gerbils have a simple digestive tract and require a diet higher in energy. All rodents have hypsodont (“open-rooted”) incisors that continue to erupt throughout life. However, degus also have hypsodont cheek teeth.
Rats feed primarily at night. Diet should be commercial rodent block. Fresh fruits and vegetables are provided in moderation. Only limited amounts seeds, raisins, etc. should be provided as treats. Rats live longer if fat and protein are somewhat restricted. Seed diets should be avoided because they allow animals to select very palatable seeds such as sunflower seeds. More uniform nutrition can be provided with the use of formulated diets (blocks or pellets).
All rodents perform coprophagy to some degree, which provides B vitamins, optimizes protein utilization, and repopulates beneficial gastrointestinal microorganisms.
New Rodent Pets
Newly obtained rodents should be quarantined for 30 days or more before mixing with established individuals. A veterinary examination and fecal testing are recommended during this period. Rodents of different species should not be mixed because one species can carry organisms that are pathogenic to another. Use caution when introducing individuals of the same species as many rodents show aggression toward new arrivals. If the animal is to be cared for by a child, then an adult should regularly check for on the pet’s status to see that the rodent is well and the cage is in order.
Rodents are prone to heat stress. They do not sweat and are unable to pant. The tail and ears are largely responsible for their limited ability to dissipate heat. Mice and some other rodents hypersalivate in response to heat.
Located behind the eyeball of rodents is the Harderian gland, which produces porphyrin-rich secretions that impart a red tinge to the tears. Normally, the lachrymal secretions are spread over the pelage during daily grooming. However, during stress or disease, these may accumulate around the eyes and or nose and may be inaccurately diagnosed as blood.
Rats are generally disease resistant, however, respiratory infections are common (Mycoplasma). Other conditions include dental malocclusion, head tilt, obesity, chronic renal disease, salivary gland inflammation, and ectoparasites (mites and lice). Mammary gland tumors occur in a high percentage of females.
Common Rodent Care Mistakes
- Dirty or wet bedding, excessive ammonia, unsanitary environment
- Water runs out, sipper tube malfunctions
- Abrupt diet change (e.g., running out of regular food and feeding a substitute)
- Inappropriate treats leading to diarrhea and other digestive symptoms
- Inappropriate social structure leading to aggression or stress
- Adding new animals to a collection without a quarantine period or veterinary exam
- Allowing contact between different rodent species
- Waiting too long to see a vet, worsens patient prognosis
Geriatric Rodent Care
When our pets get older it is important to evaluate their quality of life as they age and give them proper support, as they require it. Every patient deserves this consideration.
The “HHHHHMM” stands for Hurt, Hunger, Hydration, Hygiene, Happiness, Mobility, and More good days than bad. Adequate pain control is ranked first. In addition to obvious types of pain, the ability to breathe properly should be assessed. In humans, dyspnea ranked at the top of the pain scale. Along with the pain, dyspnea can lead to anxiety and panic as well. It also takes a lot of energy to work at breathing.
Assessing each of these aspects of life that comprise a good health status is useful for pet owners when evaluating the care the pet needs at the end of life.
Can the pet eat and drink? Maintain its coat and urinate defecate normally? If arthritis is impeding movement or there is any pain then a pain medication is indicated. Is the pet happy and enjoying interactions and mental stimulation? As the owner, you will be able to tell.