October 2026
Small rodents pack a lot of personality into a tiny body. Rats in particular are clever, affectionate and quick to learn their names. Because these pets are small and have short lives, health problems can move fast, and a little knowledge goes a long way toward catching trouble early.
Rats are social and do best with at least one same-sex companion, plenty of daily interaction and things to explore. Mice are also social, females especially, and need secure, escape-proof housing. Syrian hamsters are generally solitary and should live alone. They're mostly active at night and may nip if woken suddenly. Gerbils are social, busy burrowers who love deep bedding to dig in.
All of these rodents have front teeth that grow continuously, so they need safe things to chew.
Choose a roomy, well-ventilated enclosure that's easy to clean, with solid flooring or at least solid areas to rest on to protect the feet. Use dust-free paper bedding rather than cedar or pine shavings, which can irritate the airways. Add hiding spots, nesting material, chew toys and a solid exercise wheel of the right size, and keep the enclosure in a cool, quiet spot away from direct sun and drafts. Most small rodents don't handle heat well.
Clean the enclosure regularly. Ammonia from urine builds up quickly and is hard on small lungs.
Rodents are prey animals, and many stop showing pain the moment a person walks into the room. At home, the clues are usually changes in everyday behavior: a messier, poorly built nest, less burrowing, climbing or rearing up, less grooming or a scruffy coat, a hunched posture, pulling away from cage mates, or in rats and mice, more red-brown staining around the eyes and nose. A short video taken when your pet doesn't know you're watching can tell me a lot.
Respiratory disease is one of the most common problems in pet rats. It's often linked to bacteria many rats carry, and made worse by ammonia, dusty bedding and stress. Watch for sneezing, sniffling, noisy or effortful breathing, red-brown discharge around the eyes or nose (a pigment, not blood), weight loss and reduced activity.
Lumps and tumors are common, especially mammary tumors in female rats. These are usually benign but can grow large. Mice and hamsters can develop lumps too. Any new lump deserves a check, because early removal is usually simpler, and spaying young female rats greatly reduces the risk of mammary tumors.
Kidney changes are common in older rats. For seniors, and before long-term medication or anesthesia, I often recommend bloodwork and a urine test.
Dental problems show up as drooling, dropping food, weight loss or front teeth that look too long or crooked. Skin problems from mites and lice cause itching, scabs and hair loss, and over-grooming from stress or cage mates can look similar. Digestive upsets can be serious in hamsters in particular, and diarrhea or a wet, dirty tail area needs prompt attention.
Feed a quality lab block or pellet made for the species, with small amounts of fresh vegetables, and go easy on sugary treats and seed mixes. Keep housing clean, dry and well ventilated. Handle your pets gently every day and feel for lumps as you go. Weigh them regularly on a gram scale, and schedule a yearly wellness exam.
Rodents can carry germs that affect people, including the bacteria that cause rat-bite fever. Wash your hands after handling pets or cleaning cages, and see your doctor if you feel unwell after a bite.
Call the same day if your rodent is breathing hard, wheezing or clicking, has stopped eating, has diarrhea or a wet tail area, or has a head tilt, is circling or seems weak. If your pet hasn't eaten since yesterday, call rather than waiting for a routine appointment.
Book a prompt visit for a new or growing lump, weight loss, itching, fur loss or scabs.
Dr. Logan Kopp, Nashville's exotic companion mammal specialist, sees rats, mice, hamsters, gerbils and other small rodents for wellness care, respiratory disease, dental problems and lump removal at Priest Lake Veterinary Hospital. Call (615) 361-4646.
This article is general information, not medical advice for your pet. Reading it doesn't create a veterinarian-client-patient relationship (VCPR). Please talk with your own veterinarian before making changes to your pet's care.