Do Pet Rats Attract Other Rodents? Debunking Myths

The University of California's rat guide names food, water, shelter, and gaps into a building as the things that draw wild rats to a house. A pet rat is not on that list, but its food is. What a pet parent controls is the food that gets left out, how the food is stored, and whether the cage is secure.

This page covers what does bring wild rats and mice close, how pet rats and wild rats are related, what the research says about rats defending a home cage, and the feeding and cleaning habits that keep a rat household from becoming a feeding spot for other animals. Pet rat care basics are in a separate guide.

What Brings Wild Rats and Mice Close

The UC Statewide Integrated Pest Management Program says rats live and thrive near people and gives three things to limit: food, water, and shelter. Of the foods wild Norway rats prefer, it lists cereal grains, meats, fish, nuts, and some fruits, and it adds that they accept whatever food is plentiful, such as food waste around untidy properties.

The same guide says nightly foraging ranges for Norway rats run anywhere from 100 to 500 feet from the nest, and that when food and a nest are close together, rats usually stay as close to the nest as they can. Its list of signs of a rat problem starts with droppings around dog or cat dishes or pet food storage containers.

Entry points matter as much as food. UC IPM says to seal cracks and openings larger than 1/4 inch, and it says rats can chew through plastic, foam, wood, and caulk. Young rats can squeeze under a door with a gap of only 1/2 inch.

How Pet Rats and Wild Rats Are Related

The RSPCA says domestic rats are descended from the brown rat, the same animal the UC guide calls the Norway rat, and that their biology and behavior are very similar to their wild cousins. Pet rats live longer than wild ones, according to the RSPCA, because they have more access to food, water, and veterinary care and are safe from predators.

Rats are social animals, and the RSPCA says they use their sense of smell to recognize other rats. They also communicate with ultrasonic calls. A review of rat research in the journal Current Neuropharmacology describes how rats emit ultrasonic vocalizations of three kinds: pups call at 40 kHz when separated from their mother, young and adult rats use 22 kHz calls in stressful or threatening situations, and 50 kHz calls come in pleasurable situations.

A separate study by the Bernstein Center in Berlin recorded rats' ultrasonic squeaks during tickling play, and our page on rats and tickling covers it.

Do Pet Rats Defend Their Cage

A 1994 study at Wesleyan University in the journal Physiology and Behavior looked at territorial fighting in laboratory rats. The researchers put an unfamiliar rat into the home cage of a male and female pair, and the pair fought it. The territorial fighting was strongest against intruders of the same sex. The study used rats only and did not test wild mice or wild rats.

The same paper describes a second kind of fighting, competitive fighting, which it set off in pairs of hungry cagemates by dropping one food pellet into their food hopper. The authors report that food deprivation raised competitive fighting and lowered territorial fighting. The RSPCA advises giving a group of rats multiple food objects rather than just one, which helps avoid competition.

Why Wild Rodent Contact Is a Health Problem

UC IPM says rats can carry and transmit diseases to people, pets, and livestock, and the most common are typhus, leptospirosis, foodborne illnesses caused by germs such as salmonella, E. coli, and campylobacter, and rat bite fever.

The CDC says rat-bite fever is an infectious disease people can get from contact with rodents. It says the rodents that carry it include rats, mice, gerbils, guinea pigs, and squirrels, and that it can spread to people through scratches, bites, or contact with a rodent's saliva or pee. The CDC's small mammal page adds that small mammals can sometimes carry germs that make people sick even when they look clean and healthy.

The CDC small mammal page lists these diseases: Campylobacter infection, Giardia infection, leptospirosis, lymphocytic choriomeningitis, sarcoptic mange, rat-bite fever, ringworm, Salmonella infection, and Seoul virus infection. It says children younger than 5 and people with weakened immune systems are more likely to get a severe illness, and that pregnant women should not handle pet rodents, when possible, because of the risk of lymphocytic choriomeningitis virus.

Its habits for pet parents are specific. Wash your hands with soap and running water after handling small mammals and after touching or cleaning cages, play areas, bedding, water, and food. Do not kiss, snuggle, or hold small pets close to your face. Keep small mammals and their equipment out of the kitchen or anywhere food is prepared, stored, served, or eaten. Clean pet supplies outside the home if possible, away from gardens and sources of food or drinking water.

Feeding and Food Storage

A rat needs food made for rats. The RSPCA says pellets for rabbits, guinea pigs, hamsters, or other herbivores do not give rats the nutrients they need. If you also keep a hamster, AnimalHearted has a guide to the best hamster food for it.

The RSPCA calls rats omnivores and says to add small amounts of fruit, vegetables, cooked egg, grains, and seeds as part of the daily food allowance. Its list of foods to avoid includes onion, citrus fruits, walnuts, rhubarb, grapes, raisins, and chocolate. It also says to avoid sugary and high-fat foods such as dairy, and to use those only as treats and training rewards.

The RSPCA says to feed rats twice a day, in the morning and evening, and to remove any uneaten food. It recommends open ceramic bowls over metal ones, because metal makes ultrasound noise, and fresh water in bottles rather than bowls to avoid contamination. For the stored supply, UC IPM says to store pet food in rodent-proof containers. It also says rats can chew through plastic, foam, wood, and caulk.

UC IPM says wild rats are mostly active at night, and the RSPCA says pet rats are normally active at night, at dawn, and at dusk.

Cage Cleaning and Placement

The RSPCA says to clean the whole cage out once a week and to spot-clean through the week by removing faeces, soiled bedding, and uneaten food that is likely to go off. It says to leave a handful of unsoiled nesting material behind so familiar smells stay in the cage, and not to use air fresheners or other strongly scented products.

The RSPCA also says to check regularly that the cage is intact, because rats can chew through some materials such as wood and plastic, and that the bar spacing should be small enough that a rat cannot poke its head through. It says to keep the cage in a part of the house that does not get very hot or cold, not in a conservatory, garage, or shed. Our guide to the best rat cages compares cages with narrow bar spacing and slide-out trays.

Nests, Burrows, and Chewing

The UC guide says Norway rat burrows are found along building foundations, beneath rubbish or woodpiles, and around gardens and fields, and that nests may be lined with leaves, shredded paper, cloth, or other fibrous material. PetMD says pet rats tear, gnaw, and carry items back to their nest, and that in the wild they use leaves or moss.

Rats love chewing on things because their teeth never stop growing. PetMD says they rely on constant chewing, gnawing, and nibbling to wear down their incisors, and that without enough to chew, the teeth can become misaligned and abscessed. PetMD also says to rat-proof any area of the house the rat can reach, with electrical cords a particular concern.

The AnimalHearted guide to fun hamster tubes and tunnels covers tunnels made for hamster cages. Group housing helps with the social side: the RSPCA says rats can get depressed and develop abnormal behavior if they live alone, even with lots of human contact.

Signs of Wild Rodents Near Your Home

UC IPM says less time and effort are needed to deal with rodents when their numbers are low, so early signs matter. It lists these signs of a rat problem:

• Rat droppings around dog or cat dishes or pet food storage containers
• Noises coming from the attic or drop ceilings
• Burrows beneath a compost pile or beneath garbage cans
• Rat nests behind boxes or in drawers in the garage
• Smudge marks from rats rubbing their fur against beams, rafters, pipes, and walls

The guide says successful rat control combines sanitation, sealing the building, and population control, and that no repellent has been found to solve a rat problem for more than a very short time. It says traps should be kept out of reach of children and pets, and that all rodenticides are toxic to non-target species, pets, and humans, so a household with a pet rat should read the label and keep any bait out of reach.

Mice and Insects

Pet rats won't summon the neighborhood’s wild rodents for house parties, despite the common misconception that they do. Remember though, leftover gourmet nibbles can lead to unwanted guests like mice and insects, so a tidy house means no squatters, or at least it reduces the advertisement for free room and board.

Sources

• UC Statewide IPM Program, Rats
• RSPCA, Rats, with its diet and environment pages
• CDC, Small Mammals (Healthy Pets, Healthy People)
• CDC, About Rat Bite Fever
• Simola N. Rat ultrasonic vocalizations and behavioral neuropharmacology. Current Neuropharmacology, 2015 (link in the text above)
• Adams DB and others. Competitive and territorial fighting: two types of offense in the rat. Physiology & Behavior, 1994 (link in the text above)
• PetMD, 10 pet rat behaviors and what they mean (link in the text above)

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