Rats are excellent climbers, swimmers, and gnawers. They can squeeze through holes the size of a quarter, climb vertical walls, and travel through plumbing or wiring. Once inside, they’re drawn to pet food, garbage, and warm nesting spots. Your dog or cat may chase them, sniff their droppings, or even catch and eat them — all of which expose your pet to danger.

Smaller pets (ferrets, rabbits, guinea pigs, birds) are at even higher risk of direct attack or being killed. Larger dogs and cats are more likely to pick up diseases or parasites through contact with rat urine, feces, saliva, or nesting material.

One of the most serious threats. Rats carry the bacteria in their urine. Dogs (especially those who drink from puddles or lick wet grass) can get severely ill — kidney and liver failure are common. Cats are more resistant but can still carry and spread it.

Caused by bacteria in rat saliva or droppings. Pets can get it from bites or contact with contaminated surfaces. Symptoms include fever, joint pain, and lethargy.

Primarily a risk to humans through airborne particles from dried droppings, but pets can bring contaminated dust into the home and may show respiratory symptoms.

Rats carry Salmonella in their feces. Pets can get diarrhea, vomiting, and severe dehydration from eating contaminated food or licking rat droppings.

Still present in some parts of the U.S. Rats can carry fleas that transmit plague to dogs and cats.

Rats bring fleas, ticks, mites, and intestinal worms into your home. Your pet can pick these up simply by sniffing or walking where rats have been. Rats also chew electrical wires, creating fire hazards, and contaminate pet food and water bowls with urine and droppings that contain harmful bacteria.

Small pets like hamsters, guinea pigs, or birds can be killed outright by rats. Even large dogs have been known to get bitten on the nose or paws while investigating rat holes.

Prevention is far easier than dealing with an infestation:

• Seal all entry points (doors, windows, pipes, vents) with steel wool and caulk
• Store pet food in airtight metal or heavy plastic containers
• Keep garbage cans tightly closed and clean up spills immediately
• Remove clutter and woodpiles near the house
• Use pet-safe traps or bait stations placed where pets can’t reach them
• Consider professional pest control if you see droppings or signs of activity

Keep cats indoors at night when rats are most active, and supervise dogs in areas where rats may be present.