Yes, mice do eat cat feces. While it might sound strange, cat waste contains enough residual protein and fat to attract rodents looking for an easy meal. This behavior is well documented and can create real problems in homes where cats and mice coexist, including the spread of a parasite that specifically evolved to pass between cats and rodents.
Why Mice Are Drawn to Cat Waste
Cats are obligate carnivores, and their digestive systems don’t extract every bit of nutrition from food. The leftover protein in cat feces gives it a smell that registers as a food source to scavenging animals. Dogs are notorious for seeking out cat feces for the same reason. Mice are opportunistic feeders that will eat almost anything with caloric value, and cat waste fits the bill.
The litter itself can also be part of the attraction. Corn-based and wheat-based cat litters are made from grains, which are a natural food source for mice. Pet owners who use these products sometimes find mice chewing through bags of unused litter or burrowing into the litter box to snack on the litter alongside the feces. If you use a plant-based litter, you’re essentially placing a food bowl and a toilet in the same spot from a mouse’s perspective.
The Parasite That Exploits This Cycle
The relationship between cats, mice, and feces is at the center of one of nature’s more unsettling parasitic life cycles. Toxoplasma gondii is a single-celled parasite that can only reproduce sexually inside a cat’s gut. When an infected cat defecates, it sheds microscopic egg-like structures called oocysts into the environment. According to the CDC, rodents and birds become infected after ingesting soil, water, or plant material contaminated with these oocysts. The oocysts then transform into an active form of the parasite shortly after being swallowed.
Once inside a mouse, T. gondii takes up residence in the brain and muscle tissue. Research has shown that infected mice become less fearful of cats and may even be attracted to the smell of cat urine. This behavioral manipulation makes the mouse more likely to be caught and eaten, completing the parasite’s journey back into a cat. So when a mouse eats cat feces, it isn’t just scavenging. It may be stepping into a transmission cycle that has been refined over millions of years of evolution.
For humans, this is worth knowing because T. gondii can also infect people. You won’t catch it from a mouse eating your cat’s litter, but the same contaminated feces that attracts rodents is a potential exposure route for anyone handling the litter box without washing their hands afterward.
Signs That Mice Are Visiting the Litter Box
Mice are nocturnal, so you’re unlikely to catch them in the act. Instead, look for small, dark droppings near or inside the litter box. Mouse droppings are about the size of a grain of rice, much smaller and more uniform than anything your cat produces. You might also notice tiny tracks or tail drag marks in scattered litter on the floor around the box.
Chewed bags of cat litter are another giveaway, especially with corn or wheat-based products. If the litter level seems to drop faster than your cat’s habits would explain, mice may be eating it. Some pet owners also report finding small tunnels or burrows inside the litter itself.
How to Keep Mice Out of the Litter Box
Frequent scooping is the simplest deterrent. The less waste sitting in the box, the less attractive it is. Cleaning the box at least once a day reduces the smell that draws rodents in. A covered litter box with a smaller opening can also make mice feel less comfortable entering, since they prefer spaces with multiple escape routes.
Switching from a plant-based litter to a clay or silica-based option removes one layer of attraction. If you prefer corn or wheat litter, store unused bags in sealed hard plastic containers rather than leaving them in the original bag, which mice chew through easily.
The most effective long-term solution is sealing the entry points mice use to get into your home. Mice can squeeze through gaps as small as a quarter inch, so check around pipes, vents, and the base of exterior walls. Steel wool stuffed into small gaps works as a temporary barrier since mice can’t chew through it, but permanent fixes with caulk, cement, or metal flashing are more reliable. Rockwool insulation slows mice down but won’t stop a determined one.
Placing the litter box in a room your cat can access but mice find harder to reach, like an upper floor or a room with a tightly sealed door and a cat flap, also helps. Keeping the area around the box clean of scattered litter removes the trail of food crumbs that leads rodents to the source.