5 smells that mean mice


November 15, 2023

Photo: Dejan Kolar/iStock / Getty Images Plus/Getty Images

Buildings have many voids, nooks and crannies for mice to hide. Don’t give up the fight. Photo: Dejan Kolar/iStock / Getty Images Plus/Getty Images

Some strong odors can indicate there are mice at an account. With their small size and knack for squeezing into the tiniest of places, mice can get into the space completely undetected, which is where your nose becomes useful. What follow are five smells pest management professionals reported to the online lifestyle website Best Life can indicate mice in a home or business.

1. Ammonia

One of the most pungent or recognizable odors that signals a mouse infestation is ammonia.

“This smell is a result of mouse urine, which mice tend to scatter around as they move through your home,” says Lorne Hanewich, corporate trainer at Clark’s Termite & Pest Control, who adds that as the urine dries, it releases ammonia into the air, creating a strong, acrid odor.

Mice actually use their urine as a territory marker, so the odor is especially noticeable in small enclosed spaces or areas where they’ve nested. And as Ben McAvoy, founder of Insectek Pest Solutions, notes, mice do not have control of their bowels or bladder, which means they will urinate and leave droppings anywhere.

2. Fish

Georgios Likopoulos, a pest control expert at London, England-based Fantastic Services, notes that mice use various materials, such as paper, fabric and insulation for nesting. That, Hanewich chimes in, means that over time, these materials “can become soiled with urine and feces,” leading to a fishy odor.

Ryan Smith, owner of Ant and Garden Organic Pest Control, also points out that a fishy (and sometimes burning) smell may be due to mice gnawing on wires, which could lead to an electrical fire if left unattended.

3. Musty

Mice urine and feces that have been sitting untreated may also develop a musty smell.

“Whether fresh or old, when the droppings decompose, they release odorous compounds,” says Likopoulos.

To confirm the issue, McAvoy suggests using a black light to inspect for urine stains along cabinets, baseboards, or pantries.

4. Decomposition

While none of these scents are pleasant, decomposing mice are particularly awful, the article notes. This general odor will smell rancid or rotten.

“The odor of a dead mouse is a mix of sulfur dioxides, methane and other noxious gases,” according to Terminix. Decomposing mice can also emit a rotten cabbage-like scent.

Hanewich cautions that this smell can also pose health risks: “If you experience this smell, it’s essential to locate and safely dispose of the deceased mouse, as well as take steps to address the infestation.”

5. Sour food

“Mice often contaminate human food with their saliva, urine, and droppings,” says Likopoulos. If this has occurred, you can expect a sour/stale smell to come from the affected food.

It’s important to not only inspect your customers’ pantries and food items on a regular basis, but also to have them seal any open packages and store items in airtight containers.


About the Author

Ellen Wagner

Ellen Wagner is the digital editor for PMP magazine. She can be reached at ewagner@northcoastmedia.net.

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