Question:

Can you tell me what mouse droppings look like please? I’m afraid that’s what I’m seeing in a couple of my kitchen cabinets.

Answer:

Mouse droppings are usually black, about 1/8 to ¼ inch long. They are thicker in the middle, narrowing at each end, usually to a point. In comparison, brown rat droppings are much bigger, about ½ to ¾ inch long, and blunt at both ends.

A single mouse will deposit about 70 droppings a day, a few at a time. Mice don’t have a regular bathroom place. They leave their droppings randomly wherever they travel: along their runways (or paths), in corners, and near their food. They usually do not leave droppings in their nests, however.

At 70 droppings a day, one mouse can leave behind 25,000 droppings in a year! And those droppings don’t really decay.  You can easily find mouse droppings that have been in place for years. That’s why it’s important to be able to tell the difference between fresh or recent droppings and those that may be very old. Fresh droppings are usually shiny black and look wet or glistening. Fresh droppings are soft with a putty-like feel. After a few days, mouse droppings become drier and brittle. Old droppings crumble when crushed while fresh droppings do not. Very old droppings change from black to grayish and may be moldy or dusty-looking. If the mice have been feeding on colored rodenticide bait, droppings can be various colors such as green, blue, or pink instead of black!

Some experts will make extrapolations about the numbers of mice in a site based on the amount of droppings. As you already know, that can be tricky unless you are very good at telling new droppings from old droppings. It’s also why pest control technicians will sweep up mouse droppings in an account. Then when they return, they know that any droppings are recent, deposited since their last visit—and that means there is still a mouse problem.

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