How to keep a mouse out of your house

By Tim Lockley

I don't know why, but I haven't written an article on house mice in over three years. I used to get letters about them four or five times a year. Last week, I finally got one.

No matter what you think about house mice, you have to admit that they are an adaptive species. The common house mouse (Mus musculus) probably originated in Central Asia and began its worldwide spread along the ancient Silk Road, traveling to Europe, tagging along with the caravans. They, along with Norwegian rats, wharf rats and humans, are considered the most widespread terrestrial animal.

The typical mouse has light brown-gray fur with slightly lighter under parts. They have large ears, a pointed nose and a long tail. Mice can be found wherever humans are and in some places we aren't. Mice have made themselves at home in our homes as well as deserts, the tropics and mountainous areas. They can be found in cities, small towns and in rural areas. The house mouse isn't necessarily tied to the human race but it does seem to like being close to us.

Mice reproduce very rapidly. They have to. Every predator out there finds the house mouse to be a tasty snack. A female house mouse can become sexually mature in just six weeks from its own birth. Gestation lasts 19 to 21 days and, immediately after giving birth, a female mouse can mate and begin the whole cycle all over again. Under ideal conditions, a mouse can give birth every 25 days. Since a mouse can live up to two years, a single female can potentially produce over 3 million offspring during its life. I thank Mama Nature for all those predators.

So, what can you do if you don't want mice moving in on you? First, seal off all routes of entry including gaps in walls, around pipes and wires, windows and doors. Remember, a mouse can squeeze through a hole as small as a pencil eraser.

Next, even though a mouse will eat almost anything, it loves bird feed and dog and cat food. Don't leave any food out for your pets overnight (mice are nocturnal). Keep all of your food tightly sealed. Put your garbage in a container with a tight-fitting or heavy lid.

Set traps in any area where you find droppings. Bait the trap with peanut butter (a dab about the size of a pea is enough) and place against the wall away from curious kids and pets. If you catch any mice, remove the victim using a plastic bag turned inside out and disinfect the area with bleach.

Remove any trash and overgrown vegetation from around the outside of your home. They can use it to hide.

If you decide to take the poison bait route, set the bait in areas where your kids and pets can't get to it. Mice are nibblers and it might be a while before you notice if the bait is being consumed.

Remember, if you see one mouse, it doesn't mean that you have an infestation. However, left to their own devices, you could have a problem in short order.

Tim Lockley, a specialist in entomology, is retired from a 30-year career as a research scientist for the U.S. Department of Agriculture. For answers to individual questions, please send a stamped, self-addressed envelope to Tim Lockley, c/o Sun Herald, P.O. Box 4567, Biloxi MS 39535.