Why Do Mice Chew Wires?

Maybe your car won’t start. Perhaps your lights won’t turn on. Probably, you have mice. Mice are notorious for getting into tight spaces and chewing through wiring, destroying things, and causing costly repairs. But the problems with chewed wires go far beyond inconvenience and large bills. Mice chewing on wires in your home can be incredibly dangerous, as electrical problems are a major cause of house fires. It is estimated that chewed or damaged wires due to mice may be the cause of up to 20% of undetermined structure fires in the United States. But wires and cords aren’t a food source and don’t look appetizing, so why do mice chew on them?

Mouse Teeth Grow Constantly — And Fast

Just like in other rodents, mice’s teeth never stop growing. Mice have two long incisors in the front of their mouth on both their top and bottom jaws. These incredibly hard teeth need to be constantly worn down so they don’t become overgrown. Wearing the teeth down requires the friction that comes from biting and gnawing. So, to keep their teeth in good shape, mice have to chew — a lot. Mice chew so much that they wear their four incisors down and completely renew them in just 35-45 days.

Many people think mice chew on wires because they like the taste and want to eat them, but attempts at making wire insulation distasteful haven’t been successful. Even wrapping wires in tape infused with spicy capsaicin has failed to deter mice from chewing on wires! This implies that the mice aren’t attracted to the taste of wires, but to the convenience they provide. Wires, cables, and cords are plentiful in houses, garages, and cars, making them a popular thing for mice to chew on. Additionally, wires are round and small, which makes them convenient for mice to hold on to while they chew.

Wire Gets in the Way

Mice and other rodents like to live in dark, secluded places. This makes walls, car engines, attics, and garages the perfect place for them to make a nest. One thing all of these locations have in common? They have wires running through them.

If a mouse is trying to make its way through a wall, wires may get in their way. To eliminate the obstacle, mice will chew through wires to make the easiest path. While wire is comprised of metal surrounded by plastic insulation, it’s no problem for a mouse. The core of wire is made from copper, which is a soft metal that mice can easily chew through.

While mice can chew through copper, they often don’t. This is actually the most dangerous situation. If a mouse chews the insulation off of a wire and leaves the wire exposed, the wire could start a fire. Bare wires touching other bare wires can short out circuits. Additionally, if the exposed, hot wire comes in contact with insulation or other materials around it, it can easily spark a fire. This can backfire on the mice as well: a mouse can easily electrocute itself by chewing through wires.

Preventing Mice From Chewing Wires

If you think you might have mice chewing on your wires, there are certain things you can look for. Frequently tripped circuits, flickering lights, power fluctuations, burning odors, or visible bite marks on cables are signs that you may have a rodent problem. Once mice are in a space, it can be difficult to get rid of them. However, there are a variety of traps and repellants on the market that can help you effectively and humanely remove mice from your home. You should never poison mice to eradicate them on your property, as it can accidentally be ingested by domestic pets, children, or wildlife.

The best way to stop mice from chewing wires is to prevent access in the first place. Eliminate access points to your house or garage by filling in entry points and holes. Mice can fit through holes just a quarter inch in size, so it’s important to seal holes completely. Some species such as deer mice can easily climb trees to access houses from above, so it’s important to inspect attics and eaves for potential entryways as well.

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