Mice and Other Rodent Pests
2020 updates by Cathy Bickel
Uninvited mice in the home are a problem for gerbils, mainly because they carry diseases and mites. They are attracted to even the most minute spills of gerbil food and hay, which they find delectable.
The first order of business is to clean up scrupulously. Store gerbil food in particular in a chew-proof container, such as a metal tin or a crockery vessel.
If your gerbils live in an aquarium tank, then your chief concern is to keep mice off the lid. Mice generally like to stay low and out of sight, but at night they may be emboldened. Your best bets are to keep the gerbils as far away from where mice are spending their time, usually the kitchen, and to place the cages up high. Placing the cages up high is not a perfect answer, though, since mice can climb straight up a cement wall; little is beyond their climbing abilities. You can if you wish cover their tanks with a layer of cheesecloth so that at least if mice do traipse across, their feces won't fall into the tank.
Watch your gerbils for unusual itching or fur loss, which can be a sign of mites. Mites will also bite you. You may not feel the bite immediately but they generally become extremely itchy bites that get worse under heat. The bites usually look like round flat red areas with a small white or clear bump in the middle. Any sudden health issue in your gerbils, such as lethargy or loss of appetite, should not be ignored. If you have to take the gerbils to a vet out of some health concern, be sure to mention the invaders.
If you can, get the world's best mousetrap: a cat. Even just the presence of a cat, with its smell and hunting behaviors, will persuade the mice to move on. Poison traps should not be used, as the mice could carry the poison to the gerbils, and bits of rodent poison will be left around your home even after the mice are gone. Spring traps, if used, must be used with caution, and placed only in areas you are positive even an escaped gerbil won’t be able to reach.