Unloved Nature — Wee Beasties
I’m truly sorry Man’s dominion
Has broken Nature’s social union,
An’ justifies that ill opinion,
Which makes thee startle,
At me, thy poor, earth-born companion,
An’ fellow-mortal!
From “To a Mouse” — Robert Burns
House Mouse (Mus musculus)
Get Amy Yarger in Nature Nearby’s stories in your inbox
Join Medium for free to get updates from this writer.
One of my favorite stories as a child was “The Tale of Two Bad Mice” by Beatrix Potter. In this tale, a pair of opportunistic mice, Tom Thumb and Hunca Munca, find a dollhouse and move in, only to find the accommodations not as comfortable as they thought. Who can blame them for smashing that fake ham? The mice eventually move back to a cozy hole (in the main house, mind you!) and teach their young ones about traps and other dangerous things. Equilibrium is restored- yet another example of the fact that if you make habitat, even unwittingly, other creatures will make use of it, whether you welcome them or not.
Hunca Munca and Tom Thumb are both depicted as house mice, rodents belonging to the family Muridae, along with other kinds of mice and rats. House mice tend to have pointy snouts, roundish ears, and a bald tail. The ones we see running like a streak across the floor tend to be brown or gray, but of course, there are fancy mice bred as pets that turn out white, pink, or even champagne-colored. Other mice, such as deer mice, might come inside for food and shelter sometimes, but it is house mice that have joined their fate with humans in their built environments for the past 15000 years.
Scientists think that Mus musculus originated as a species in southwestern Asia. Once humans began storing food and building stationary settlements, M. musculus stayed close by. The development of agriculture was another windfall for these critters, and eventually they hitched rides with travelers and made it to the eastern Mediterranean around 13,000 BCE. Is it any surprise that the domestication of cats seems to have taken off in earnest around 10,000 years ago? By the time English colonists made it to North America, house mice came along with them.
So house mice are domesticated — it’s unusual to find them outside human structures — and yet not. They make nests in the walls with pillow stuffing and torn up napkins, eat our foodstuffs, poop all over our belongings. They are characterized as pests. But let’s acknowledge that the pest label overshadows the tremendous adaptations of house mice. They can run 8 miles/ hour, jump 18 inches in the air, climb a vertical surface, stand on their hind legs, and even swim. They can fit through a crack the size of a pencil eraser, 1/4 inch wide. And their behavior is as intense and soap opera-ish as any nature documentary.
For one thing, male house mice defend their own territories, which are marked with very smelly urine. If you’ve ever been somewhere with a lot of mice, you will recognize that odor! They then court Ms. Hunca Munca with ultrasonic calls, often compared to birdsong in their complexity and variety. After the union, females then develop a mating plug to prevent further sex for a day. After about three weeks, the female may birth 3–14 blind, bald pups. A female is sexually mature at 5–7 weeks and then can have 5–10 litters a year under good conditions. Get out your calculators — that comes to over 5000 mice generated from an original pair. No wonder house mice can reach “plague proportions” of 1000 mice per hectare under certain conditions.
Mice usually live less than a year, but the lucky ones may survive 2–3. There is a Methuselah Mouse Prize to engineer very old mice, and the current winner almost made it to 5. Calorie restricted mice also can live over 4 years. But typically, the life of a house mouse is brutal and short. Owls, cats, foxes, snakes, hawks… everyone wants to eat mice. They think it’s nice! Thank goodness for these natural predators, or we would probably be commuting to work, having dinner, watching TV under a thick blanket of mice every day. No one likes to have their personal effects chewed or pooped on, but the main concern for most of us is zoonosis: mice can carry diseases such as leptospirosis, hantavirus, and even serve as a host for Lyme disease.
However, people are funny creatures, and all the while we are trying to get rid of mice, we are also relying on them as biomedical test subjects in labs around the world and idolizing them in popular culture. In stories such as “Stuart Little” and “The Mouse and the Motorcycle”, the mouse is the underdog, a sympathetic protagonist. For those of us raised on these stories, finding a dead mouse in a snap trap can be a sad affair; one can’t help but think of the tiny life snuffed out. That doesn’t mean I want them eating my cereal, though.
If you have to remove mice already in your house, trapping is your best bet — it keeps poison out of the food chain, plus you can get rid of the dead body instead of having them rotting and stinking in your walls. Snap traps are easy to get, inexpensive, effective and fast-killing most of the time. In my household, we’ve had success with a peanut butter- pepperoni mixture as bait. Live traps are often not recommended, since being trapped is very stressful and released mice are likely to die miserably from exposure, starvation, or competition with the locals. Also, some states have made releasing rodents into the wild illegal.
Rodenticides, which are poisons meant especially for mouse and rat control, work by preventing blood clotting, which means a slow (up to 10 days!), tortuous death and enough time for another animal to come upon it and eat it. If the mouse has enough poison to kill it, it can also affect the animals that eat mice, such as bobcats, foxes, hawks, and more, weakening immune systems and building up over time if the predators eat more poisoned rodents. CA Fish and Game found that 90% of mountain lions and 88% of bobcats had rat poison in their systems. The US EPA also estimates that more than 100 pets die annually from eating rodent poison. If you do need to hire a contractor for mouse control, make sure the company is certified by Ecowise and/or Greenshield and that they are willing to use integrated pest management to address the mouse issue.
As it is with most household pests, prevention is the best approach. I think it would be smart to spread a new fall tradition before the mice move indoors for the cold season. That tradition, timed with the start of Pumpkin Spice season, would include moving brush and debris at least 2 feet from the house, filling gaps with steel wool mixed with caulking compound, and putting dry goods in mouse-proof containers. For good measure, maybe we’d clean our outdoor grills and make sure our trash cans close securely. It wouldn’t be a new idea — some Balkan countries used to celebrate an annual Mouse Day to protect their crops from ravaging mini-beasties. But perhaps to our autumn Mouse Day, we could add a wee pause of appreciation for a global survivor, a problematic roommate, an animal who shares millennia of history with us.
