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Those very unwelcome visitors in the night — mice

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If you have ever heard scrabbling in your cabinets and discovered mice, it is a sound you never forget.

Years ago, on a trip through the Shenandoah National Park in Virginia, we stayed overnight in an adorable little cabin. There was a sign there telling you to clean up after your meals and lock your food in the car trunk. Maybe I was lazy and figured I would wing it, but that night we heard that telling noise and found that we had been invaded.

Yes, we packed everything up in the middle of the night and put it where it belonged.

Many years later, we found evidence of a mouse intrusion in our home. We didn’t hear the animals, but found droppings, which was worse. I no longer remember exactly how we attempted to catch the varmint, but it evaded us for so long that we took to calling it Einstein.

Eventually, we resorted to serious measures, and Einstein was no more.

Two weeks ago, we found mouse evidence again, and one afternoon I heard the dreaded scrabbling. We found the cabinet that held their preferred foods — I’ll never look at a pretzel the same way again — but this time we played hardball immediately.

So far, the count is Jeselsohns 3, Mice 0 — if you don’t count the pretzels.

While I do not want mice moving into the house, they are far cuter than their rodent relatives, the rats. Both mice and rats are members of the order Rodentia and family Muridae.

In fact, there is a whole group of mice known as “Fancy Mice” (subspecies Mus musculus domesticus), a domesticated version of our visitors, the house mouse (Mus musculus) that are sold as pets. This is an old tradition with the first reference to mice as pets found in a Chinese dictionary from 1100 B.C.

Considering the standard comic meme of people squealing and running from mice, there are clubs all over the world devoted to these animals. In the United States there is the American Fancy Rat & Mouse Association formed to “promote and encourage breeding and exhibition of fancy rats and mice.” They even have shows several times a year in southern California where judges evaluate animals based on official standards.

Fur colors include the startling red, silver, and navy blue, as well as the standard range from white to chocolate.

Today there are four different Mus species:
• Mus spretus — the western Mediterranean short-tailed mouse,
• Mus macidonicus — the eastern Mediterranean short-tailed mouse,
• Mus spicilegus — the mound-building or gleaning mouse of Eastern Europe, and
• Mus musculus, the true house mouse, further subdivided into four subspecies found in Asia, Africa and the Middle East.

The house mouse has a long tail and has established an unwelcome involvement with humans. This association has spread the house mouse through European travels since the 15th century to the Americas, tropical Africa and many Atlantic and Pacific islands.

Sometimes the mice can be used to follow human migrations. For example, mice on the island of Madeira are related to mice from the Danish Viking mouse population, although there is no historical or archeological record of the Vikings ever visiting Madeira.

The earliest mouse ancestors appeared during the middle Miocene, 14 million years ago, with the first fossils of genus Mus found in Ethiopian excavations from three million years ago. The genus name Mus comes directly from the Latin word for “mouse.”

House mice live outdoors as well as in buildings. Since outdoor conditions are harsher for animals, there are some variations in their life cycle.

The pups look fetus-like at birth. They are blind, their ears are not fully developed, and they have no fur. Ears are fully developed by the fourth day, fur is apparent by the sixth, and eyes open by the 13th.

Weaning occurs around the third week, and the animals reach sexual maturity by the sixth week for females, and eighth week for males.

Litter size averages six to eight pups, and an indoor female can have between five and ten litters a year, while outdoor mice breed only between April and September.

Domesticated mice live about two years, while wild mice average 12 to 18 months.

No column about mice would be complete without mentioning the indispensable role they play as experimental subjects in all areas of biological and medical research. They also have been bred extensively for mutations allowing exploration of many human disease syndromes.

House mice are homebodies, not usually traveling more than 50 feet from their nests. I’m hoping that the mice we caught had their nest outdoors and we find that mouse hole quickly.
Otherwise we may find ourselves hosting unwelcome company again!

Have a thought or comment for Sura Jeselsohn? Email her at greenscenesura@gmail.com.

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