SCOTT SHALAWAY Flash of orange is likely a jumping mouse

If seeing is believing, this column could be a hard sell. Jumping mice are one of those common but seldom seen critters that are known only from field guides. But I've seen several in the past week, so I feel compelled to introduce these strange little mice.
Twice while mowing trails through a hayfield this week, I noticed a tiny burnt orange mouse hopping kangaroo-like across the path ahead of me. About a year ago a reader reported a similar observation and asked if it could have been a kangaroo mouse or rat. But he correctly pointed out that his field guide indicated they occur only in the dry southwest.
Meadow mice
What we both saw were jumping mice. They were probably meadow jumping mice, but another species, the woodland jumping mouse, is also a possibility.
Without having the mouse in hand, it's impossible to know which species we saw, but their natural histories are similar, so I'll treat them as one.
Jumping mice are tiny mammals (they weigh a bit more than a chickadee) with huge rear feet and a tail that's a good bit longer than the body. Their bellies are white and the fur on their back (what you glimpse as they bound out of view) is a rich orangish brown. But it is their orange front incisors that give them away: The front surface of each is deeply grooved. Although this is a definitive characteristic for identification, grooved incisors are not likely to be detected unless a cat deposits one on the doorstep.
Although jumping mice can walk and run, when hurried or frightened, they hop in zig-zag fashion. If just moving through open vegetation, each hop measures only 1 inch to several inches. But when frightened, they can jump 6 to 10 feet.
That's usually startling enough to elude just about any predator. And that's good news for jumping mice because they're on the menu of owls, weasels, skunks, bobcats, foxes, and snakes.
Preparing to hibernate
The most fascinating part of the jumping mouse life history is unfolding right now, and it probably explains why I've seen two recently. They are in a feeding frenzy to fatten up for hibernation. Jumping mice are true hibernators. For the next four to six weeks they devour seeds, berries, roots, nuts, underground fungi and invertebrates -- up to half their body weight each day.
By late October or early November, they're ready for the big sleep. Although they live and nest above ground during the spring and summer, fall sends them underground. They dig a burrow that may extend 3 feet below the surface and build a grapefruit-sized nest of grass and leaves.
When the nest is complete, they plug the tunnel and assume a distinctive sleeping position. Jumping mice curl into a tight ball by placing the nose between the hind legs and wrapping the tail around the body. Hibernation lasts up to six months. Body temperature drops to 35 to 40 degrees Fahrenheit, and the heart and breathing rates slow drastically. In late April or early May, jumping mice emerge to a bountiful crop of lush spring vegetation.
More than half of hibernating jumping mice fail to survive the experience, so breeding to replenish the population dominates the rest of the year. Summer nests are small balls of vegetation placed beneath a log or inside a large tuft of grass. Following a gestation period of just 18 to 21 days, four to six pups are born. Each weighs less than one gram.
Fast breeders
In less than six weeks, young jumping mice are sexually mature, and mice born in the spring's first litter usually breed their first summer. Adult jumping mice raise two and sometimes three litters per year. So though mortality during hibernation is high, the reproductive rate of jumping mice is more than enough to compensate for the losses and maintain a stable population.
Yes, seeing is believing, so keep your eyes peeled on your autumn walks. If you spot a tiny orangish mouse hopping across your path, you've seen a jumping mouse.
XSend questions and comments to Dr. Scott Shalaway, R.D. 5, Cameron, W.Va. 26033 or via e-mail to sshalaway@aol.com