The woodland jumping mouse – a true hibernator

Woodland Jumping Mouse   Napaeozapus insignus Preble

Order: Rodentia    Family: Zapodidae

Have you ever wondered where jumping mice disappear to in the winter? Maybe not, as they aren’t very common even in the warmer months and some, like the woodland variety tend to be nocturnal. I chose this little guy because I have had some very cool encounters with its cousin, the meadow jumping mouse, watching nearby as it climbed dandelion stems and hung upside down by its long tail like a monkey as it ate seeds. Even though jumping mice walk, they can take huge leaps when startled then freeze in place, remaining motionless for hours staying hidden by their leafy coloration. Whereas you may see many deer mice or white-footed mice, you will rarely see these rodents, as they each call several acres their home territory.

Unfortunately, I have never seen Napaeozapus insignias Preble, as it lives in the forest (preferring beech, maple, birch and basswood intermixed with conifers), and is mostly nocturnal. It mainly eats subterranean fungi, Endogone from under the leaf litter and soil.  They also eat seeds, fleshy fruits, roots, leaves, spiders, caterpillars (including the gypsy moth caterpillar) and beetles. They do not cache food for winter nor do they have cheek pouches for storing food like chipmunks. The reason for this is that they are true hibernators, along with the groundhog who loves my garden. By September, they are putting on extra fat, up to one-third total weight; curled up underground in their burrow, which they have either dug themselves or taken over from another animal, where they become torpid (inactive with slowed metabolism). Adults hibernate first, by September, juveniles a month later. In the spring the males emerge by mid-April and the females, two weeks later.

The dangers for a Napaeozapus are not having enough stored fat to last the winter; indeed up to 75% will die from starvation every year. Another problem is flooding; they prefer moist areas, sometimes borders of ponds, swamps or bogs and if there is flooding in the spring, they will drown.

Sources:

Saunders, D. A. 1988. Adirondack Mammals. State University of New York, College of Environmental Science and Forestry. 216pp.

The Virtual Nature Trail at Penn State New Kensington http://www.psu.edu/dept/nkbiology/naturetrail/speciespages/woodlandjmouse.htm(Information for this species page was partially compiled by Sarah Allison for Biology 220W at Penn State New Kensington in Spring 2000)