Sitting around a campfire after dusk, it is sometimes possible to catch sight of a small rodent bounding across a section of the forest floor that is illuminated by the glow of the flames or a bright moon. Similarly, a small creature may occasionally be seen in the headlights of a car leaping across a road like a frog, but at a distinctly faster pace. The chances are that both these sightings are of the woodland jumping mouse, a small rodent that is fundamentally different from the species of mice that begin to enter homes and camps toward the end of summer.
On those rare occasions when one of these common forest dwellers is seen around a lean-to or tent, it can be easily mistaken for a regular mouse, as both rodents are nearly identical in size and have similar body shapes and facial features. The jumping mouse however, has a set of hind legs slightly larger than those of a regular mouse. These rear appendages are better adapted for catapulting its body forward when it wants to quickly escape a location. The jumping mouse is known to bound up to three feet at a time, which is ten to fifteen times the length of its body. Along with traveling in a straight line, the jumping mouse can also hop in a more erratic manner, making it more of a challenge for a predator either on the ground or from the air to grab it while it attempts to reach a place of safety.
The most conspicuous physical feature of the jumping mouse is the extraordinary length of its tail which can approach twice the length of its head and body. The tail of a normal mouse is roughly equal to or slightly greater than its body length. The much longer tail of this rodent often becomes noticeable when it is hunched up, nibbling on a berry or a favored mass of fungi which it has just unearthed from the uppermost layer of soil.
As its name implies, the woodland jumping mouse inhabits forested settings, especially where numerous ground plants and shrubs cover the forest floor. This mammal also shows a preference for wooded glades where the soil remains moist in summer. Lowlands along the edges of marshes and swamps, or places where natural drainage is poor and water seeps into the soil rather than runs off, are ideal locations for this abundant creature.
Because the jumping mouse prefers to forage under the cover of darkness, this rodent is not as likely to be seen prowling the forest floor as a chipmunk. Also, since it rarely utters any sound, there is little to draw a person’s attention to this mammal’s presence.
As August arrives, the jumping mouse begins to increase its intake of food. This is partly the result of longer nights for foraging, and an increase in the berries, ground dwelling bugs, and maturing fungi upon which it feeds. The excess food consumed as summer wanes is stored as fat. While a normal mouse begins to amass caches of food around this time of year for use in winter, the jumping mouse relies on its fat reserves to carry it through the colder months.
Unlike other mice, the jumping mouse lapses into a state of true hibernation as its food sources dwindle. After it retreats into a chamber deep in its burrow, the jumping mouse experiences a drastic drop in its body temperature as does the woodchuck and many species of bats.
In the Adirondacks, the jumping mouse is known to begin its winter dormancy as early as the middle of October. This is the time in the autumn when berries and bugs become limited in availability. While small seeds may still be present for this rodent to pick up from the forest floor, the new layer of dead leaves on the ground covers them and makes them harder to find.
Also, a fresh, dry carpet of dead foliage makes it harder for the jumping mouse to remain inconspicuous as it forages. The faint noise created by a mouse as it rustles through the dead leaves may be difficult for a person to hear, but it is more than adequate to alert any predator in the immediate area that a potential meal is active nearby. By slipping into a dormant state until conditions on the ground improve for it in mid spring, the jumping mouse is able to deal with the adverse conditions over the next 6 months.
As the moon develops in brightness over the next few weeks, an evening out in the woods may reveal periodic glimpses of this unique rodent which is active around most campsites here in the Adirondacks.
Photo courtesy Wikipedia.
Tom Kalinowski has written several books on Adirondack nature.