A Perfect Storm of Jumping Mice

I guess I was just in the right place at the right time. I was in a part of the western Adirondacks where the soils are sandy–they’re called glacial outwash soils, and they’re a gift from our glacial past. After a day with several heavy downpours the weather cleared, and the next morning I went out to look for tracks. I headed to one of my favorite spots, a sandy truck trail that meanders through a mosaic of wet meadows, marshes, and shrubby uplands. The low spots in the road had filled with water during the rain, but the sandy soil had allowed the pooled water to drain away, leaving perfect tracking mud.

And there were tracks aplenty, mostly small rodents. But not just the usual small rodents–many tracks had the distinctive features of a very special animal. In the photo below (direction of travel toward the top) the five-toed hind tracks are in the upper section, nearly even with each other and set widely apart. Below them are the four-toed front tracks, one leading the other and set more narrowly.

These are the tracks of a small rodent called the meadow jumping mouse. (It’s cousin, the woodland jumping mouse, is restricted to boreal forests and would not have been found where I was tracking that day.) The meadow jumping mouse is pictured in the photo below by Martha Beck (from her blog, Martha’s Blog). This beautiful little creature has a very long tail, large ears and eyes, long back legs, and really interesting rear feet.

Here’s another example of the tracks I found that day. The direction of travel is toward the right, and the front prints (on the left side) are distorted by the impact of landing from a long jump. Nevertheless you can see that the rear tracks (on the right side) are much larger than the front,

especially in this example in which the entire lengths of the rear heels touched down. These long heels are unique to the jumping mouse, as are the long, slender toes. The three central toes are often slightly curved, and they spread more than the corresponding toes of most other small rodents. Another special feature lies in the elongated middle pad area of the rear prints. The inner and outer toes attach considerably behind the area where the three central toes come together.

In the photo below, another one from that amazing day, the elongated middle pad area shows nicely in the left rear print (farthest to the left). The right rear track is on the extreme right, the two front tracks lie between the two hind tracks, and the direction of travel is toward the top. Some interesting details of the front prints can be seen in the right front print (the lowest of the group): it’s canted toward the outside, with the innermost toe pointing up and a little to the left, the toe next to it pointing almost directly upward, the third toe pointing toward the right, and the outermost toe pointing downward. The middle pad area of this track is in the center, and the paired heel pads show at the lower left edge of the print.

Once you’re aware of the critical details, jumping mouse tracks look very different from the tracks of other small rodents. The meadow vole tracks in the photo below, also from that wonderful day on the sand road, are in the same relative positions as the jumping mouse tracks in the previous photo. But the front and rear prints of the meadow vole are similar in size and there is no elongation of toes, heel, or middle pad. The inner and outer toes of the hind tracks show as small ovals on either side of the middle pad area, and the front tracks are only slightly angled.

Although their feet are larger, jumping mice are actually much smaller than meadow voles, but they’re similar in size to another common small rodent, the white-footed mouse. But white-footed mouse tracks are also very different from jumping mouse tracks. The white-footed mouse tracks in the photo below (direction of travel toward the top with hind tracks above and front tracks below) are tiny compared to jumping mouse tracks, and the toes in both front and rear prints are small ovals with no connections to the middle pad. The three central toes of the rear print are close together and parallel with each other, and the middle pads are a distinct series of bumps.

My walk along the sand road that day was a real revelation. Although the drying mud puddles may have been more attractive to jumping mice than to other small rodents, I still have to believe that the abundance of jumping mouse tracks indicated high population numbers. Those scattered, moist habitats were just the kinds of places favored by meadow jumping mice, and the muddy low spots were perfectly situated to capture the animals’ movements. Since jumping mice spend the winter in extended hibernation we don’t have the luxury of seeing their tracks in snow. But a perfect storm of favorable influences created conditions rivaling the best snow tracking, revealing jumping mouse tracks like I’ve never seen them before.

9/26 – I just got a comment from Janet Pesaturo about the range of woodland jumping mice, which is broader than I realized. They’re found in mixed softwood/hardwood forests in temperate zones as well as in boreal forests. Thanks, Janet.