Walking the Rails

When I was a kid I used to enjoy exploring the woods and fields near my home, and one of my routes involved travelling along a seldom used railroad line. The rocky bed that supported the ties and rails was hard to walk on, and the spacing of the ties was just a little different from my natural step, so I often walked on one of the steel rails. Recently I found myself doing the same thing–walking along a seldom used railroad line and attempting to keep my balance as I walked on a rail. As I stepped carefully along I saw some peculiar muddy smudges on the rail ahead of me.

I thought at first that someone with muddy sneakers had been there ahead of me. But the marks didn’t look like the tread pattern of a shoe, and some of the groups of muddy spots seemed to form zig-zags rather than the centered prints that a person would make. My puzzlement turned to delighted comprehension as I noticed more details. The zig-zag sections were separated by areas that were smeared or had a jumble of muddy marks, such as the the area at the top right in the photo above. It was as if a walking animal had occasionally lost its balance and shifted its steps to keep from falling off the rail.

In the clearest impressions, arrays of small mud spots seemed to form half-circles around central clusters of smudges, as in the two photos below. The more I looked at them, the more the outer marks looked like toes and the inner clusters like middle pads. And those half-circles of widely separated toes, spreading across most of the top of the rail, could only have been made by an opossum.

Compare the images above with the photo of opossum tracks in mud (from a different opossum encounter) below–the left front track at the upper right and the left rear track below. Notice how the widely spread front toes encircle the middle pads; the upper two middle pads show as triangular impressions and the lower two as faint roughenings of the shiny mud surface. Four toes of the hind print point toward the upper left and the innermost hind toe–probably superimposed on the innermost front toe–points toward the right. The front print is a pretty good match for the mud-on-steel prints in the photos above.

Here’s another shot (from last winter) of opossum tracks, the left front on the right and the left hind on the left. The perfect tracking snow recorded the triangular to oblong middle pads of both front and rear feet beautifully. In the front print the position of the middle pads inside the circle of toes reproduces the positioning of the inner clusters and outer circles of mud marks in the tracks on the rail.

The positioning of the rear feet of a walking opossum is often erratic, and the animal that walked on the rail left many rear tracks that were smeared, distorted, or partly missing. In the photo below the middle pad area of the left rear foot (on the left side) made the large smudge behind the left front print (on the right), and the four outer toes of the rear track left spots and smears on the sloped upper edge of the rail. The lack of precision in the placement of its rear feet may have caused some missteps as the opossum attempted to balance on that three-inch rail.

Putting it all together, the whole scene made sense. I found the muddy slough the possum had crossed, coating its feet in ooze, before it climbed up onto the railroad bed. There were sloppy smears and spatters on the rocky shoulder of the railroad bed, and on the ties where it had first stepped onto the rail. The zig-zag pattern of the walking gait was occasionally punctuated by sections with extra steps and smeared mud where the opossum had struggled with its balance. (What would it look like if a more precise walker–like a cat–had left muddy prints on a rail?) At each step mud was transferred from the opossum’s feet to the rail, and the tracks grew fainter and finally disappeared. I continued in the same direction toward a road bridge which crossed the railroad line. Under the bridge there was a wide, dusty area, and when I stepped away from the tracks to investigate I saw a recently made opossum trail. Could it have been the same animal? I can’t be sure, but I feel a kinship with the opossum that made the muddy tracks. In spite of our balance problems we both found walking the rail to be a good way to get where we wanted to go.