March 2018 Natural Mystery Answered

For our March Natural Mystery, we had one common, familiar species leaving tracks that resembled another common, familiar species. Donnie Phyilliare worked out the puzzle and offers this clear breakdown for us:

At first glance the temptation is to assume largomorpha or rabbit because of the "T" shaped bound also known as a 1/2 bound. Another bounding animal we must consider are tree squirrels so let's take a look at our three best candidates the eastern cottontail, eastern gray squirrel, and red squirrel.

Although a 1/2 bound is not common with tree squirrels they are very capable of this gate and will from time to time do just that. So what are some of the features we want to notice when trying to identify this set of tracks? First in snow, rabbit tracks appear to be thumb or bullet shaped [ed: except when they splay their toes wide, in which case the tracks can appear more circular] where on squirrels you get more of an ice cream cone shape that oftentimes has a flat top. Since the foot structure of a rabbit is very ridged the two hind feet are parallel to each other to allow for quick turns and rapid acceleration. Squirrels have the option of climbing trees to escape danger so a foot that can rotate 180 degrees is more advantageous for an animal that spends much of its time in trees and allows the animal too descend head first down a tree. If you look at the photos you will notice tracks that look like ice cream cones and hind feet are turned slightly outward so we can eliminate rabbit.

Looking at the trail width of the two hind feet the width falls in line with that of a red squirrel, but there's one more thing we need to take into account. This bound is stretched out meaning the animal is moving at a fast pace and as speed increases the trail width will narrow so taking that into account we can probably rule out red squirrel. This leaves us with eastern gray squirrel as the track maker.

Exactly correct. This is the trail of a gray squirrel, dashing between oak trees in Phalen Park. The photo below, from a little farther along the trail, shows the rear foot morphology more clearly. In this set, the rear feet are offset as well--showing a pattern more characteristic of a ground squirrel than a tree squirrel--but this trail was made in December, when all our self-respecting "golden gophers" are hibernating!