March 2022 Natural Mystery Answered

Last month’s Natural Mystery may be the last we see of snow tracks for a while. We received a few guesses on this odd print and one correct answer. Congratulations to Mark H who successfully identified the critter that left this print.

As Mark wrote, “This is the rear left foot of an opossum.”

I’ll let him explain:

"The main evidence is what appears to be an extreme angle of the thumb (Toe 1) to the other toes. The other toes are all well-aligned in a tight formation, which matches pictures of possum prints, and the negative space of the palm seems to match as well. The size of around ~65mm appears to match opossum."

Exactly right. In addition to the features Mark notes, the width of Toe 1, and the size of the metatarsal (palm) pad at the base of Toe 1 also point to this being an opossum track. Raccoon, woodchuck, and even muskrat hind tracks may look similar at first glance—but that thumb is diagnostic for opossums.

Mark did have a question about the impressions just above Toe 2 on the left edge of the track. These were left by toes of the front feet before being stepped on by the hind. Opossums usually walk with a slight understep. It appears that this individual was direct registering. Many mammals will leave direct register patterns in deeper snow, even when this is not their preferred mode at other times of year.

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