Winter is not my favorite season. I shiver when the temperature dips below 70° F. Shoveling snow is boring, endless, and my doctor agrees that it’s bad for my health. And yet… when I stop whining and strap on my snowshoes… something wondrous happens. I step into a world that lies hidden the rest of the year.

Animals that slip silently through the night in summer leave tracks in this new wintery landscape. Some footprints are so clear I can count the number of toes. But even trails that look exactly like dents in the snow give up their secrets when I measure the size of each imprint and the distance between them. The patterns help, too. (By pattern, I mean the arrangement of the animal’s feet. When gray squirrels bound across the lawn, each landing creates a neat rectangle. Rabbits’ paws form a triangle after their leaps.) Comparing my results with a field guide tells me what species probably—probably is the operative word, here—traveled through my yard between sunset and dawn.

Are you interested in being a wildlife detective? All you need are a measuring tape or ruler and a field guide. Just make sure the book you choose has good pictures or drawings; tells you what to look for; and includes measurements and typical trail patterns. My personal favorites are Tracking and the Art of Seeing by Paul Rezendes and The Peterson Field Guide to Animal Tracks by Olas J. Murie et al., but there are many others out there.

Happy tracking!