Some interesting toothwork on trail markers in North Alabama: Almost every metal sign on the trails at the Land Trust of North Alabama’s Monte Sano Preserve is incised with dozens or hundreds of striations.

The artist? Gray or fox squirrels? We saw plenty of grays. Perhaps night-working flying squirrels? I’d welcome your thoughts!

Rodent incisors grow continually through their lives, a self-renewing mechanism necessitated by the walnut cases, seed husks, and other rock-like coatings with which plants so inconveniently wrap their progeny. These ever-growing teeth need continual shaping and sharpening. Might this be the reason for the rodents’ attention to the trail markers? I’ve seen similar markings on horn and bone. But these biological remnants are calcium-rich, unlike aluminum trail signs. It would be interesting to hang some files in the woods and watch the evolution of dentistry.