On my weekly nature walk through the forest last Thursday, a small set of four footprints in a muddy divot caught my attention. Irvine Nature Center’s naturalists and I took an up-close look and we concluded that the tracks were from an eastern chipmunk.And even more peculiar, we were quite positive that the tracks are from a male chipmunk. “How,” another staff member asked our group, “can you possibly tell the sex of an animal just from what you see in this mud?” It was, of course, a great question.