There are lots of hypotheses on how to determine the sex of a deer or elk from its footprints. The following technique was shown to me by my tracking mentors, and I have tested it on hundreds of deer, elk, hog, and a few bighorn sheep trails. When I encountered the trail of an ungulate fresh enough to follow, I would make an educated guess as to the animal’s sex. Then I would follow the trail and find out if I was right by seeing the animal. It works nearly all the time. The exceptions are young bucks and big does/cows/sows/ewes. Often mature buck/bull/boar/ram tracks are obvious from their size alone. However, sometimes a more detailed look is required.
First, find a set of tracks where the front and hind foot are clear, not overlapping, and there is no unusual movement in the track (deeply splayed prints, slipping spoor, running animal). Second, find a straight grass stem or twig. Third, measure across the width of the front foot approximately in the middle of the track and hold the stem between your fingers so as to mark the width of the track. Now compare that width to the hind foot at the same halfway point. Ungulates with a proportionately wider front foot are more likely to be male, whereas those with similar dimension front and hind feet are more likely to be female animals.
In the accompanying picture I am holding the grass stem across the hind foot track with my fingers marking the width of the front foot. You can see a ¼” extra width of the front foot, indicating this track is from a bull elk. Often, behavior and size alone are enough to distinguish the sex of an animal’s trail, but this technique provides another useful tool for the detective hunter.