How does Smoke determine the location of the mother panther?

The correct answer highlights the role of scent marking in wildlife behavior. In many animal species, including panthers, fresh urine serves as a significant indicator of their presence in a particular area. By finding fresh urine on a fern, Smoke is likely utilizing his sense of smell, which is much more acute than that of humans, to pick up on the recent activity of the mother panther. This indicates not only that the panther has been in the vicinity, but the freshness of the urine can also give clues about how recently she was there, helping to narrow down her potential location.

Other methods, while plausible, may not be as effective for determining the location of the panther. Following tracks in the mud would require favorable conditions such as soft ground, which may not always be present. Hearing the panther's roar could guide Smoke to the general vicinity, but sound can vary greatly and might not provide precise location information. Spotting her from a distance in the trees requires visibility conditions that may not always be ideal. Therefore, locating fresh urine is a direct, reliable method that leverages the panther's natural behavior of marking territory.