In this scenario, the student is a passive participant in the process. The information learned is impersonal. Clearly, the teacher is in control of the learning process; his or her interests dictate what and how fast the students learn.
The answer in all three cases is that rudder is used to help maintain stability in the roll. A little rudder at just the right time can help keep the nose up in a slow roll or even an aileron roll, as the plane rotates through the sideways portions of the roll when gravity is otherwise not countered.
A mink's tail probably serves as a rudder in the water, but little more, and, of course, helps with balance on the land. So it is not a motor. Mink dig more than otters and, I think, seek finer fare than what the gross scraping of an otter might dig up.