Exactly I pointed that head movement on the first page I Your point about not being able to see is a good one
You would expect some jerkiness in the movement but there is not during any part of the video
you'll notice a bald area close to the right side rib cage.
Researchers believe that is an area of wear from the creatures elbow constantly rubbing the area during years of walking around. The arm swing is actually right on top of this area if you look closely
Both guys described the creature in a state of contempt Not aggressive anger but the feeling like they disturbed something while it was in the middle of doing something
and it was mad it had to leave