>>4986296
It's mainly a matter of how we perceive their supraorbital ridge, those sunshade structures above their eyes that gives them that "scowling eyebrow" look when viewed from certain angles, especially from the front.
We, with our expressive, moving eyebrows, interpret it as an emotional display or mood indicator, a function it does not have.
It's a problem we have with other Animals as well, that don't use facial articulation to communicate moods or emotions. To us, a Dolphin will seem to be happy and smiling, even if it is very upset or angry, whereas a Vulture will seem to be forever angry or upset, even when it's as happy as can be.
