ANIMATED MASK. “The advent of mammalian apomorphies related to the face is associated with the most mobile and ornamentally patterned faces among all vertebrates. Mammals have the ability to deform the facial mask (including movement of the vibrissae) and the external ears via contraction of the mimetic muscles.”
http://onlinelibrary.wiley.com/doi/10.1111/joa.12440/full