A side view of a grizzly bear typically shows a concave or dish-shaped profile between the eyes and the end of its nose.
A side view of a black bear normally has a long, fairly straight profile from forehead to the tip of the nose.
Caution: Don't use the facial profile alone as a way to tell two bears apart. Male black bears may appear to have a square, broad face. Young female grizzly bears, especially in the spring, may appear to have a narrow face.
In general, when viewed straight on, the face of a grizzly bear appears dished and broad. The face and forehead of a black bear in the same view appears straight and narrow.