Baleen whales have a long upper jaw, narrow and arched or wide and flat, with baleen plates for sieving food from the water, flatness of the head above eyes and double blowhole. Toothed whales have a narrow straight upper jaw, at least one pair of teeth in lower jaw, a 'knob' above the eyes and upper jaw and the blowhole is high up on the forehead. Baleen whales have wide separated lower jaws. Toothed whales have very narrow lower jaw consisting of two jawbones fused together. Eyes are small with no eyebrows or lashes.
Ears are normally difficult to spot as it is often hidden from view.
Generally the post cranial skeleton varies from group to group. Differences are considered to relate to type of feeding habits. Cervical vertebrae are shortened at the front, some fused together allowing the neck limited movement. Ribs are delicate in build - stranded whales' ribs are not able to support the mammals weight. Brains are large compared to body size and blood supply are through vessels associated with the spinal cord, the rete mirabile.