There is no known sexual dimorphism. The humpback dolphin is known for its unusual dorsal fin. A second, smaller hump, exists on the dorsal side just prior to the fluke. Sousa teuszii 's pectoral fins are under 30 cm in length, and their flukes have a width of approximately 45 cm. The coloration of Sousa teuszii darkens as individuals age.
Younger dolphins are a light cream color, and as they get older, they become more gray.
Atlantic humpbacked dophins have 26 to 31 pairs of homodont, peg-like teeth in each jaw. They also have fewer vertebrae than their sister species. Their diet consists of fish such as sardines and mullet which they herd towards land. By herding their prey close to land, they create a situation in which there is little opportunity for escape. They may also feed upon some small crustaceans.