The shovel or bonnet-shaped head is a distinguishing characteristic of this species, making it easy to identify. The eyes of the bonnethead shark are located at the ends of the evenly rounded lobes of the flattened head, increasing the field of vision. When the bonnethead swims, the head rolls from side to side. The arched mouth is located ventrally. The body is moderately compact and lacks a mid-dorsal ridge. The high first dorsal fin originates just behind the base of the pectoral fins. The second dorsal fin is slightly less than half as long as the base of the first dorsal fin with a slender free rear corner. The pectoral fins are short and the anal fin has only a slight indentation. The caudal fin has a nearly straight upper margin with a lower lobe about one third as long as the upper lobe with a nearly straight rear edge. Coloration of the bonnethead ranges from gray to gray-brown, occasionally with a green tint. Dark spots are sometimes seen on the sides of the body. Viewed from the side, the color changes from top to bottom to a lighter gray and then white on the underside. There are no conspicuous markings on the fins.
Bonnetheads reside on continental and insular shelves, over reefs, estuaries and in shallow bays from depths of 32 to 262 feet. They usually occur in small schools of up to 15 individuals, however, during migration events they are seen in groups of hundreds or thousands. As spawning time approaches, bonnetheads tend to group by gender. During pupping season, females predominate in shallow waters where they give birth. Bonnetheads travel long distances everyday, following changes in the water temperature. As a result, the bonnethead is found closer to the equator during the winter, moving back to higher latitudes during the summer.