Bonnethead fish control pitching (up-and-down motion of the body), yawing (the side-to-side motion), and rolling. Most hammerhead sharks do not yaw or roll and achieve pitch using their cephalofoils. The smaller cephalofoil of a bonnethead shark is not as successful, so they have to rely on the combination of cephalofoils and their large pectoral fins for most of their motility. Compared to other hammerheads, bonnethead sharks have larger and more developed pectoral fins and are the only species of hammerhead to actively use pectoral fins for swimming. Using data from mtDNA analysis, scientist have found that evolution of hammerhead sharks probably
Scalloped bonnethead mallet-shaped head, called a cephalofoil, is moderately wide (24-29% of total length) and elongated lengthwise. The front margin is broadly arched, with shallow lateral and medial indentations, and no prenarial grooves. The mouth is small and strongly arched. The anal fin is long and has a nearly straight rear margin. Its coloration is gray above and white below, with no prominent fin markings. The similar scoophead ("Sphyrna media") can be distinguished by a shorter snout, a broader mouth, and a deeply concave anal fin margin. Like other hammerheads, the scalloped bonnethead is viviparous, with presumably two pups per litter. The