Bonnethead most negatively buoyant of marine vertebrates. The shark feeds primarily on crustaceans, consisting mostly of blue crabs, but also shrimp, mollusks, and small fish. Its feeding behavior involves swimming across the seafloor, moving its head in arc patterns like a metal detector, looking for minute electromagnetic disturbances produced by crabs and other creatures hiding in the sediment. Upon discovery, it sharply turns around and bites into the sediment where the disturbance was detected. If a crab is caught, the bonnethead shark uses its teeth to grind its carapace and then uses suction to swallow. To accommodate the many types of
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