Smooth Hammerhead Shark

Average size between 250 cm and 350 cm, maximum total length about 400 cm. Large hammerhead. Broad and narrow-bladed head with a broadly arched anterior margin and no median indentation. First dorsal fin is moderately falcate with a free rear tip that is in front of the pelvic fins" origins. Origin of the first dorsal fin is over the pectoral fins insertions. Second dorsal fin is low and shorter than the anal fin. Pelvic fins are not falcate. Precaudal pit present. Display dark olive to grey-brown coloration with white ventral surface. Undersides of pectoral fin tips are dusky colored.
 

The only hammerhead shark that occurs in temperate waters. Lives close to shore over the continental and insular shelves as well as offshore, down to depths of 20 m. Very active. Adult smooth hammerheads are either solitary or form small groups. They may come together in great numbers during their annual migrations; schools of over a hundred juveniles under 1.5 m (4.9 ft) long have been observed off the eastern Cape of South Africa, and schools thousands strong have been reported off California. During hot summer weather, they can be seen swimming just below the surface with their dorsal fins exposed. The smooth hammerhead is an active-swimming predator that feeds on bony fishes, rays, sharks (including of its own species), cephalopods, and to a lesser extent crustaceans such as shrimp, crabs, and barnacles. They readily scavenge from fishing lines.

Viviparous: once the young exhaust their supply of yolk, the empty yolk sac is converted into a placental connection through which the mother delivers nourishment. Females bear relatively large litters of 20–50 pups after a gestation period of 10–11 months. Birthing occurs in shallow coastal nurseries, such as Bulls Bay in North Carolina. The pups measure 50–61 cm (20–24 in) long at birth; females reach maturity at 2.7 m (8.9 ft) long and males at 2.1–2.5 m (6.9–8.2 ft) long, depending upon locality.