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UNDERWATER GUIDE TO MARINE LIFE 



common both at the surface and on the bottom. The htters are large, averaging 

 thirty-five and recorded from six to fifty-two. Gestation may take one year. It is 

 ovoviviparous. 



HAMMERHEADS: Family Sphyrnidae 



The widely expanded and flattened head serves to separate these sharks from 

 the otherwise similar requiem sharks. The eyes and nostrils are at or near the 

 ends of the head's extensions. Supposedly, the head, acting like a forward 

 rudder, gives these sharks greater maneuverability than other sharks. The very 

 large and wide-set nostrils are highlv efficient. These sharks are usuallv among 

 the first to arrive when blood is in the water. Hammerheads are found in all 

 warm temperate and tropical seas. 



hammerhead: Sphyrna zygaena 



Size: Matures at 7 to 8 feet. Averages 8 to 11 feet. Reaches 15 feet. 



Weight: 900 pounds at 12 feet. 



Distribution: All tropical and subtropical seas. North to Cape Hatteras (rarely 

 to Cape Cod) and southern California. 



Identification: Slate to brownish gray in color. 



Habits: This is a strong-swimming, voracious, active, surface shark, found at 

 sea or inshore or even in tidal, brackish waters. Like many other sharks, it often 

 basks at the surface with its caudal and dorsal fins protruding. Hammerheads 

 have a definite liking for sting rav meat. They will also eat fishes of various 

 kinds and other sharks as well. Great numbers of sting ray and catfish spines 

 have been found in the heads, jaws, and bodies of hammerheads, apparently 

 causing no discomfort to the shark. This shark is known to be dangerous to 

 men even though the teeth are rather small. The northerly migration of schools 

 of hammerheads in the summer consists mainly of small, 6-foot sharks. They 

 are viviparous, bearing up to thirty-seven young. 



Similar Sfecies: Sfhyrna zygaena is merely one of three very similar hammer- 

 heads. The great hammerhead, Sfhyrna tudes, is the largest of these. It reaches 



eONNCT 



Fig. 67 . Hammerhead shark and bonnet shark. 



