Fact Sheet: Smooth Hammerhead Shark TheSmooth Hammerhead Shark (Sphyrna zygaena). © Innerspace Vissions / Shark Foundation The biology of the smooth hammerhead shark (Sphyrna zygaena) The typical feature of smooth hammerhead sharks (Sphyrna zygaena) which distinguishes it from other large hammerhead species, is the shape of its cephalophoil, or head. A bird's-eye view of the head shows that it resembles more of an ax rather than the classic hammer, and lacks the usual central indentation. Description Smooth hammerhead sharks are large sharks with a rather steeply ascending first dorsal fin which tapers into a sickle form at the back. Unlike the brownish color of many other hammerhead shark species, its primary color on the top is olive green or dark gray-brown and white underneath. Their pectoral fins have black tips at the underside. Size and Age Adults of this species can reach lengths ranging between 370 and 400 cm. Their maximum age has not yet been examined in detail but it is presumed that they can reach the age of 20 or older, as do many other large species of the order Sphyrna. Diet The smooth hammerhead sharks feeds on different species of fish, small sharks and rays. However, spineless fish such as crawfish, squid and other similar fish have also been found in analyses of stomach contents. This species is also known to eat carrion. Reproduction These sharks are viviparous and have a yolk sac placenta. The litter size ranges between 29 and 37 pups, the length of the pups at birth between 50 and 60 cm. Males and females become sexually mature when they reach an approximate length of 210 to 240 cm. Distribution The species is found worldwide, including along the Continental Shelf, but it prefers moderate water temperatures. Despite its preference for more shallow waters over the Continental Shelf it has also been sighted around Hawaii and the Galapagos. Of all hammerhead shark species the smooth hammerhead can best tolerate colder waters. Behavior Although smooth hammerheads are the most frequently seen species of hammerheads, their behavior has not yet been studied in detail. It is known that they prefer to stay in very shallow waters where they are often seen in larger schools. Encounters with humansn Although this species is said to have been involved in accidents, we must be careful about putting too much weight on this statement, considering that in each case their identification was only based on knowledge of their distribution. Endangerment NAccording to information from the World Conservation Union (IUCN) there is only a minimum risk for the populations of smooth hammerhead sharks May be published only by indicating the source: Shark Info / Dr. Erich K. Ritter

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