• Sharks are fearsome looking sea creatures.shark 2 image by cherie from Fotolia.com
  
  Sharks are sea creatures found in all the world's oceans, according to the National Parks Conservation Association. There are more than 350 known species of sharks, and although they have a reputation for being vicious man-eaters, only 32 species are known to have attacked humans. One of the most distinctive features of sharks, made popular by the 1975 film, "Jaws," is the dorsal fin. Most sharks have a variety of fin types.
  
  

Dorsal fin

• The fin many people immediately associate with sharks is the distinctive dorsal fin, which may break the surface of the water as the shark swims near the surface. Some sharks have two dorsal fins. The first dorsal fin is the larger of the two and typically located about mid-point on the shark's back, according to the Florida Museum of Natural History. The second dorsal fin, when present, is located closer to the shark's tail. The dorsal fins provide stability while the shark is swimming, and help to prevent the shark from inadvertently rolling over.
  
  

Caudal fin

• The shark's caudal fin is sometimes referred to as its tail fin. The caudal fin is typically composed of an upper lobe and a lower lobe, with the upper lobe usually being the larger of the two. Sharks use the caudal fin for forward thrust when swimming. Some sharks have upper and lower caudal fin lobes that are nearly equal in length, which provides them with exceptional thrust, making them quite fast in the water.
  
  

Pectoral fin

• Sharks have a pair of pectoral fins located behind their heads on their lower front end, below or behind their gill slits, according to the San Diego Natural History Museum. Sharks use their pectoral fins to provide a counterbalance to the force generated by their caudal fins. The pectoral fins provide lift and stability. They are also useful for maneuvering and turning while swimming.