Hammerhead Sharks Essay -- essays research papers fc

Hammerhead SharksMarine Science/ Per. 1     Sharks argon one of the close feargond ocean animals. They live in oceansacross the world but are about common in tropical waters. There are over triadhundred fifty species of sharks. They can be broadly categorized into thefollowing four groups Squalomorphii, Squatinomorphii, Batoidea, andGaleomorphii. The shark family Sphyrnidae that includes the Hammerheads arepart of the Galeomorphic classification. They are probably the most easilyrecognizable of all the sharks. The Hammerheads are among the strangest lookingsharks. As the name indicates they have a flattened head which resembles thehead of a shape. Their eyes and nostrils are at the ends of the hammer. Thereare many species of Hammerheads. There are eight living species of hammerheads.The following four are the main categories1. Scalloped hammerhead (Sphyrna lewini)-Pectoral fins are tipped with blackthis grey shark. The maximum length is about 12 feet.2. Bon nethead (Spyrna tiburo)-With a head shaped like a shovel the bonnetheadrarely grows more than four feet long. This shark is commonly seen inshore.3. Smooth hammerhead (Sphyrna zygaena)-Bronze with dusky fin tips, it can growto thirteen feet.4. Great hammerhead (Sphyrna mokarran)-Attaining a length of a possible 18 feet,this is the largest and most dangerous of all the hammerheads.     One of the most interesting things about the hammerheads is the uniqueshape of their heads. Ever since scientists started to hold the hammerheadthey have speculated about the use of the hammer. The hammer is a complexstructure and probably executes more than one function. The most importantfunction of the hammer according to scientists is increased electroreceptivearea and its sensory perception. This means that the hammerhead has aremarkable sensory ability to detect the small electrical auras surrounding allliving creatures. Under certain conditions, such as in searching for wou ndedanimals, the electrical activity increases helping the hammerhead to feed. Itis also believed that the hammerhead whitethorn be able to use the Earths magneticfield as a source for navigation. Some hammerheads migrate a lot and may relyon this built in compass sense to guide them in the open ocean. Another use forthe hammer is to enhance maneuverability. The hammer... ...heads go there for mating purposes. Observations in thesesea mounts show that the majority of hammerheads there are young-bearing(prenominal). Thisindicates that its easy for the male to find a mate. However, researchers weresurprised to find that there were many immature female hammerheads at the seamounts. This led them to believe that in addition to reproduction there must beother reasons for coming to the sea mounts. It is believed that the sea mountsserve as navigational centers. Each evening the hammerheads begin a ten tofifteen mile swim away from the mount, always returning by cross or the followingda y. It seems that they spend the night at distant deep water feeding grounds.The young females participate in these long distance swims. The sea mountserves as a navigational center helping them find their way back. The nightlyswim help the young find nutritious intellectual nourishment which helps them in their growth.BibliographyKlimley, Peter, "Hammerhead City", Natural History, Oct. 1995, pp 33-38. Martin,Richard, "Why the Hammerhead?", Sea Frontiers, May-June 1989, pp. 142-145. Moss,Sanford, Sharks, Prentice-Hall, 1984. World Book Encyclopedia, Sharks, WorldBook Inc., 1988.