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Shark Species ID: Great Hammerhead Shark by Namyr Shark Species ID: Great Hammerhead Shark by Namyr
Scientific Name: Sphyrna mokarran
Common Name: Great Hammerhead Shark, Oceanic Hammerhead, and Flat Hammerhead.

Distribution and Habitat: The Great Hammerhead is a tropical and subtropical species that ranges from inshore shallow waters less than a few feet deep to around 80 m (230 feet) of depth offshore. Great Hammerheads favor drop offs near continental shelves as well as lagoons, coral reefs, and deep drop offs near islands. The Great Hammerhead is a very migratory species and travels great distances across open oceans for thousands of miles, often with the accompaniment of schools of pilot fish. Great Hammerheads can be found throughout the Atlantic, Gulf of Mexico, the Caribbean, Mediterranean, Indian Ocean, Pacific Ocean Polynesian islands, Australia, Coastal North and South America.

Anatomy and Appearance: The most notable distinguishing attribute of the Great Hammerhead is its uniquely expanded cephalofoil (head). This cephalofoil is the common attribute of all the Hammerhead shark species such as the: Smooth Hammerhead, Scalloped Hammerhead, Scalloped Bonnethead, Winghead Shark, Scoophead Shark, Whitefin Hammerhead, Bonnethead Shark, Carolina Hammerhead Shark, and the Smalleye/Golden Hammerhead. The average great hammerhead measures up to 3.5 m (11.5 ft) long and weighs over 230 kg (500 lb). The longest great hammerhead on record was 6.1 m (20 ft). The first dorsal fin of the Great Hammerhead is very distinctive as it is very tall and almost sickle shaped. The rest of its fins including its second dorsal, anal fin, caudal fin, and pectorals are all extremely large in relation to other shark species and are indicative of its nomadic migratory nature. The Great Hammerheads coloration can range from dark grey, to brown, to shades of mottled green which then shift into a faded white or creamy yellow ventral belly.

Diet, Hunting and Feeding Behavior: The Great Hammerhead is a solitary hunter, although has been known to spend much of its time around other reef shark species while hunting. However the Great Hammerhead is given a wide berth by other marine predators and is the undisputed king of the coral reef. Young Great Hammerheads are preyed upon by other large shark species such as the Bull Shark and Tiger Shark, but as a mature adult the Great Hammerhead has no natural predators. Its most common feeding times are concentrated during dusk and dawn. The Great Hammerhead hunts by swinging its great head (covered with electromagnetic receptors) across the bottom of the sea floor which alerts it to fish or rays hiding beneath the sand, this strategy coupled with their keen sense of smell makes the Great Hammerhead a formidable predator of the reef. The Great Hammerhead is known to actively hunt and prey upon the following: Bony fishes, crabs, lobsters, squids, octopus, and other sharks including smooth-hound sharks, grey reef sharks, and even young of their own kind. By far the favored prey of the Great Hammerhead are skates and rays. They seem especially fond of stingrays and have been caught quite commonly with sting ray tail barbs still embedded in their mouth and heads. These barbs however do not seem to dissuade the sharks appetite and seems to cause only a small amount of irritation unless embedded in a vital organ.

Note: This image is a stock image taken from online sources, this is not Namyr copyrighted work.
Link: bushwarriors.org.s130414.grids…
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:iconthemasterarchiver:
TheMasterArchiver Featured By Owner Mar 10, 2014
How does it tell what's directly infant of it? I would imagine that would be a blind spot fir the shark.
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:iconnamyr:
Namyr Featured By Owner Mar 10, 2014  Professional Traditional Artist
Sharks are actually very amazing in that they do not have merely five senses as humans do. They actually have seven documented senses. They have: sight, touch, smell, sound, and taste like us, but also have the ampullae of lorenzini (small pores found around the mouth, head, and snout) which are a connected to jelly filled bulbs which lead to several thousand nerve endings. These pores are receptive of electromagnetic pulses which radiate from muscle movements of virtually every mobile organism. Once the pulse has reached a pore, it travels into the jelly filled bulb and hits the nerve ending. These nerve endings then send the message of movement to the brain and alert the shark where the movement is located. The ampullae of lorenzini allows the shark to "see via electromagnetic pulses" even in complete darkness or in blind spots. The seventh sense of a shark is its lateral line. This line is found near the ampullae of lorenzini near the head and reaches along the horizontal middle of the sides of the shark's body. This line is used to detect pressure changes and vibrations in the water from currents or movements generated by other organisms. This system is made up of sub dermal canals which are connected to pores in the skin. Within these canals are neuromasts which are like tiny hair like nerve clusters. When these clusters are activated by movement in the water they act as a target location system and allow the shark to "feel" the movements of the water. This coupled with its electromagnetic reception and the common "five senses" allow sharks to detect every movement and activity within their aquatic environment.
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:iconthemasterarchiver:
TheMasterArchiver Featured By Owner Mar 11, 2014
So a shark can 'see' even in pitch black, well more or less where the prey is. Interesting. So if one was perfectly still they are invisible to the sharks 7th sense?

But when adding the other 5 no wider sharks are considered the perfect predator!
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:iconnamyr:
Namyr Featured By Owner Mar 11, 2014  Professional Traditional Artist
Yes, they do not need the light to see. Which makes sense if you think about it since some sharks live at great depths with little to no light. But no, not even if one was perfectly motionless would they be invisible. The electromagnetic fields that radiation from the body are not just concentrated within large muscle movement like the limbs. Even the heart emits a small signal by simply beating which a shark can detect. In fact that's how they think Hammerheads find fish and rays hidden in deep sand. Thats also why some shark specialists say it is important in a shark encounter to try and control and relax ones heart/ movements. A shark is more attracted to a rapid uneven heartbeat because that is the kind of vibrations they feel when they get close to prey. In this way sharks can sense minute changes in another organism and can even identify their behavior (IE sensing fear in something).

In my work I go by one very sound rule. Do not act like prey if you do not wish to be seen as prey. This means no erratic behavior, no sudden movements, no panic, no pounding heartbeat, just nice slow strong movements and acting as though you are just another large predator with little concern for the shark. On the inside however you always keep an eye on the animal your working with.
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:iconthemasterarchiver:
TheMasterArchiver Featured By Owner Mar 11, 2014
Hm interesting but if I'm honest, I I was ever in the middle of the ocean and saw a large shark I would freak out a bit. I mean I know what to do to not get attack (mostly) But still the fact that there is a large predator so close can be "a bit" unnerving.
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:iconnamyr:
Namyr Featured By Owner Mar 11, 2014  Professional Traditional Artist
Thats a completely normal and natural biological reaction. No one in impervious to not being "afraid" of that type of situation. Being in the ocean or water where we are not able to move quickly or see well or fight off a potential predator is frightening. But luckily sharks are usually quite leery of humans and will avoid our presence. They are naturally curious but very very cautious animals which can work very well in our favor if we know how to behave. Being stranded at sea with a large shark is no fun however and that would freak me out to. lol.
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:iconthemasterarchiver:
TheMasterArchiver Featured By Owner Mar 11, 2014
Well I'm sure you have been up close to a live several times, but it so it's actually nice to know even experienced people can be unnerved.
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:iconnamyr:
Namyr Featured By Owner Mar 12, 2014  Professional Traditional Artist
Ultimately its a large predator, and although I find them very beautiful, they should always be respected for what they are and what they are capable of.
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