Hammerhead Sharks

0

Hammerhead Sharks are amazing to see & even more so when schooling.

This shark’s name comes from the unusual shape of its head, an amazing piece of anatomy built to maximize the fish’s ability to find its favorite meal: stingrays. A hammerhead shark uses its wide head to trap stingrays by pinning them to the seafloor. The shark’s eye placement, on each end of its very wide head, allows it to scan more area more quickly than other sharks can. The hammerhead shark also has special sensors across its head that helps it scan for food in the ocean. Living creatures’ bodies give off electrical signals, which are picked up by sensors on the prowling hammerhead. Besides their distinctively shaped head, Hammerhead sharks also have the ability to turn very quickly when they are hunting and so capture their prey more easily.

hammerhead-shark_undersea_huter

The proper name for its hammer-like visage is cephalofoil. These cephalofoils are thought to help the hammerheads in a number of ways. Firstly their eyes are spread far apart to give it a wider visual array. Secondly, the nostrils are long and spread out across the front of the cephalofoil meaning it can probably smell in stereo which gives it an awesome head start when sniffing out supper. Each nostril is longer than its entire mouth. Thirdly, sharks are electrosensitive and can detect the minute electrical signals that pump out of prey items’ muscles. This enlarged cephalofoil is rich with electrosensitive cells, called ampullae of Lorenzini, making it incredibly sensitive to the whereabouts of dinner. Lastly, the lateral line in hammerhead sharks runs along the length of its head. The lateral line is a mechanoreceptive structure that detects pressure waves in the water around the shark. This enables it to detect anything moving in its vicinity just from the swell and ebb of the water around it.

All hammerhead sharks are coastal swimmers, swimming out into ocean depths no deeper than 300 m. They are distributed over circumtropical water, clinging to the coasts of nearly all continents within warmer waters. Along the western Atlantic they flow from North Carolina down to Uruguay, from Baja California down to Peru along the eastern Pacific, all along the western Pacific and also inhabit the Mediterranean Sea region and the Indian Ocean region.

Hammerhead sharks hunt alone, and can find stingrays that hide under the sand on the seafloor. Hammerheads also eat bony fishes, crabs, squid, lobsters, and other sea creatures. The upper sides of these fish are grayish-brown or olive-green and they have white bellies. They have very impressive triangular, serrated teeth—like the edge of a saw’s blade. Hammerhead mouths are on the underside of their heads.

There are nine variants of hammerhead shark and an additional species that is similar.

The Winghead shark, is found in the tropical western Indo-Pacific, from the Persian Gulf eastward across South and Southeast Asia to New Guinea and northern Queensland. Its range extends as far north as Taiwan and as far south as the Montebello Islands off Western Australia. It has larger cephalofoils than any other hammerhead sharks, though they are smaller than the largest of the hammerhead sharks, the Great Hammerhead. The other hammerhead species are the Bonnethead, the Great Hammerhead, the Scalloped hammerhead, Carolina hammerhead, Scoophead shark, Smalleye hammerhead, Smooth hammerhead and the Whitefin hammerhead.

On an average basis, the hammerhead shark ranges from 1m to 6m+, with the largest being the Great Hammerhead. They can range in weight from 3 to 550 kg. The hammerhead family ranges from dark brown to grey on their dorsal side and have a grey or white belly, sometimes even olive in color which performs as a sort of camouflage while hunting. Previous to scientific research, it was thought that the cephalofoils were used to enhance poor vision in the shark but studies have shown that not only do the hammerheads have excellent vision but also possess the ability to turn quickly and sharply due to the the aided maneuverability the cephalofoils provide. It has been considered that the hammerhead evolved the cephalofoils due to the unusually small mouths they have.

Like all sharks, hammerheads have electroreceptory sensory pores called ampullae of Lorenzini, allowing them to sense electromagnetic pulses from prey, making them one of the most deadly predators in the ocean. The shape of their mallet like head also allows them to scan wider areas of the ocean floor in search of prey, acting almost like a radar.

The hammerhead is an active hunter rather than a scavenger, choosing to hunt around dusk when the sunlight works to the advantage of the shark. The hammerhead consumes invertebrates, jellyfish, crabs and octopi, as well as other bony fish. While they will eat nearly any animal in the ocean, the hammerhead seems to prefer the stingray. There have been records indicating the hammerhead also performs cannibalism among their own or other family species.

Great Hammerhead sharks tend to be solitary swimmers while Scolloped Hammerheads tend to be schooling sharks, with schools sometimes numbering in the hundreds.

Unlike many fish, hammerhead sharks do not lay eggs. A female gives birth to live young. One litter can range from six to about 50 pups. When a hammerhead pup is born, its head is more rounded than its parents’.

There have been very few recorded attacks, but most Hammerhead shark species are thought to be at risk.  Since Hammerheads often are swimming close to the surface, they are prime targets for fishermen that are looking for shark fins.  Humans are it’s # 1 threat.

All content provided on the “Scuba Diving Resource”  website is for informational purposes only. Any comments, opinions that may be found here at Scuba Diving Resource are the express opinions and or the property of their individual authors.
Scuba Diving Resource makes no representations as to the accuracy or completeness of any information on this site or found by following any link on this site. Please note that regulations and information can change at any time.

June 29, 2016 |

Leave a Reply

Powered By DesignThisWebsite.com
Skip to toolbar