Marine Biology

Great White Sharks



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The Great White Shark. Carcharodon carcharias. Jaws. He is the legendary great eater of the oceanic deep and the very name conjures up images of a mindless flesh-tearing killer. Second only to the Orca in its position to the top of the food chain, the great white is the largest predatory fish in the ocean, reaching lengths of up to 20 feet. And while an Orca can easily take out a great white, and they tend to eat the same things in the same areas, there are very few reports of either one attacking the other. Dolphins have also been known to kill a great white by mobbing it and essentially ramming it to death, however, the great white will generally try to steer clear of a pod of dolphins and only go after solitary or sick ones.

Great whites are found in almost all coastal and offshore regions that maintain a water temperature of 54 to 75 degrees Fahrenheit, and thus their feeding habits are based on the fish found in these areas. Great whites eat just about everything in the ocean, including things they can't even digest, except for sea otters and penguins. Larger great whites, those over 11 feet, have a stronger appetite for mammals like porpoises and whales due to their need for the fat content that provides them with a high-energy meal.

Their propensity for sucking down things like license plates and other random items dumped in the ocean by humans has given them a reputation of being an indiscriminate eating machine. While their attacks are indeed ferocious they are actually choreographed ambush attacks. Great whites sense prey from far away using their highly advanced lateral line, the sense organ that detects movement in the water. As the shark closes in he turns to hearing and smelling. Once the shark is directly upon it's next meal it uses sight to determine if he's found food.

Great whites do their hunting early in the morning within the first 2 hours of sunrise. As you can imagine taking an early morning dip in waters known to inhabit great whites could be a deadly mistake. The hunting style depends on the prey. When attacking Cape fur seals the great white will come up from the deep at lightning fast speeds and often launch itself and the prey out of the water. Northern fur seals are larger and potentially dangerous so the great white will sneak up behind and bite the hindquarters, thereby immobilizing the fur seal. The great white will then wait as his breakfast bleeds to death before devouring it. Harbour seals are grabbed off the water's surface and pulled down into the depths until they stop struggling. Dolphins and porpoises have echolocation so the great white will do all it can not to be detected.

While it may appear that great whites attack with reckless abandon, their hunting and eating skills are quite planned and highly advanced. It's true that some things end up in their belly that probably shouldn't, however they do have a menu of regular prey. Great white shark attacks on humans do happen, however it's often a case of mistaken identity and low visibility, in which the shark believe a sunbather is a seal. The majority of attacks are a result of test biting where the shark mouths whatever it sees to determine whether or not it's food. Fatalities are usually the result of the person's blood loss rather than the shark consuming them. In general, great whites do not consider humans to be on their menu!

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