Shark Facts

 
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Guadalupe Great White; Photo Luke Cresswell

Carcharadon Carcarias, the great white… Up to 20 ft long, weighing over 2 tons, it’s the largest of the carnivorous sharks.

Its senses have developed to an amazing degree: it has excellent eyesight, and sense of smell, but can also detect vibrations in the water along its entire body. It can even detect the electricity generated by living things…

It’s ancient lineage makes it quite distinct from bony fish like tuna, cod or salmon, in that it doesn’t have a bone in its body. Instead, it has a soft, cartilaginous skeleton; unlike bony fish, it doesn’t have a “swim bladder”, instead its oil-rich liver aids buoyancy.

With the combination of  a soft skeleton and formidable tail muscles, it is powerful and fast…

Its skin, covered in tiny teeth like scales called denticles, can be rough as sandpaper……yet silky smooth from head to tail. It’s skin also aids its speed in the water: it has elastic properties enabling it to contract and expand, propelling fast through the water as it flexes its tail muscles.

food chain

Great Whites are (almost) top of the food chain: still frame by Frima FX

It has even evolved a method of storing and releasing heat in its muscles, so although technically not warm blooded per se, it is able to control its body heat relative to the surrounding water. And much like mammals, it gives birth to live pups, already 4 or 5 feet long. Several pups gestate within the mother, who continues to produce infertile eggs which provide the pups sustenance.

Young White Sharks eat fish and rays: their jaws don’t develop the strength they are famous for until they reach maturity, when their speed and power helps them move up the food chain. Their diet changes as they mature, and they switch to larger prey: seals, sea lions and elephant seals, whose blubber contains a store of energy that the sharks cannot resist.

Adult Great Whites need only fear the occasional Orca and the animal at the top of the food chain, mankind… Some Orcas have discovered a knack for turning Great Whites upside down, which immediately sends them into a state of “tonic immobility”, a kind of sleep like trance, lending them totally vulnerable. The Orcas then only eat the sharks highly nutritious liver.