Sunday, June 03, 2007

Great White Shark: Of "Jaws" fame

Say, ‘Great White shark,’ and you think, Jaws – the Hollywood blockbuster. See Jaws, and your own drops open!

However, 25 years after writing Jaws, the late Peter Benchley had said in a 2000 interview, "I could not posit the situation now that I posited then... I attributed to them a kind of marauding ‘monsterism’ that became what Jaws was. Now we know that sharks do not attack boats. The way they decide what to eat is by biting it."

So, the Great White is safe, right? Certainly not! Just remember, it’s a case of mistaken identity rather than fatal attraction. Sharks are not fond of humans – Ugh! Too bony and lean for their taste. Fatty seals suit their palate best. That's why 75 percent of humans attacked by Great Whites are spat out in the split second after it sinks its teeth into human flesh.

The Great White is not white, except for its underbelly. It’s grey or blue-grey on the dorsal side, thus making it inconspicuous as it patrols the reefs just over the seabed, in coastal areas – favourite spot for snorkeling and scuba diving.

This largest of the flesh eating sharks, has exceptionally strong muscles that allow it to clamp its jaws shut with immense pressure. Not only that – unlike humans, its jaws are not hinged, allowing it to open them very wide to swallow big prey.

But the story doesn’t end with jaws! The triangular teeth are deadly, though only about two inches long, with serrated edges, like that of a bread knife. There’s more – they grow in rows and as the outer ones break or fall off, the inner ones are pushed forward. Now, get a bite of this – it is estimated that during its 40-year life span, the Great White uses up to 30,000 teeth – that’s quite a mouthful, indeed!

It uses its heightened senses for detecting prey: excellent eyesight and acute hearing; hypersensitive hairs down the sides of its body for picking up vibration from prey; nostrils that can smell a drop of blood in 100 liters of water; small pores in the snout that pick up electrical signals from the muscles of living creatures.

Having detected its prey, usually from its vantage point in the murky depths, it torpedoes upward, breaking surface with the prey in its mouth, before it dives back in. Just before impact, the shark rolls back its eyes, exposing the whites, to protect the most vulnerable part from damage due to the impact. Therefore, in effect, it does not see its prey up close.
The shark never chews its food - it swallows in chunks. If the prey is large, the shark turns away after swallowing the first chunk and waits for it to die before returning for another chunk. After a big meal, it may be a month or two before the shark will need to eat another.

Using the two claspers below its tail, the male shark injects sperm into the female. In the uterus, the young sharks not only feed on unfertilized eggs, but also on other embryos. When the mother gives birth, the young sharks are already about 5 ft long and swim straight off – their mother never sees them, except as prey!

Copyright © 2007 Noël Gama
www.noelgama.com

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