世界上最大的鯊魚是鯨鯊，它是一種長 13.5 公尺的溫和食浮游生物巨鯊。但與大白鯊的史前時代祖先-巨齒鯊相比，鯨鯊就相形失色了。巨齒鯊的牙齒就有 6 吋，而且它的身長超過現今的雙層巴士車身，差不多就跟現在的抹香鯨一樣大。你應該慶幸我們在現代的水域裡(應該)不會再巧遇他們啦！
“Jumping the Shark” 這個詞指的是有些事情跨越了理智線，進入了瘋狂的境界。
這個俚語源自於影集 Happy Days 中的主角 Fonz，就如同 Fonz 當時在有鯊魚的水池滑水跳過一尾鯊魚一樣瘋狂。鯊魚攻擊人的新聞得到了很多媒體關注，但事實上，人類每秒就殺死 3 隻鯊魚，一個禮拜就可以殺死 1,848,000 隻這麼多….
Sharks have a never-ending supply of teeth. They regenerate replacement dentition on an inexhaustible toothy conveyor belt... which explains why you see so few shark dentists.
But sharks are not all about teeth, despite the bad press. Filter feeders like the megamouth shark, are mostly big (but harmless) mouths; the winghead shark has a head half the length of its body, and; the thresher sharks have a huge tail (ideal for stunning fish before eating them) that can be the same length as its body.
In many shark species the females have much thicker skin (I know, I know...). It can be twice the thickness of the males' skin and is thought to be an adaptation to endure ferocious bites from the males during sex.
That's not the only remarkable thing about shark skin, which is composed of tiny teeth like scales called 'denticles' which make it rough if you stroke it the wrong way. So rough, in fact, that it used to be used as sandpaper. The advantage is that in the other direction it makes the shark sleek and hydrodynamic. Shark skin leather (called Shagreen) has also been used for practical and ornamental purposes – including on the handles of ninja swords!
The world's biggest shark is the whale shark, a peaceful plankton-munching giant that can be 13.5 metres long. But it was dwarfed by a prehistoric giant shark, Megalodon, which was a pumped up ancestor of today's great white. It had six inch teeth and was much, much bigger, easily overshooting a double-decker bus in length, and possibly about the same size as today's Sperm whales. Think yourselves lucky they are (probably) no longer around.
The world's smallest shark is probably the dwarf lanternshark, which, like other lanternsharks, glows in the dark.
Sharks use electrical senses to find prey, and the oddly-shaped heads of the hammerhead family are used sweep back and forth like a biological metal detector to find lunch lurking on the seabed. They even enjoy munching on stingrays, oblivious to their deadly barbs.
Some sharks lay eggs and some give birth to live young. They usually have relatively few babies (in fish terms) which makes them vulnerable species. Sharks can be pregnant for two whole years before they give birth, which is longer than whales or elephants. A few shark species give birth to just one or two 'pups' at a time, the successful offspring having eaten all their siblings inside the womb beforehand…
The phrase 'Jumping the Shark', meaning when something crossed the line into ridiculousness, originated on an episode of the sit-com Happy Days when lead character, the Fonz, inexplicably jumped over a shark on waterskis.
Shark attacks get lots of media attention, but humans kill an estimated 3 sharks every single second. Over Shark Week alone that will add up to some 1,848,000 sharks …