57 Jaws

Of all the fish in the ocean, sharks are the greediest eaters and killers. They suffer from continual hunger. Almost as soon as they have eaten, they are on the prowl for more food. Sharks have been described as eating machines, and indeed they are perfectly designed for that activity. They are powerful swimmers, with smooth, well-muscled, streamlined bodies.

But the most remarkable part of a shark is its mouth—a wide gash lined with rows of jagged teeth. When a shark attacks, it opens its mouth wide until its teeth can stab straight into the body of its victim. The teeth slice like razors as the shark twists and rolls its body to tear off a chunk of food. New teeth are constantly being formed and moving forward to take the place of those lost during the shark’s violent feeding activities. Even very old sharks have razor-sharp teeth.

The largest and most fearsome of the species is the great white shark. Its average length is between fourteen and sixteen feet. A few great whites may reach well over thirty feet in length. The longest ever recorded was a thirty-seven-footer, a truly monstrous fish. The great white lives in the tropical seas and sometimes along the southern coast of the United States.

# 57 大白鯊

在海洋里的所有鱼类中，鲨鱼是最贪婪的捕食者和杀手。它们饱受持续饥饿的困扰，刚吃完东西，几乎立刻就会四处搜寻更多食物。鲨鱼被描述为“进食机器”，而它们的身体构造确实完美适配这项活动——它们是强大的游泳健将，有着光滑、肌肉发达、流线型的身躯。

但鲨鱼最引人注目的部位是它的嘴——一道宽大的裂口，内侧排列着一排排锯齿状的牙齿。当鲨鱼发起攻击时，它会把嘴张得很大，直到牙齿能直接刺入猎物的身体。在鲨鱼扭动翻滚身体撕扯食物块时，这些牙齿会像剃刀一样切割。新的牙齿会不断生成并向前移动，替代那些在鲨鱼激烈的进食活动中脱落的牙齿。即便是很老的鲨鱼，牙齿依然锋利如剃刀。

这类物种中体型最大、最可怕的是大白鲨。它的平均体长在14到16英尺之间，有少数大白鲨的体长能远超30英尺。有记录以来最长的大白鲨长达37英尺，是真正的巨型鱼类。大白鲨生活在热带海域，有时也会出现在美国的南部海岸附近。