自我保护之冻结的一瞬间

Suppose you are an animal. Well, actually, you are an animal, but suppose you’re another kind of animal, maybe something small that might make a tasty snack for a larger predator. You’re walking along one day when you see a big dog. What do you do? 假设你是一只动物。额，你其实本来就是一只动物。但假设你是另外一种动物，也许是一种可以被食肉动物当成可口点心的小动物。如果有一天你在独自散步时看到一条大狗，你会怎么办？

Well, depending on what kind of animal you are, you have different options. A skunk can spray a noxious liquid that will repel predators, a cat can make its hair stand on end so that it seems larger than it is, or some animals, such as opossums, may pretend to be dead already. 好吧，这取决于你是哪种动物，你有不同的选择。一只臭鼬可以释放毒液击退捕食者，一只猫可以让它的毛发倒竖起来，让它看起来比往常更大，还有一些动物，比如负鼠，也许早已装死躺在地上了。

There’s another strategy all these animals have, though. You’ve seen it before, but maybe never thought about it. They can freeze. 其实这些动物还有另外一条策略，虽然你可能以前见过，但也许你从来没想到过。它们可以冻结。

When a squirrel or a rabbit or a chipmunk freezes, it can remain almost entirely motionless for minutes at a time. Try it yourself. Whatever position you’re in right now, move nothing at all for the next minute. It’s not so easy! 当一只松鼠，兔子或花栗鼠冻结时，它可以一次保持完全静止不动达数分钟之久。你自己试试。不管你现在是什么姿势，在下一分钟内保持一动也不动。这可没那么简单！

The reason an ability to freeze works as a defense is that a predator’s attack behavior may actually be triggered by motion. A frog, for example, will literally starve to death in a box full of dead flies. Pass one of those flies in front of its eyes on a little string, though, and it will automatically gulp it down. 冻结能作为一种防御的手段，其原因在于一个食肉动物的攻击行为可能只是由运动而引起。举例来说，一只青蛙，会在装满死苍蝇的盒子里活活饿死。用一根线绑住其中一只从它眼前经过，它就会不假思索的把苍蝇吞下去。

The response to freeze is completely hard-wired, so freezing shows us something about both predator and prey. Evolution has caused the freeze strategy to come into existence precisely because it fits in with the way the visual systems of predators operate. 对冻结的反应是动物与生俱来的，所以冻结给我们展现的是捕食者和被捕食者双方的特性。进化已使得冻结策略应运而生，因为它适应了捕食者视觉系统的运转方式。