Cannibalism in the animal kingdom - Bill Schutt

翻译人员: Christina Wang 校对人员: Lipeng Chen

一个使生命进步的基本法则－－ 繁衍，变化，让强者生存、弱者死亡。

－－查尔斯·达尔文，《物种起源》

In the deserts of the American Southwest,

在美国西南部的沙漠，

spadefoot toad tadpoles hatch in tiny oases.

锄足蟾的蝌蚪在小绿洲孵化而出。

Until they develop into toadlets, they can’t survive outside of water,

在长成小青蛙前， 它们不能在脱水的环境中生存，

but these ponds are transient and quickly evaporate.

但是它们生活的池塘转瞬即逝， 水分很快就蒸发了。

The tadpoles are in a race against the clock

所以这些小蝌蚪需要和时间赛跑，

to grow up before their nurseries disappear.

要赶在池塘中的水分蒸发前长大。

So nearly overnight, some of the brood explode in size.

几乎在一夜之间， 一部分蝌蚪迅速变大。

They use their jack-o-lantern teeth and huge jaw muscles

它们用了自己锋利的牙齿 和巨大的鄂部肌肉

to devour their smaller pond mates.

来吞食身边更小的蝌蚪。

Nourished by this extra fuel,

通过这额外的食物，

they develop quicker, leaving the pond before it can dry out.

它们成长得更迅速， 继而可以在池塘蒸发前离开。

The spadefoot toad is far from the only animal

锄足蟾远不是动物里唯一

to eat members of its own species as a normal part of its life cycle.

把吞食自己同类以生存 作为正常生命周期的一部分。

All of these animals do.

所有这些动物都是。

If that surprises you, you’re in good company.

如果你感到很惊讶，你不是一个人。

Until recently, scientists thought cannibalism

直到最近以前，科学家以为同类相食

was a rare response to starvation or other extreme stress.

是一个很稀有的、面对饥饿 或其它极端压力才产生的反应。

Well-known cannibals,

已知的同类相食者，

like the praying mantis and black widow spider,

如螳螂、黑寡妇蜘蛛

were considered bizarre exceptions.

曾被视为是奇怪的特例。

But now, we know they more or less represent the rule.

但现今，我们知道它们 或多或少代表了普遍现象。

While it may seem counterproductive

同一物种互相捕食 看起来可能对物种不利，

for members of the same species to eat each other,

cannibalism can promote the survival of the species as a whole

但同类相食也可以 帮助整个物种的存活，

by reducing competition,

通过减少竞争，

culling the weak,

消灭弱者，

and bolstering the strong.

让强者更强大。

Some species, like the spadefoot toad,

有些动物，比如锄足蟾，

cannibalize in response to environmental pressures.

是因为环境压力而吞食自己的同类。

Their situation is precarious,

它们的情况很危急，

but cannibalism for them isn’t a last-ditch attempt to avoid starvation.

但对于它们来说，同类相食并不是 为了避免饥荒的孤注一掷。

Rather, it’s a way to more quickly outgrow a stage

同类相食是更快的长大，跳出一个

where they’re especially vulnerable to predation

它们很容易被捕食，或被 危险的环境条件影响的阶段。

or dangerous environmental conditions.

Other species, including many fish,

其它种族，包括很多鱼类，

indiscriminately cannibalize each other during foraging behavior.

觅食中会无差别的捕食同类。

Fish produce large numbers of tiny young,

鱼类生产大量的、个体小的幼体，

and adults exhibit about as much individual recognition of their offspring

且成年的鱼识别它们自己的后代

as humans do for a handful of raisins.

就和我们识别一把葡萄干一样差劲。

Fish eggs, larvae, and juveniles are easily available, nutrient-rich meals,

鱼卵和幼鱼是 容易获得、营养丰富的一餐，

and with thousands of eggs in a clutch,

且鱼有着上千个鱼卵，

plenty are still available to hatch after the adults have snacked.

成年的鱼就算吃一部分 也还剩很多可以孵化。

Baby fish aren’t just at risk of being cannibalized by adults—

幼鱼不只会被同类里成年的鱼吃掉，

siblings eat each other too.

兄弟姐妹也会互相捕食。

Sand tiger shark eggs develop and hatch

沙虎鲨的卵

会在不同时间段 在母亲的输卵管里发育和孵化。

inside their mother’s oviducts at different times.

When the hatchlings run out of yolk from their own eggs,

当幼体用光了自己卵中的卵黄，

they eat the other eggs and hatchlings

它们就会吃掉其它卵和幼体

until one baby shark from each oviduct remains.

直到每个输卵管里 只剩下一个小鲨鱼。

When they emerge, the young sharks are well-nourished, experienced predators

出生时，剩下的小鲨鱼就有了 充足的营养和丰富的捕食经验

who stand a better chance of surviving.

所以更容易存活下来。

Even when they aren’t consumed for nutrition,

即便有时不是为了营养，

young animals are especially vulnerable to cannibalism.

幼年的动物也很容易被同类相食。

Hamsters,

仓鼠，

rats,

老鼠，

and other rodent mothers

和其它啮齿动物的母亲

will eat some of their young if they’re sick,

会吃掉一部分自己的幼鼠 如果它们生了病，

dead,

死掉了，

or simply too numerous to feed.

或者只是她们无法喂养太多幼鼠。

In other mammals, including bears and lions,

其它动物中，包括熊和狮子，

males will kill offspring sired by another.

雄性会杀死其它雄性的后代。

That’s because childless females become receptive to mating more quickly

这是因为没有幼崽的雌性 比她们在抚养幼崽的时候容易

than if they were caring for a cub.

更容易继续交配。

Rather than waste nutritious meat, the males then eat the dead cubs.

为了不浪费营养丰富的肉， 雄性会吃掉死去的幼崽。

Meanwhile, cannibalism is less common in birds than in other groups,

同类相食在鸟类中更少见一些，

but certain species will eat diseased or dead hatchlings

不过某些鸟也会吃生病或死掉的幼雏

as a way of disposing of the bodies before they can attract maggots.

来处理掉尸体，避免吸引蛆虫。

When adults eat each other, males are cannibalized more often than females,

对于成虫间的互相捕食， 雄性比雌性更容易被吃掉，

usually during mating and generally because they’re smaller.

一般在配偶期， 原因通常是雄性体型更小。

Male Australian redback spiders mate with much larger females.

比如，雄性澳洲红背蜘蛛 会和体型大很多的雌性交配。

Rather than scrambling away after mating, the tiny male does a somersault,

交配后，小小的雄性不会马上离开， 而是翻个跟头，

bringing his abdomen into contact with his mate’s mouthparts.

把自己的腹部移到配偶的口器旁边。

The female showers him with enzyme-rich gut juice and consumes his abdomen.

接下来，雌性用含有酶的消化液 吃掉雄性的腹部。

Males not killed in the initial mating crawl back into the fray,

没有被第一次交配 直接杀死的雄性会回来，

often half-eaten,

一半已被吃掉的情况下，

to mate again, after which they’re dispatched to the spider pantry.

继续交配，然后成为雌性蜘蛛的食物。

So not only does the male provide the female with his sperm,

这样，雄性不只给雌性提供了精子，

but he also provides her with a nutritious meal

他还提供了一顿营养丰富的晚餐

to better ensure that she’ll survive to pass on his genes.

来确保雌性可以生存， 把自己的基因传下去。

All in all, it’s clear that cannibalism is

总的来说，同类相食

as much a part of life in the animal kingdom

无疑是动物王国生命中的一部分，

as other, better-recognized behaviors.

和其它我们更了解的行为一样重要。

As we sink our teeth into the evidence of cannibalism in nature,

当我们继续深入探索 自然界中同类相食的证据，

we might ask ourselves,

我们也应该问问自己，

what else have we missed by applying human standards to the natural world?

还有什么东西，是因为我们把 人类的标准用在自然界而被我们漏掉？

有兴趣了解更多吗？

我们强烈推荐本视频作者的书 “Cannibalism: A Perfectly Natural History”