What crows teach us about death | Kaeli Swift

翻译人员: Nicole Jin 校对人员: psjmz mz

Whether we want to or not, humans spend a great deal of time

无论我们想不想， 人类往往会花很多时间

considering death.

考虑死亡这件事。

And it's possible we've been doing so since shortly after homo sapiens

而且这样的想法很可能 在智人首次在陆地上迁移后不久

first began roaming the landscape.

就已经出现了。

After all, the first intentional human burial

毕竟，据说人类 第一个有意举行的葬礼

is thought to have occurred around 100,000 years ago.

发生在十万年前。

What might those early people have been thinking

早期人类花时间 在地上挖一个洞，

as they took the time to dig into the earth,

把一具尸体放到洞中，

deposit the body

再小心地用土覆盖上去的时候，

and carefully cover it up again?

他们到底在想些什么？

Were they trying to protect it from scavengers

他们是在防止食腐动物破坏尸体，

or stymie the spread of disease?

还是在防止疾病传播？

Were they trying to honor the deceased?

他们在缅怀逝者吗？

Or did they just not want to have to look at a dead body?

还是他们只是不想看到遗体？

Without the advent of a time machine,

在时光机器出现之前，

we may never know for sure what those early people were thinking,

我们可能永远不知道 当时人们是怎么想的，

but one thing we do know is that humans are far from alone

但我们可以肯定的一点是，

in our attention towards the dead.

重视死亡的不止是人类。

Like people, some animals,

跟人类相似，有的动物，

including the corvids, the family of birds

比如柯维鸟科，

that houses the crows, ravens, magpies and jays,

像乌鸦、渡鸦、喜鹊和松鸦，

also seem to pay special attention to their dead.

也很关注它们的死者。

In fact, the rituals of corvids may have acted as the inspiration

其实，柯维鸟家庭的仪式 可能启发了

for our own.

人类自己的仪式。

After all, it was the raven that God sent down

毕竟，是上帝派乌鸦下来教该隐

to teach Cain how to bury his slain brother Abel.

怎么埋葬他过世的弟弟，亚伯的。

But despite this clear recognition by early people that other animals

尽管古人对其他动物处理死者

attend to their dead,

有这种清晰的认知，

it's only fairly recently that science has really turned its attention

但这些现象在最近

towards this phenomenon.

才引起科学的注意。

In fact, a formal name for this field -- comparative thanatology --

实际上，这个学科的正式名称—— “比较死亡学”——

wasn't first introduced until 2016.

直到 2016 年才被引入。

In this growing field, we are beginning to appreciate what a rich place

在这个发展中的领域， 我们开始意识到地球上

the natural world is with respect to how other animals interact with their dead,

不同动物在对待死者 这个主题上的多样性，

and it's in this growing body of knowledge

并且这些逐渐积累的知识

that that time machine to our early ancestors might be possible.

可以让我们对祖先 有更多的了解。

So what are we learning in this growing field?

那么我们在这个领域学到了什么？

Well, right now we can split our understanding into two main groups.

我们可以先把 我们的知识分成两大类。

In the first, we have animals that display stereotyped, predictable behaviors

第一，是那些对死者表现出

towards their dead,

刻板、可预测行为的动物，

and for whom much of what we understand about them

我们对它们的了解大多来自

comes from experimental studies.

实验研究。

This group includes things like the social insects --

这些群体包括社会类昆虫——

bees and ants and termites --

比如蜜蜂、蚂蚁，还有白蚁——

and for all of these animals, colony hygiene is of critical importance,

对所有这些动物来说， 群体卫生至关重要，

and so as a result these animals display rigorous undertaking behaviors

因此，这些动物对死尸表现出了

in response to corpses.

严格的责任行为。

For example, they may physically remove carcasses from the colony.

例如，它们可能会把死尸 从群居中移走，

They may consume them.

也可能吃掉它们。

They may even construct tombs.

甚至会为死去的同伴建造坟墓。

We see similar hygiene-driven responses in some colony-living mammals.

我们在一些生活在聚居区的哺乳动物身上 也看到了类似的卫生驱动反应。

Rats, for example, will reliably bury cage-mates

例如，老鼠会很负责地埋葬

that have been dead for 48 hours.

去世 24 小时的笼中同伴。

In our other group, we have animals that display more variable,

在另一些群体中，动物的行为 则表现得更加多样化，

perhaps more charismatic behaviors,

或者更具魅力，

and for whom much of what we understand about them

我们对它们的了解

comes from anecdotes

多来自科学家

by scientists or other observers.

或其他观察者的趣闻轶事。

This is the animals whose death behaviors

我猜人们对这种动物

I suspect might be more familiar to folks.

对待死者的行为可能更为熟悉。

It includes organisms like elephants,

这包括大象这样的生物，

which are well-known for their attendance to their dead,

它们以悼念死者而闻名，

even in popular culture.

即使在流行文化中。

In fact, they're even known to be attracted

实际上，它们甚至会被

to the bones of their deceased.

死者的尸骨所吸引。

It also includes animals like primates,

这也包括灵长类动物，

which display a wide variety of behaviors around their dead,

它们对死者也表现出了 非常多样化的行为。

from grooming them

从为它们梳毛

to prolonged attention towards them,

到长时间关注它们，

guarding them,

守卫它们，

even the transportation of dead infants.

甚至携带死婴行走。

And that's actually a behavior we've seen in a number of animals,

我们在很多动物身上 都看到过类似的行为，

like the dolphins for example.

比如海豚。

You may remember the story of Tahlequah,

你可能还记得 Tahlequah 的故事，

the orca in the resident J pod in the Puget Sound,

它是普吉特湾 J 族中的 一头逆戟鲸。

who during the summer of 2018

2018 年夏天，

carried her dead calf

它托着她死去的幼崽

for an unprecedented 17 days.

度过了史无前例的 17 天。

Now, a story like that

这样的故事

is both heartbreaking and fascinating,

让人心碎而又着迷，

but it offers far more questions than it does answers.

但它引出的问题远远多于答案。

For example, why did Tahlequah carry her calf

比如，为什么Tahlequah 要携带它死去的幼崽

for such a long period of time?

如此长的时间？

Was she just that stricken with grief?

她是如此伤心吗？

Was she more confused by her unresponsive infant?

她是因为自己的婴儿 不能反应而困惑吗？

Or is this behavior just less rare in orcas

还是说这种行为在逆戟鲸中

than we currently understand it to be?

并不像我们现在 所理解的那样罕见？

But for a variety of reasons,

但因为种种原因，

it's difficult to do the kinds of experimental studies

我们很难在逆戟鲸

in an animal like an orca, or many of these other large mammals,

或其他大型哺乳动物身上进行

that might elucidate those kinds of questions.

这类有可能回答 这些问题的实验研究。

So instead, science is turning to an animal whose behaviors around death

因此，科学把目光转向一种动物，

we've been thinking about since BCE:

我们从公元前就开始思考 它们对待死者的行为：

the crows.

那就是乌鸦。

Like insects and primates,

跟昆虫和灵长类动物类似，

crows also seem to pay special attention to their dead.

乌鸦也对死者特别关注。

Typically, this manifests as the discovering bird alarm calling,

最典型的表现就是 发出鸟类的警鸣，

like you can see in this photo,

和这张照片中的画面类似，

followed by the recruitment of other birds to the area

随后是召唤其他鸟来到这个区域，

to form what we call a mob.

形成了我们所说的“乌合之众”。

But it can be a little different than that too.

但实际场景也可能 跟照片有点不同。

For example, I've had people share with me seeing prolonged silent vigils by crows

举个例子，有人跟我分享说看到 乌鸦长时间对垂死或死去的乌鸦

in response to deceased or dying crows.

沉默守候的情景。

I've even had people tell me of witnessing crows place objects

有人还告诉我，乌鸦会把

like sticks and candy wrappers on or near the bodies of dead crows.

树枝和糖纸放到 死去乌鸦的身上或身旁。

And this mix of observations puts these birds

这些不同的观察让这种鸟

in a really important place in our scheme,

在我们的计划上占有重要地位，

because it suggests on the one hand they might be like the insects,

因为这意味着，一方面， 它们可能跟昆虫一样，

displaying these very predictable behaviors,

表现出非常可预测的行为，

but on the other hand we have this handful of observations

但在另一方面， 我们的有些观察

that are more difficult to explain and feel a bit more like what we see

很难得到合理的解释， 感觉有点像我们看到的

in some of the mammals like primates and elephants.

一些灵长类动物和 大象这类哺乳动物。

And like those animals, crows share an extremely large relative brain size

并且跟这些动物一样， 乌鸦大脑的体积也相对更大，

and the kinds of dynamic social lives that might invite more complexity

并且这种动态的社会生活 可能会让它们

in how they respond to their dead.

对待死者的方式更加复杂。

So I wanted to try to understand what was going on

所以我想搞清楚当乌鸦 遇到死去的同伴时，

when crows encounter a dead crow,

到底会发生什么，

and what this might teach us about the role of death in their world,

以及这能否告诉我们，死亡到底 在它们的世界中扮演着什么角色，

and possibly the worlds of other animals as well,

并且可能事关其他动物，

even those early versions of ourselves.

甚至还有我们的早期版本。

There's a number of different ways that we could explain

有很多理由可以用来解释

why crows might be attracted to their dead.

乌鸦为什么会被死者吸引。

For example, maybe it's a social opportunity,

例如，这也许是个社交契机，

a way for them to explore why that individual died,

一个让它们探讨死者为什么死亡，

who they were

死者是谁，

and what impact this is going to have on the neighborhood moving forward.

这会对社区的发展产生 什么影响的方式。

Maybe it's an expression of grief,

也许这是一种悲伤的表达，

like our own contemporary funerals.

就像我们现在的葬礼一样。

Or maybe it's a way that they learn about danger in their environment.

或者这可能是它们试探 环境是否危险的一种方式。

While all of those explanations are worth pursuing,

所有这些解释都是值得探索的，

and certainly not mutually exclusive,

并且当然不是相互排斥的，

they're not all testable scientific questions.

它们都不是可以 进行测试的科学问题。

But that idea that dead crows might act as cues of danger, that is.

但死去的乌鸦可能意味着危险这一点， 是可以进行测试的。

So as a graduate student, I wanted to explore that question,

作为一名研究生， 我很想探究这个问题，

particularly with respect to two ideas.

尤其是其中两点。

The first was whether they might be able to learn new predators,

第一点是，它们能否 习得谁是新的天敌，

specifically people,

特别是人类，

based on their association with dead crows.

基于他们和死乌鸦的联系。

And the second was if they might learn places

第二点是，它们能否习得

associated with where they find crow bodies.

发现死乌鸦位置的能力。

So to do this, I would go out into some unsuspecting Seattle neighborhood

为了实现这些，我前往了 一些毫无戒备的西雅图社区，

and I would start to feed a breeding pair of crows

开始在三天的时间中

over the course of three days,

投喂一对正在繁殖的乌鸦，

and this provided a baseline

这为乌鸦多快到达

for how quickly the crows would come down to a food pile,

食物堆提供了一个基准，

which, as you'll see in a minute, was really important.

各位马上就会看到，这点非常重要。

Then, on the fourth day,

然后，第四天，

we would have our funeral.

我们会举行葬礼。

This is Linda.

这是琳达。

Linda is one of seven masks whose job was to stand there for 30 minutes

琳达是被放置在实验场地 30 分钟的七个面具人之一，

with her little hors d'oeuvre plate of dead crow

端着一只死乌鸦，

while I documented what happened.

而我则记录了之后发生的事情。

Most importantly, though,

最关键的是，

her job was to come back after a week,

她的工作是一周后再一次出现，

now without the dead crow,

但不再端着死乌鸦，

so that we could see if the birds would treat her just like any old pedestrian,

这样我们就可以观察鸟儿们 是像对待路人那样对待她，

or if, instead, they would exhibit behaviors like alarm calling

还是相反，它们会发出报警呼叫

or dive bombing

或俯冲轰炸等行为，

that would indicate that they perceived her as a predator.

把她视为捕食者。

Now, given that we already knew crows were capable of learning

现在我们已知， 乌鸦有学习能力，

and recognizing human faces,

并可以识别人类面孔，

it may come as no surprise that the majority of crows in our study

那么我们研究的大多数乌鸦

did treat the masks that they saw handling dead crows as threats

在未来的 6 周中 把端着死乌鸦的面孔

when they saw them over the course of the next six weeks.

视为威胁就不让人惊讶了。

Now, if you're sitting there thinking,

如果你们现在正在想，

alright, give me a break,

得了吧，

look at that face, it is terrifying,

看看这个面孔，多可怕呀，

anyone would treat that as a threat

如果人们走在街上看到她，

if they saw it walking down the street,

都会将其视为威胁，

know that you are not alone.

不是只有你会这样看。

As it turns out, a lot of the folks

结果，让我们在他们的家门口

whose houses we did these experiments in front of

进行这个实验的人中，

felt the same way,

很多人都有同样的感觉，

but we'll save that for another time.

但这就是另一个话题了。

So you may be comforted to know that we did control tests

好消息是， 我们做了对照测试，

to make sure that crows don't share our preconceived bias against masks

以确保乌鸦不会像我们一样，对有点像 汉尼拔·莱克特（小说中的食人医师）的

that look a bit like the female version of Hannibal Lecter.

女性版面孔抱有偏见。

Now, in addition to finding that crows were able to make associations with people

那么，除了发现乌鸦可以 对处理死乌鸦的人

based on their handling of dead crows,

产生联系之外，

we also found that in the days following these funeral events,

在这些葬礼事件后仍然 继续喂养它们的日子里，

as we continued to feed them,

我们还发现，

that their willingness to come down to the food pile significantly diminished,

它们飞到食物堆的意愿显著减少，

and we didn't see that same kind of decline in our control groups.

但我们的对照组并没有 同样水平的减少。

So that suggests that, yes, crows can make associations

所以这表明，没错，乌鸦可以

with particular places where they've seen dead crows.

与看到死乌鸦的地方产生联系。

So together, what that tells us is that

那么这一系列结果表明，

while we certainly shouldn't discount those other explanations,

我们显然不该忽视其他解释，

we can feel pretty confident in saying

我们可以充满信心地说，

that for crows, attention to their dead

对乌鸦而言，关注死者

might be a really important way

可能是这些动物试探危险环境的

that these animals learn about danger.

非常重要的方式。

And that's a nice, tidy little narrative

这是一个逻辑严谨的小故事，

on which to hang our hats.

很有说服力。

But in life and death,

但对于生与死，

things are rarely so neat,

事情很少如此简单，

and I really came face to face with that in a follow-up experiment,

在接下来观察 捕食者不在场时

where we were looking at how crows respond to dead crows

乌鸦对死者做何反应的实验中，

in the absence of any kind of predator.

我直击了这个问题。

And suffice it to say, we found that in these cases,

这样说吧，我们发现 在这些案例中，

the wakes can get a little more weird.

乌鸦会变得有些奇怪。

So this is what that experimental setup looks like.

这是实验设置的样子。

You can see our stuffed dead crow alone on the sidewalk,

你可以看到行人道上的乌鸦标本，

and it's been placed on the territory of a pair.

它被放在一对乌鸦的领地上。

(Squawk)

(尖鸣)

That is the alarm call by one of those territorial birds,

这是其中一只领地鸟 发出的警告，

and it's coming into frame.

它开始进入了画面。

Pretty soon, its mate is going to join it.

很快，它的配偶加入进来。

And so far, this is all very usual.

到目前为止，这些行为都很常见。

This is what crows do.

这些是乌鸦的行为。

OK, right now it's getting a little less usual.

好吧，现在有些不太正常了。

Not everyone here might be familiar with what bird sex looks like,

并非每个人都熟悉 乌鸦交配的样子，

so if you are not, this is what it looks like.

如果你不熟悉，大概就是这样子。

You're basically seeing a confluence of three behaviors:

基本上你看到的是 三种行为的混合：

alarm, as indicated by the alarm calling;

警报，类似报警呼叫；

aggression, as indicated by the very forceful pecking

攻击性，体现在交配的鸟儿

by both one of the copulatory birds and one of the excited bystanders;

强有力的啄食行为上， 以及一个兴奋的旁观者；

and sexual arousal.

还有性兴奋。

Clearly, this is startling,

显然，这很让人吃惊，

and interesting to think about and talk about.

很容易引起思考和讨论。

But if our goal is to understand

但我们的目标是理解

the big picture of how animals interact with their dead,

动物如何与它们的死者 互动的整体情况，

then the most important question we should ask is, is this representative?

那我们该问的最重要问题是， 这具有代表性吗？

Is this something that's happening consistently?

这是会持续发生的事情吗？

And that's why being able to do systematic studies with crows

这就是为何对乌鸦 进行系统研究

is so valuable,

是如此有价值，

because after conducting hundreds of these trials,

因为在进行数百次这些实验，

where I was placing these dead crows out on the sidewalks

把死乌鸦放在数百对不同的

on the territories of hundreds of different pairs,

乌鸦领地的路旁后，

what we found was that, no, it's not.

我们发现，不是的， 这些都并非是持续的行为。

Contact of any kind,

任何形式的接触，

whether it was sexual, aggressive

不管是交配、攻击，

or even just exploratory,

甚至只是探究，

only occurred 30 percent of the time.

发生的几率只有 30%。

So given that this wasn't representative,

所以鉴于这些行为 不具有代表性，

this was the minority,

只是少数情况，

we may be tempted to just dismiss it

我们可能会忽略它

as irrelevant, odd, creepy, weird crow behavior.

为不相关的、奇怪的， 令人毛骨悚然的乌鸦行为。

But what may surprise you is that behaviors like aggression

但可能会让你惊讶的是， 攻击性，

or even sexual arousal

甚至性兴奋，

aren't all that rare,

都并不罕见，

and certainly aren't constrained to just crows.

当然也不仅限于乌鸦。

Because while the popular narrative when it comes to animal death behaviors

因为当谈到动物 对待死者的行为时，主流叙事

tends to focus on affiliative behaviors

倾向于关注梳毛或守卫

like grooming or guarding,

这些友好的行为，

that is far from the complete list of what even our closest relatives do

但这些行为与 我们的近亲对待死者的方式

around their dead.

依然相去甚远。

In fact, we've documented behaviors like biting, beating and even sex itself

事实上，我们记录到了 各种各样的动物，

in a wide variety of animals,

包括许多灵长类动物 和海豚在内的

including many primates and dolphins.

诸如咬、打，甚至性本身的行为，

So where does this leave us in our understanding of animals

那么这对我们理解动物 和它们的死亡仪式

and their death rituals?

提供了什么启示呢？

Well, for crows, it suggests that,

对乌鸦来说，这意味着，

like insects, they may have a strong adaptive driver

像昆虫一样，它们对死者的兴趣中

in their interest in their dead.

有强烈的适应性驱动。

In this case, it might be danger learning,

在这个案例中， 它可能是习得危险，

and that might have acted as the inspiration

这可能也是 我们人类仪式的

for our own rituals as well.

灵感来源。

But when we look more closely,

但当我们更仔细地观察，

we see that there's no one simple narrative

就会发现，并不存在 一个简单的叙事，

that can explain the vast array of behaviors

能够解释我们在乌鸦 和很多其他动物上

we see in crows and many other animals.

看到的大量多样化行为。

And that suggests that we are still far from completing that time machine.

这也意味着，我们离 完成时间机器还为时过早。

But it's going to be a really fascinating ride.

但这将会是一段 非常令人着迷的旅程。

Thank you.

谢谢。

(Applause)

(鼓掌)