What crows teach us about death | Kaeli Swift

譯者: Lilian Chiu 審譯者: Helen Chang

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

不論我們想要與否，人類都會花

很多時間在思索死亡。

considering death.

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

且很有可能在現代人 開始在陸上漫遊後沒多久，

first began roaming the landscape.

我們就開始思索死亡了。

After all, the first intentional human burial

畢竟一般認為，最早刻意地埋葬人類

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

大約發生在十萬年前。

What might those early people have been thinking

當時先民的腦袋裡有什麼念頭呢？

當他們慢條斯理地挖洞、

as they took the time to dig into the earth,

deposit the body

放入屍體、小心掩埋的時候， 腦袋裡想著什麼呢？

and carefully cover it up again?

Were they trying to protect it from scavengers

他們是想要保護屍體 不被食腐動物發現？

or stymie the spread of disease?

或者讓疾病難以傳播？

Were they trying to honor the deceased?

他們是在對死者表示敬意嗎？

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

或者他們只是不想要看到死屍？

Without the advent of a time machine,

若沒有時間機器，

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

我們可能永遠不能肯定 早期的人在想什麼，

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

但我們確實知道，

會關注死者的，絕對不只有人類。

in our attention towards the dead.

Like people, some animals,

有些動物和人類一樣，

including the corvids, the family of birds

包括鳥類的親戚，鴉科，

that houses the crows, ravens, magpies and jays,

包括烏鴉、渡鴉、喜鵲、松鴉

also seem to pay special attention to their dead.

都特別關注牠們死去的同伴。

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

事實上，鴉科的儀式可能 是我們人類儀式的靈感來源。

for our own.

After all, it was the raven that God sent down

畢竟上帝派遺渡鴉下凡，

to teach Cain how to bury his slain brother Abel.

教導該隱如何埋葬 被他所殺的兄弟亞伯。

But despite this clear recognition by early people that other animals

但，儘管早期的人很清楚知道

attend to their dead,

其他動物會處理牠們死去的同伴，

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

一直到最近，科學才真正

把注意力轉向這個現象。

towards this phenomenon.

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

事實上，一直到 2016 年，這個領域

wasn't first introduced until 2016.

才有了正式名稱——比較死亡學。

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

在這個成長中的領域裡， 我們才剛開始了解大自然

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

在動物和其死者的互動上 是多麼地多采多姿，

and it's in this growing body of knowledge

在這個持續成長的知識體系中，

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

確實有可能用時間機器 回去看我們的祖先。

So what are we learning in this growing field?

在這個成長中的領域裡， 我們學到了什麼？

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

目前，我們所學到的 可以分成兩大類。

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

第一大類中的動物，會對牠們的死者

展現出刻板、可預測的行為，

towards their dead,

and for whom much of what we understand about them

且我們對這些動物的了解

comes from experimental studies.

多半來自於實驗研究。

This group includes things like the social insects --

屬於這一大類的包括社會性昆蟲——

bees and ants and termites --

蜜蜂、螞蟻、白蟻——

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

對所有這些動物而言， 巢穴的衛生極度重要，

and so as a result these animals display rigorous undertaking behaviors

因此，這些動物對於屍體的反應

就是採取嚴格的下葬行為。

in response to corpses.

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

比如，牠們可能會直接 把屍體搬離群體的屬地，

They may consume them.

可能會吃掉屍體，

They may even construct tombs.

甚至造墓。

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

在一些群居生活的哺乳類動物身上 也會看到出於衛生的反應。

Rats, for example, will reliably bury cage-mates

比如，老鼠會很確實地

將死亡四十八小時的籠中夥伴埋葬。

that have been dead for 48 hours.

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

另一大類的動物則呈現出多變、

perhaps more charismatic behaviors,

可能更有魅力的行為，

and for whom much of what we understand about them

而我們對這些動物的了解

comes from anecdotes

多半來自於科學家 或其他觀察者提出的軼事。

by scientists or other observers.

This is the animals whose death behaviors

我猜想這些動物的死亡行為

I suspect might be more familiar to folks.

可能是人類比較熟悉的。

It includes organisms like elephants,

這些生物包括大象，

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

眾所皆知，大象會照料死亡的同類， 就連在流行文化中也一是。

even in popular culture.

In fact, they're even known to be attracted

事實上，牠們還因會被 死亡大象的骨頭吸引而聞名。

to the bones of their deceased.

It also includes animals like primates,

這一大類也包括靈長類動物，

which display a wide variety of behaviors around their dead,

牠們對於死者的行為就形形色色，

from grooming them

從清洗死者，

to prolonged attention towards them,

到長時間關注死者，

guarding them,

守著死者，

even the transportation of dead infants.

甚至會運送死亡的幼兒。

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

在許多動物身上都會看到這種行為，

like the dolphins for example.

比如海豚。

You may remember the story of Tahlequah,

你可能還記得塔勒夸的故事，

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

普吉特海灣 J 群的虎鯨，

who during the summer of 2018

在 2018 年夏天，

carried her dead calf

牠帶著死亡的幼鯨長達 十七天，前所未見。

for an unprecedented 17 days.

Now, a story like that

像那樣的故事既讓人心碎 又讓人著迷。

is both heartbreaking and fascinating,

but it offers far more questions than it does answers.

但它帶來的疑問比答案還要多很多。

For example, why did Tahlequah carry her calf

比如，為什麼塔勒夸

要帶著牠的幼鯨這麼長的時間？

for such a long period of time?

Was she just that stricken with grief?

牠只是因為太悲傷了嗎？

Was she more confused by her unresponsive infant?

牠的幼鯨沒有反應讓牠感到困惑嗎？

Or is this behavior just less rare in orcas

還是這種行為在虎鯨中

than we currently understand it to be?

沒有我們目前認為的那麼稀有？

But for a variety of reasons,

但，基於許多理由，

it's difficult to do the kinds of experimental studies

很難針對像虎鯨或許多其他

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

大型哺乳類動物進行實驗研究，

that might elucidate those kinds of questions.

因此無法解答這類問題。

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

所以，科學轉向去研究另一種動物，

從西元前我們就已經在思索 這種動物對於死亡的行為了：

we've been thinking about since BCE:

the crows.

烏鴉。

Like insects and primates,

和昆蟲及靈長類一樣，烏鴉似乎 也會特別關照牠們的死者。

crows also seem to pay special attention to their dead.

Typically, this manifests as the discovering bird alarm calling,

通常，具體表現是找到 死者的烏鴉發出警告啼叫，

like you can see in this photo,

如同這張照片，

followed by the recruitment of other birds to the area

接著便是召集其他烏鴉 到死者所在地，

to form what we call a mob.

形成我們所謂的「烏」合之眾。

But it can be a little different than that too.

但也可能有些不同。

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

比如，有人跟我分享說他們看見

烏鴉對於死亡或即將死亡的烏鴉，

in response to deceased or dying crows.

反應是以沉靜的方式做漫長的守夜。

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

甚至有人告訴過我， 他們目擊烏鴉把物體放到

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

烏鴉屍體旁邊，比如枝條和糖果紙。

And this mix of observations puts these birds

將這些觀察混合起來，便讓烏鴉

in a really important place in our scheme,

在我們的體制中佔了很重要的地位，

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

因為，這意味著，一方面， 牠們可能像昆蟲一樣，

displaying these very predictable behaviors,

會做出非常可預測的行為，

but on the other hand we have this handful of observations

但另一方面，我們又觀察到相當多

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

難以解釋的現象，感覺我們所看見的

in some of the mammals like primates and elephants.

更像是靈長類及大象 這些哺乳類動物才會做的事。

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

烏鴉和這些動物一樣， 有非常大的相對腦容量，

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

且牠們活躍的社交生活可能

會讓牠們對死者的反應變得更複雜。

in how they respond to their dead.

So I wanted to try to understand what was going on

所以，我想要了解當烏鴉

遇到死亡的烏鴉時會怎樣，

when crows encounter a dead crow,

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

及這會讓我們對於烏鴉世界中 死亡的角色有怎樣的認識，

and possibly the worlds of other animals as well,

可能還能了解其他動物的世界，

even those early versions of ourselves.

甚至早期的人類。

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

我們可以用好幾種不同的方式解釋

why crows might be attracted to their dead.

為什麼烏鴉會被牠們的死者吸引。

For example, maybe it's a social opportunity,

比如，也許那是個社交機會，

a way for them to explore why that individual died,

讓牠們去探索個體會死亡的原因、

who they were

牠們是誰，

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

以及這對於其群落 向前邁進的影響為何。

Maybe it's an expression of grief,

也許那是悲慟的表現，

like our own contemporary funerals.

就像我們現代的葬禮。

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

或者，也許那是他們學習 環境中有什麼危險的方式。

While all of those explanations are worth pursuing,

雖然所有這些解釋都值得探究，

and certainly not mutually exclusive,

且肯定不互斥，

they're not all testable scientific questions.

但這些問題並非都是 可以檢測的科學問題。

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

但「死亡烏鴉可能是危險的信號」 就是可以檢測的科學問題。

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

所以，我在當研究生時 就想探究這個問題，

particularly with respect to two ideas.

特別是想研究兩個想法。

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

第一，牠們是否能 辨識出新的捕食性動物，

specifically people,

特別是人，

based on their association with dead crows.

根據人和死亡烏鴉 之間的關聯來判斷。

And the second was if they might learn places

第二，牠們是否能了解哪些地點

associated with where they find crow bodies.

和發現死亡烏鴉的地方有關。

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

為此，我得走入一些 毫無戒心的的西雅圖鄰里，

and I would start to feed a breeding pair of crows

並開始餵食一對繁殖的烏鴉，

over the course of three days,

為期三天的時間，

and this provided a baseline

這樣便能得到基線值，

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

了解烏鴉飛下來 到食物堆的速度有多快，

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

各位馬上就會看到這點的重要性。

Then, on the fourth day,

接著，在第四天，

we would have our funeral.

我們會來辦葬禮。

This is Linda.

這是琳達。

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

琳達是七位假人之一， 她的工作是要在那裡站三十分鐘，

with her little hors d'oeuvre plate of dead crow

像端著開胃小菜盤一樣拿著死烏鴉，

while I documented what happened.

我則負責記錄發生的狀況。

Most importantly, though,

不過，最重要的是， 她的工作是要在一週後返回，

her job was to come back after a week,

now without the dead crow,

這次沒有死烏鴉，

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

讓我們觀察這些烏鴉是否 會把她當作一般行人來看待，

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

或者，牠們反而會做出 類似拉警報的行為，

or dive bombing

或俯衝轟炸，

that would indicate that they perceived her as a predator.

那就表示牠們認定她是捕食性動物。

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

我們已經知道烏鴉有學習能力，

and recognizing human faces,

且會辨視人臉，

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

並不意外，在我們的研究中，

大部分的烏鴉的確會把 拿著死烏鴉的假人視為威脅，

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

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

在接下來的六週中 牠們看到假人的反應皆是如此。

Now, if you're sitting there thinking,

如果在座各位正在想，

alright, give me a break,

少來了，拜託，

look at that face, it is terrifying,

看看那張臉，很嚇人哪，

anyone would treat that as a threat

任何人在街上看到這種假人

if they saw it walking down the street,

都會把它視為威脅的，

know that you are not alone.

那你們並不孤單。

As it turns out, a lot of the folks

我們在住戶的房子前做實驗，

whose houses we did these experiments in front of

結果發現許多住戶也有同感，

felt the same way,

but we'll save that for another time.

但那就要下次再談了。

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

我們有做控制檢定， 這點應該會讓各位比較舒服，

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

我們確保烏鴉並不像我們 會對這個有點像女版漢尼拔的面具

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

有先入為主的成見。 （註：《沉黑的羔羊》殺人魔）

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

除了發現烏鴉能夠根據 人拿著死烏鴉的舉動

來建立和這些人的關聯性之外，

based on their handling of dead crows,

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

我們也發現，在這些 葬禮事件之後的日子，

as we continued to feed them,

我們即使持續餵食烏鴉，

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

烏鴉向下飛到食物堆的 意願明顯消失了，

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

在我們的控制組中並沒有 看到這種意願下降的現象。

So that suggests that, yes, crows can make associations

那就意味的，是的， 烏鴉能夠針對牠們

with particular places where they've seen dead crows.

看見死烏鴉的地點來建立關聯性。

So together, what that tells us is that

所以，總的來說，我們得知，

while we certainly shouldn't discount those other explanations,

雖然我們肯定不應該懷疑其他解釋，

we can feel pretty confident in saying

但我們可以很有信心地說，

that for crows, attention to their dead

對烏鴉而言，關注牠們的死者

might be a really important way

可能是牠們學習危險的重要方式。

that these animals learn about danger.

And that's a nice, tidy little narrative

這個很不錯且井然有序的小小說法

on which to hang our hats.

還蠻可信的。

But in life and death,

但，在生死當中，

things are rarely so neat,

凡事很少如此美好，

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

在一項後續實驗中，我真的就 面對面見到了這種狀況，

where we were looking at how crows respond to dead crows

在實驗中，我們要研究在沒有 任何捕食性動物出現的情況中

in the absence of any kind of predator.

烏鴉對死烏鴉的反應。

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

就這樣說吧，在這些情況中，

the wakes can get a little more weird.

我們發現守靈會變得更奇怪些。

So this is what that experimental setup looks like.

這是實驗中我們做的安排。

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

我們把填充死烏鴉 單獨放在人行道上，

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

牠被放置在一對烏鴉的領土上。

(Squawk)

（粗聲叫）

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

這是這塊領土的其中 一隻烏鴉發出的警告，

and it's coming into frame.

牠就要進到畫面中了。

Pretty soon, its mate is going to join it.

沒多久，牠的配偶就會來加入牠。

And so far, this is all very usual.

目前，一切都很正常。 烏鴉都是這樣做的。

This is what crows do.

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

好，現在開始有一點不尋常了。

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

不是每個人都熟悉 鳥類做愛是什麼樣子，

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

如果你不熟悉，它就是這樣子的。

You're basically seeing a confluence of three behaviors:

基本上，你會看到 三種行為加在一起：

alarm, as indicated by the alarm calling;

警告，表現出來就是發出叫聲；

aggression, as indicated by the very forceful pecking

侵略，表現出來就是非常用力去啄，

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

其中一隻在性交的鳥，及興奮的 旁觀者之一都做出這個行為；

and sexual arousal.

還有性興奮。

Clearly, this is startling,

很顯然，這很讓人吃驚，

and interesting to think about and talk about.

說起來和想起來也是挺有趣的。

But if our goal is to understand

但，如果我們的目標是要了解

the big picture of how animals interact with their dead,

動物如何和其死者互動的總體現象，

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

那麼我們應該要問的問題當中， 最重要的應該是：這有代表性嗎？

Is this something that's happening consistently?

這種發生的現象有一致性嗎？

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

那就是為什麼針對烏鴉做系統性研究

is so valuable,

是如此有價值，

because after conducting hundreds of these trials,

因為，在進行了數百次 這樣的試驗之後，

where I was placing these dead crows out on the sidewalks

也就是我將死烏鴉放置在人行道上，

on the territories of hundreds of different pairs,

地點分別隸屬於數百對 不同的烏鴉的領土，

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

我們發現，不，並不一致。

Contact of any kind,

任何形式的接觸，

whether it was sexual, aggressive

不論是性、侵略，

or even just exploratory,

或甚至只是探索，

only occurred 30 percent of the time.

只有 30% 的時候會發生。

So given that this wasn't representative,

所以，既然這並沒有代表性， 只是少數烏鴉的行為，

this was the minority,

we may be tempted to just dismiss it

我們很可能會想要把這種行為 當作是不重要、奇怪、

as irrelevant, odd, creepy, weird crow behavior.

詭異、另類的烏鴉行為，就不管了。

But what may surprise you is that behaviors like aggression

但，可能會讓各位驚訝的是， 像侵略這樣的行為，

or even sexual arousal

或甚至性興奮，

aren't all that rare,

並不那麼稀有，且肯定不限於烏鴉。

and certainly aren't constrained to just crows.

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

因為，就動物對死亡的行為方面，

雖然普遍的說法 傾向聚焦於親和的行為，

tends to focus on affiliative behaviors

like grooming or guarding,

比如照料和守護，

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

但就連我們最相近的動物

對於死者的行為也遠遠不只這些。

around their dead.

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

事實上，我們記錄到的行為包括：

咬、打，甚至性，

in a wide variety of animals,

且多種動物如此，

including many primates and dolphins.

包括許多靈長類和海豚。

So where does this leave us in our understanding of animals

所以，在了解動物 和牠們的死亡儀式方面，

and their death rituals?

我們學到了什麼？

Well, for crows, it suggests that,

嗯，就烏鴉來說，這就表示，

like insects, they may have a strong adaptive driver

牠們和昆蟲一樣， 對於死者的興趣當中

in their interest in their dead.

含有很強的適應動因。

In this case, it might be danger learning,

在這個情況下， 可能是學習什麼是危險，

and that might have acted as the inspiration

我們人類所做儀式也有可能 是從這裡衍生出來的。

for our own rituals as well.

But when we look more closely,

但，當我們更仔細研究，

we see that there's no one simple narrative

會發現沒有單一種說法

that can explain the vast array of behaviors

可以解釋我們在烏鴉 及許多其他動物身上

we see in crows and many other animals.

所看到的各式各樣行為。

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

那就表示，要完成那台時間機器， 我們還有很長的路要走。

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

但，那會是趟非常棒的旅程。

Thank you.

謝謝。

(Applause)

（掌聲）