What crows teach us about death
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0:01 - 0:04Whether we want to or not,
humans spend a great deal of time -
0:04 - 0:06considering death.
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0:06 - 0:10And it's possible we've been doing so
since shortly after homo sapiens -
0:10 - 0:13first began roaming the landscape.
-
0:13 - 0:15After all, the first
intentional human burial -
0:15 - 0:19is thought to have occurred
around 100,000 years ago. -
0:20 - 0:23What might those early people
have been thinking -
0:23 - 0:26as they took the time
to dig into the earth, -
0:26 - 0:27deposit the body
-
0:27 - 0:30and carefully cover it up again?
-
0:30 - 0:33Were they trying
to protect it from scavengers -
0:33 - 0:35or stymie the spread of disease?
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0:36 - 0:38Were they trying to honor the deceased?
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0:38 - 0:42Or did they just not want
to have to look at a dead body? -
0:42 - 0:44Without the advent of a time machine,
-
0:44 - 0:48we may never know for sure
what those early people were thinking, -
0:48 - 0:51but one thing we do know
is that humans are far from alone -
0:51 - 0:54in our attention towards the dead.
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0:54 - 0:56Like people, some animals,
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0:56 - 0:58including the corvids, the family of birds
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0:58 - 1:02that houses the crows,
ravens, magpies and jays, -
1:02 - 1:05also seem to pay
special attention to their dead. -
1:05 - 1:09In fact, the rituals of corvids
may have acted as the inspiration -
1:09 - 1:10for our own.
-
1:10 - 1:13After all, it was the raven
that God sent down -
1:13 - 1:17to teach Cain how to bury
his slain brother Abel. -
1:17 - 1:21But despite this clear recognition
by early people that other animals -
1:21 - 1:22attend to their dead,
-
1:22 - 1:26it's only fairly recently that science
has really turned its attention -
1:26 - 1:28towards this phenomenon.
-
1:28 - 1:32In fact, a formal name for this field --
comparative thanatology -- -
1:32 - 1:34wasn't first introduced until 2016.
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1:35 - 1:39In this growing field, we are beginning
to appreciate what a rich place -
1:39 - 1:44the natural world is with respect to how
other animals interact with their dead, -
1:44 - 1:46and it's in this growing body of knowledge
-
1:46 - 1:50that that time machine
to our early ancestors might be possible. -
1:51 - 1:55So what are we learning
in this growing field? -
1:55 - 1:59Well, right now we can split
our understanding into two main groups. -
1:59 - 2:04In the first, we have animals that display
stereotyped, predictable behaviors -
2:04 - 2:05towards their dead,
-
2:05 - 2:07and for whom much
of what we understand about them -
2:07 - 2:10comes from experimental studies.
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2:10 - 2:13This group includes things
like the social insects -- -
2:13 - 2:15bees and ants and termites --
-
2:15 - 2:19and for all of these animals,
colony hygiene is of critical importance, -
2:19 - 2:23and so as a result these animals
display rigorous undertaking behaviors -
2:23 - 2:25in response to corpses.
-
2:25 - 2:29For example, they may physically
remove carcasses from the colony. -
2:29 - 2:30They may consume them.
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2:30 - 2:33They may even construct tombs.
-
2:33 - 2:37We see similar hygiene-driven responses
in some colony-living mammals. -
2:37 - 2:40Rats, for example,
will reliably bury cage-mates -
2:40 - 2:43that have been dead for 48 hours.
-
2:44 - 2:48In our other group, we have animals
that display more variable, -
2:48 - 2:50perhaps more charismatic behaviors,
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2:50 - 2:53and for whom much
of what we understand about them -
2:53 - 2:54comes from anecdotes
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2:54 - 2:57by scientists or other observers.
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2:58 - 3:00This is the animals whose death behaviors
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3:00 - 3:02I suspect might be more familiar to folks.
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3:02 - 3:05It includes organisms like elephants,
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3:05 - 3:08which are well-known
for their attendance to their dead, -
3:08 - 3:10even in popular culture.
-
3:10 - 3:12In fact, they're even known
to be attracted -
3:12 - 3:14to the bones of their deceased.
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3:14 - 3:16It also includes animals like primates,
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3:16 - 3:19which display a wide variety
of behaviors around their dead, -
3:19 - 3:21from grooming them
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3:21 - 3:25to prolonged attention towards them,
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3:25 - 3:26guarding them,
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3:26 - 3:29even the transportation of dead infants.
-
3:29 - 3:32And that's actually a behavior
we've seen in a number of animals, -
3:32 - 3:35like the dolphins for example.
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3:35 - 3:37You may remember the story of Tahlequah,
-
3:37 - 3:40the orca in the resident J pod
in the Puget Sound, -
3:40 - 3:42who during the summer of 2018
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3:42 - 3:44carried her dead calf
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3:44 - 3:47for an unprecedented 17 days.
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3:48 - 3:49Now, a story like that
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3:49 - 3:52is both heartbreaking and fascinating,
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3:52 - 3:56but it offers far more questions
than it does answers. -
3:56 - 3:59For example, why
did Tahlequah carry her calf -
3:59 - 4:01for such a long period of time?
-
4:01 - 4:04Was she just that stricken with grief?
-
4:04 - 4:08Was she more confused
by her unresponsive infant? -
4:08 - 4:11Or is this behavior
just less rare in orcas -
4:11 - 4:13than we currently understand it to be?
-
4:14 - 4:15But for a variety of reasons,
-
4:15 - 4:19it's difficult to do the kinds
of experimental studies -
4:19 - 4:22in an animal like an orca,
or many of these other large mammals, -
4:22 - 4:25that might elucidate
those kinds of questions. -
4:25 - 4:29So instead, science is turning
to an animal whose behaviors around death -
4:29 - 4:31we've been thinking about since BCE:
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4:32 - 4:34the crows.
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4:34 - 4:35Like insects and primates,
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4:35 - 4:39crows also seem to pay
special attention to their dead. -
4:39 - 4:42Typically, this manifests
as the discovering bird alarm calling, -
4:42 - 4:44like you can see in this photo,
-
4:44 - 4:47followed by the recruitment
of other birds to the area -
4:47 - 4:48to form what we call a mob.
-
4:49 - 4:52But it can be a little
different than that too. -
4:52 - 4:57For example, I've had people share with me
seeing prolonged silent vigils by crows -
4:57 - 4:59in response to deceased or dying crows.
-
5:00 - 5:04I've even had people tell me
of witnessing crows place objects -
5:04 - 5:08like sticks and candy wrappers
on or near the bodies of dead crows. -
5:09 - 5:12And this mix of observations
puts these birds -
5:12 - 5:14in a really important place in our scheme,
-
5:14 - 5:18because it suggests on the one hand
they might be like the insects, -
5:18 - 5:21displaying these
very predictable behaviors, -
5:21 - 5:24but on the other hand
we have this handful of observations -
5:24 - 5:28that are more difficult to explain
and feel a bit more like what we see -
5:28 - 5:31in some of the mammals
like primates and elephants. -
5:31 - 5:36And like those animals, crows share
an extremely large relative brain size -
5:36 - 5:40and the kinds of dynamic social lives
that might invite more complexity -
5:40 - 5:42in how they respond to their dead.
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5:42 - 5:46So I wanted to try to understand
what was going on -
5:46 - 5:49when crows encounter a dead crow,
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5:49 - 5:52and what this might teach us
about the role of death in their world, -
5:52 - 5:55and possibly the worlds
of other animals as well, -
5:55 - 5:57even those early versions of ourselves.
-
5:58 - 6:01There's a number of different ways
that we could explain -
6:01 - 6:04why crows might be
attracted to their dead. -
6:04 - 6:08For example, maybe
it's a social opportunity, -
6:08 - 6:11a way for them to explore
why that individual died, -
6:11 - 6:13who they were
-
6:13 - 6:17and what impact this is going to have
on the neighborhood moving forward. -
6:17 - 6:18Maybe it's an expression of grief,
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6:18 - 6:20like our own contemporary funerals.
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6:21 - 6:25Or maybe it's a way that they learn
about danger in their environment. -
6:26 - 6:29While all of those explanations
are worth pursuing, -
6:29 - 6:31and certainly not mutually exclusive,
-
6:31 - 6:34they're not all testable
scientific questions. -
6:34 - 6:40But that idea that dead crows
might act as cues of danger, that is. -
6:40 - 6:43So as a graduate student,
I wanted to explore that question, -
6:43 - 6:47particularly with respect to two ideas.
-
6:47 - 6:51The first was whether they
might be able to learn new predators, -
6:51 - 6:53specifically people,
-
6:53 - 6:56based on their association
with dead crows. -
6:56 - 6:58And the second was
if they might learn places -
6:58 - 7:03associated with where
they find crow bodies. -
7:03 - 7:07So to do this, I would go out into
some unsuspecting Seattle neighborhood -
7:08 - 7:10and I would start to feed
a breeding pair of crows -
7:10 - 7:12over the course of three days,
-
7:12 - 7:14and this provided a baseline
-
7:14 - 7:17for how quickly the crows
would come down to a food pile, -
7:17 - 7:19which, as you'll see in a minute,
was really important. -
7:20 - 7:21Then, on the fourth day,
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7:21 - 7:22we would have our funeral.
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7:24 - 7:25This is Linda.
-
7:25 - 7:29Linda is one of seven masks whose job
was to stand there for 30 minutes -
7:29 - 7:32with her little hors d'oeuvre
plate of dead crow -
7:32 - 7:35while I documented what happened.
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7:35 - 7:36Most importantly, though,
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7:36 - 7:38her job was to come back after a week,
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7:38 - 7:40now without the dead crow,
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7:40 - 7:44so that we could see if the birds would
treat her just like any old pedestrian, -
7:44 - 7:48or if, instead, they would exhibit
behaviors like alarm calling -
7:48 - 7:50or dive bombing
-
7:50 - 7:53that would indicate
that they perceived her as a predator. -
7:54 - 7:57Now, given that we already knew
crows were capable of learning -
7:57 - 7:59and recognizing human faces,
-
7:59 - 8:03it may come as no surprise
that the majority of crows in our study -
8:03 - 8:07did treat the masks that they saw
handling dead crows as threats -
8:07 - 8:10when they saw them over the course
of the next six weeks. -
8:10 - 8:12Now, if you're sitting there thinking,
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8:12 - 8:14alright, give me a break,
-
8:14 - 8:17look at that face, it is terrifying,
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8:17 - 8:19anyone would treat that as a threat
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8:19 - 8:21if they saw it walking down the street,
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8:21 - 8:23know that you are not alone.
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8:23 - 8:25As it turns out, a lot of the folks
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8:25 - 8:27whose houses we did
these experiments in front of -
8:27 - 8:29felt the same way,
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8:29 - 8:31but we'll save that for another time.
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8:31 - 8:34So you may be comforted to know
that we did control tests -
8:34 - 8:39to make sure that crows don't share
our preconceived bias against masks -
8:39 - 8:42that look a bit like
the female version of Hannibal Lecter. -
8:43 - 8:47Now, in addition to finding that crows
were able to make associations with people -
8:47 - 8:49based on their handling of dead crows,
-
8:50 - 8:53we also found that in the days
following these funeral events, -
8:53 - 8:55as we continued to feed them,
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8:55 - 8:59that their willingness to come down
to the food pile significantly diminished, -
8:59 - 9:03and we didn't see that same kind
of decline in our control groups. -
9:03 - 9:06So that suggests that, yes,
crows can make associations -
9:06 - 9:10with particular places
where they've seen dead crows. -
9:10 - 9:12So together, what that tells us is that
-
9:12 - 9:16while we certainly shouldn't discount
those other explanations, -
9:16 - 9:18we can feel pretty confident in saying
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9:18 - 9:21that for crows, attention to their dead
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9:21 - 9:22might be a really important way
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9:22 - 9:25that these animals learn about danger.
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9:25 - 9:28And that's a nice, tidy little narrative
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9:28 - 9:30on which to hang our hats.
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9:30 - 9:32But in life and death,
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9:32 - 9:34things are rarely so neat,
-
9:34 - 9:38and I really came face to face with that
in a follow-up experiment, -
9:38 - 9:41where we were looking at
how crows respond to dead crows -
9:41 - 9:44in the absence of any kind of predator.
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9:44 - 9:47And suffice it to say,
we found that in these cases, -
9:47 - 9:50the wakes can get a little more weird.
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9:51 - 9:54So this is what that
experimental setup looks like. -
9:54 - 9:56You can see our stuffed dead crow
alone on the sidewalk, -
9:56 - 10:00and it's been placed
on the territory of a pair. -
10:00 - 10:01(Squawk)
-
10:01 - 10:04That is the alarm call
by one of those territorial birds, -
10:04 - 10:05and it's coming into frame.
-
10:06 - 10:09Pretty soon, its mate is going to join it.
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10:12 - 10:15And so far, this is all very usual.
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10:15 - 10:16This is what crows do.
-
10:16 - 10:19OK, right now it's getting
a little less usual. -
10:20 - 10:25Not everyone here might be familiar
with what bird sex looks like, -
10:25 - 10:28so if you are not,
this is what it looks like. -
10:33 - 10:37You're basically seeing
a confluence of three behaviors: -
10:37 - 10:41alarm, as indicated by the alarm calling;
-
10:41 - 10:44aggression, as indicated
by the very forceful pecking -
10:44 - 10:50by both one of the copulatory birds
and one of the excited bystanders; -
10:50 - 10:51and sexual arousal.
-
10:51 - 10:54Clearly, this is startling,
-
10:54 - 10:58and interesting to think about
and talk about. -
10:58 - 11:00But if our goal is to understand
-
11:00 - 11:04the big picture of how animals
interact with their dead, -
11:04 - 11:08then the most important question
we should ask is, is this representative? -
11:08 - 11:11Is this something
that's happening consistently? -
11:11 - 11:14And that's why being able to do
systematic studies with crows -
11:14 - 11:16is so valuable,
-
11:16 - 11:18because after conducting
hundreds of these trials, -
11:18 - 11:21where I was placing these dead crows
out on the sidewalks -
11:21 - 11:24on the territories
of hundreds of different pairs, -
11:24 - 11:27what we found was that, no, it's not.
-
11:27 - 11:28Contact of any kind,
-
11:28 - 11:31whether it was sexual, aggressive
-
11:31 - 11:32or even just exploratory,
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11:32 - 11:35only occurred 30 percent of the time.
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11:35 - 11:39So given that this wasn't representative,
-
11:39 - 11:40this was the minority,
-
11:40 - 11:42we may be tempted to just dismiss it
-
11:42 - 11:46as irrelevant, odd, creepy,
weird crow behavior. -
11:46 - 11:49But what may surprise you
is that behaviors like aggression -
11:50 - 11:52or even sexual arousal
-
11:52 - 11:53aren't all that rare,
-
11:53 - 11:56and certainly aren't
constrained to just crows. -
11:56 - 12:00Because while the popular narrative
when it comes to animal death behaviors -
12:00 - 12:03tends to focus on affiliative behaviors
-
12:03 - 12:05like grooming or guarding,
-
12:05 - 12:10that is far from the complete list
of what even our closest relatives do -
12:10 - 12:12around their dead.
-
12:12 - 12:18In fact, we've documented behaviors
like biting, beating and even sex itself -
12:18 - 12:19in a wide variety of animals,
-
12:19 - 12:22including many primates and dolphins.
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12:24 - 12:27So where does this leave us
in our understanding of animals -
12:27 - 12:28and their death rituals?
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12:29 - 12:32Well, for crows, it suggests that,
-
12:32 - 12:36like insects, they may have
a strong adaptive driver -
12:36 - 12:37in their interest in their dead.
-
12:37 - 12:40In this case, it might be danger learning,
-
12:40 - 12:42and that might have acted
as the inspiration -
12:42 - 12:44for our own rituals as well.
-
12:45 - 12:47But when we look more closely,
-
12:47 - 12:50we see that there's
no one simple narrative -
12:50 - 12:53that can explain
the vast array of behaviors -
12:53 - 12:55we see in crows and many other animals.
-
12:56 - 13:01And that suggests that we are still
far from completing that time machine. -
13:01 - 13:05But it's going to be
a really fascinating ride. -
13:05 - 13:07Thank you.
-
13:07 - 13:10(Applause)
- Title:
- What crows teach us about death
- Speaker:
- Kaeli Swift
- Description:
-
Rituals for the dead span much of the natural world, seen in practices from humans and elephants to bees, dolphins and beyond. With charm and playful insight, animal behaviorist Kaeli Swift delves into the life (and death) habits of crows and shares what their responses could reveal about our own relationship to mortality.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 13:24
Erin Gregory approved English subtitles for What crows teach us about death | ||
Erin Gregory edited English subtitles for What crows teach us about death | ||
Joanna Pietrulewicz accepted English subtitles for What crows teach us about death | ||
Joanna Pietrulewicz edited English subtitles for What crows teach us about death | ||
Joanna Pietrulewicz edited English subtitles for What crows teach us about death | ||
Joseph Geni edited English subtitles for What crows teach us about death | ||
Joseph Geni edited English subtitles for What crows teach us about death |