Book Sheds New Light on Baboon Social Scene
Primatologist duo Dorothy Cheney and Robert Seyfarth discuss their new book, Baboon Metaphysics: The Evolution of a Social Mind. The husband-and-wife team spent years studying a group of baboons in Botswana, observing their behavior, vocalizations — and even their feces — to better understand the primates' complex social structure.
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DATE December 5, 2007 ACCOUNT NUMBER N/A
TIME 12:00 Noon-1:00 PM AUDIENCE N/A
NETWORK NPR
PROGRAM Fresh Air
Interview: Davied Wilcove of Princeton University on the decline
of animal migration worldwide
TERRY GROSS, host:
This is FRESH AIR. I'm Terry Gross.
You might not be aware of this--I know I wasn't--but the phenomenon of animal
migration is disappearing around the world. The migrations of birds,
butterflies, fish, whales and large mammals are threatened by factors ranging
from cell phone towers to climate change. My guest, David Wilcove, is the
author of the new book "No Way Home: The Decline of the World's Great Animal
Migrations." The book is not only about why migrating animals are threatened,
it's about why these animals travel and how they know when and where to go.
Wilcove is a professor of ecology and evolutionary biology at Princeton
University. I asked him why threats to animal migration matter to a human.
Mr. DAVID WILCOVE: Animal migration in general is a really important
phenomenon. It's, I think, just about the most spectacular thing in wildlife
to see great herds of mammals in Africa or flocks of birds here, but it's also
important ecologically, so in the case of the birds, for example, as these
billions of migratory birds move back and forth every year, they're consuming
vast numbers of insects and they're helping to preserve the health of forests.
GROSS: What else? What are the other ways that migratory animals keep things
in balance and affect the lives of humans?
Mr. WILCOVE: Let's take a look at something like salmon. So salmon are born
in streams, rivers. They migrate out to the ocean. They grow really big, and
then they come back upstream, they spawn and they die. From an ecological
perspective, what they're really doing is gathering nutrients up in the ocean,
coming back up the rivers, spawning, dying, decaying, and releasing those
nutrients into the rivers and streams, and from there it gets onto the land,
and it can be very important of maintaining the health of not just the rivers
but also the adjacent land.
So, for example, studies have shown that a significant fraction of the
nitrogen growing in grapes in California, in the wine country, is actually
nitrogen that was brought there by salmon. In essence, they're transporting
nutrients and helping maintain the productivity of the rivers and the adjacent
land.
GROSS: Now, you write in your book that the closest you can get to actually
flying with the migrating songbirds is to travel with Martin Wikelski, who's a
professor of ecology at Princeton, where you're also a professor of ecology,
and you've accompanied him on at least one of these missions, studying the
migrating birds. How does he actually track birds?
Mr. WILCOVE: Martin is an absolute genius at finding ways to study migratory
birds, and he and his colleagues have developed very small transmitters that
can attach to a thrush. They capture the thrush, attach the transmitter,
release the thrush, and then as the bird migrates in the evening, they pile
into a car or into an airplane and they chase after it. Usually they're in a
car and they're careening through the Midwest late at night, trying to keep up
with this bird that's 1,000 feet above them, heading north in springtime. And
they then try to recapture the bird so they can obtain some key data relating
to its physiology, and in that way determine what the costs of migration are.
But he's done some amazing studies, not only with birds but also with
dragonflies to understand how individual animals migrate and what it means to
them.
GROSS: That's really amazing, you know, that he can attach a little
transmitter to a small and fragile dragonfly. And for anyone who's confused
about which insect the dragonfly is, do you want to describe the dragonfly?
Mr. WILCOVE: Sure. The dragonfly to me look like little fixed-wing
airplanes. They've got a long slender body and two sets of wings that are
held out, and they weigh about--the species that Martin's working on weighs
about 1/30th of an ounce, and he was able to develop a transmitter that weighs
1/100th of an ounce.
GROSS: Wow. That's amazing.
Mr. WILCOVE: That's right. And he attached it to the belly of dragonflies
using some superglue and eyelash adhesive--I'm not sure how he figured out to
use eyelash adhesive--and I was with him for much of this work. You release
the dragonfly, and then he tracked them while they migrated in a small
airplane and...
GROSS: Wait, wait. He was in a small airplane while they migrated?
Mr. WILCOVE: That's right, And we discovered that dragonflies migrate much
the same way birds do. They have their migration days and their rest days,
and when they migrate, they can go considerable distances. One of the
dragonflies that we tracked moved over 80 miles in a single day.
GROSS: So what are some of the more interesting things you've learned about
migrations through studying these dragonflies?
Mr. WILCOVE: We were quite surprised to learn how closely they followed the
behavior of migratory birds, not only in terms of having the travel days and
the rest days, but also they put on fat prior to their migration the way a
bird does, kind of stocking up. And then dragonflies...
GROSS: It doesn't show.
Mr. WILCOVE: No, they carry it well, but they definitely need that extra
energy for these long trips. One of the neat things about dragonflies is they
weigh so little--a hundredth of an ounce--that they really can't afford to fly
against the wind, and most of the time we found that they were migrating in
the direction of the wind. Well, you would think to yourself, that's not a
very sensible approach. How's he going to get you where you want to go? But
in fact they have a very simple rule that they seem to follow; it must be an
ingrained rule, and that is they wait until they have two nights of
successively colder temperatures. So if Monday night is 50 degrees and
Tuesday night is 40 degrees, they will fly on Wednesday morning, and the
reason this seems to work is, in the autumn falling nighttime temperatures
usually mean a cold front is coming through, and that means northwest winds,
which gives them a tailwind in exactly the direction they want to go. So it's
a very simple rule that evolution has developed that helps them with their
migration.
GROSS: Now, doesn't this lead us directly into the problems of climate
change, that migratory animals will be getting the wrong cues at the wrong
time?
Mr. WILCOVE: That's right. They may operate under different sets of cues.
So, for example, a migratory bird in the tropics may use the change in
daylight--which can be just very subtle, just a few minutes a day, but it can
pick that up--and it may use that as the cue that it's time to come back
north. On the other hand, the insects that it depends on for its food, they
depend on temperature, so as the earth gets warmer, it's possible that the
insects will appear earlier but the bird in its wintering grounds either in
Africa or Central America, won't know that, and so it arrives when it has
always headed north only to find that its food is much less abundant because
the insects have already come out and disappeared.
GROSS: You know, in terms of migration, you say climate change is the joker
in the deck, the ultimate effect on migration is as yet undetermined. What do
we know so far about how climate change is affecting migration patterns?
Mr. WILCOVE: The problem with climate change is it can disrupt some of the
very carefully honed relationships between birds and their prey, for example.
In Europe, the pied flycatcher, a small songbird, has been declining because
it times its arrival on its breeding grounds to the growth of the caterpillar
population, and it tanks up on those caterpillars and feeds them to its young.
But with global warming, the caterpillars have been coming out earlier and
earlier. The flycatchers on their wintering grounds in Africa don't know
that, and so they've been arriving at the usual times on their breeding
grounds only to find that there aren't enough caterpillars to raise their
offspring. And these sorts of problems are likely to occur in many other
parts of the world, including the United States.
In other cases, climate change could simply erase important habitats for
migratory species. Sea turtles, for example, have very specific nesting
beaches where they come ashore, lay their eggs; and these nesting beaches can
be used for decades, or even longer. Climate change could easily result in a
rise in sea level and the complete disappearance of these vital nesting
beaches.
GROSS: Now, one animal you write about that was in decline and has made a
comeback is the gray whale. What turned things around for the gray whale?
Mr. WILCOVE: The gray whales represent one of the few real success stories
in saving a rare migratory animal. And they undertake an amazingly long
migration from the Behring Sea down to Baja, California, where they pile into
a few lagoons in Baja, which function as sort of a nursery where the females
give birth to the calves and a singles bar where the unmated male whales pair
up. And when the whalers in the 1800s discovered these lagoons, they quickly
decimated the gray whale population, and so by the beginning of the 20th
century, the gray whale was down to a handful of individuals and it seemed as
though it was destined for extinction.
But they were protected, and then later on an international treaty was
developed to protect the great whales. Meanwhile, the Mexican government took
steps to protect these lagoons, and the gray whale staged an amazing comeback
from probably less than 100 individuals to well over 20,000 today. In fact,
gray whales today are probably as common as they have ever been, and it's been
a great boon for ecotourism because there are lots and lots of companies and
individuals that take tourists out to see the whales, either along the West
Coast of the United States, where they migrate, or down to those lagoons in
Mexico where they calve and where they hang out.
GROSS: Now, you write, "As the gray whales became more valuable alive than
dead, something remarkable happened to the whales themselves: They stopped
fearing people." Would you elaborate on this a little bit? First of all, what
you mean by the gray whales becoming more valuable alive than dead, and how
did they stop fearing people? And were they attacking people before?
Mr. WILCOVE: Sure. The tourism industry that had sprung up around gray
whales, both in the United States and in Mexico, generates far more income
than the dead whales could have via whaling. Now, back in the 1800s, the gray
whale was called the devil fish, and the reason was it had the reputation of
attacking the whaling boats. That's a little unfair to the whales because the
attacks were primarily female whales who were attacking the boats to protect
their calves because the whalers used to harpoon the calf first, knowing that
its mother would not abandon it, and that meant they could kill the calf and
then kill the mother. So the whalers viewed the gray whale as a very
dangerous animal. The gray whale viewed humans as a very dangerous predator,
and there was this antagonistic relationship.
After several decades of protection, where the whales were no longer being
harvested, something very strange happened. Mexican fisherman reported that
when they were around the lagoons where the gray whales spent the winter, some
of the whales were actually coming up to the boats and even allowing
themselves to be scratched on the head and they seemed to like it. And they
would bring their young up to the boat to meet the people, and this has
continued to the present day as more and more whales seem to seek out this
sort of contact with people. And no one is certain what's going on, but my
hunch is the whales recognize the humans are no longer a threat to them and
they are genuinely curious about people and boats. And I also think they like
to get their heads patted.
GROSS: Let's get really small again. In talking about the obstacles to
migration, you say even a new road can wipe out, say, a specie of salamander
who has to get from, you know, one area to another, and you say that you even
spent a day at Stanford trying to help salamanders--like, endangered
salamanders--across a road. Talk about these salamanders a little bit and
what you did to try to help them and why you did it.
Mr. WILCOVE: Sure. In California, in Stanford, there's an endangered
salamander, the California tiger salamander, and they breed in a little pond
and then they move upland into the wooded and shrubby areas for much of the
year, and separating the upland areas from the breeding pond is a road, and
it's a pretty well traveled road in terms of cars. And so when the rains
occur and the salamanders are moving between the breeding pond and the upland
area, concerned citizens organized brigades of students and people to walk
along the road at night with flashlights, find the salamanders and help them
across the road before they get squished by cars. Because, in fact, lots and
lots of them are killed every year by the cars, and since it's an endangered
species, the loss could significantly harm that population. So it was one of
the stranger evenings I spent, but probably one of the more productive ones.
It was a rainy night, the cars are zooming by and I'm walking along the road
with a flashlight and a fluorescent vest and looking for salamanders and, when
I see them, catching them, taking them across the road and releasing them.
GROSS: Now, this is exactly the kind of scenario that a lot of people who
think environmentalists are kind of like silly liberals who don't have their
priorities straight would mock. So tell me why it was important to you to
observe this and participate in the salvation of these endangered salamanders.
Mr. WILCOVE: For a couple of reasons. First, if you haven't seen a
California tiger salamander, it's really a very beautiful animal. It's black
with yellow spots, and I think it's quite an impressive little animal.
Second, because it's an endangered species, we do have to worry about the loss
of the individuals in this population. I frankly wouldn't spend all of my
time helping every salamander try to cross a road, but I think in the case of
an endangered species, it's well worth a small investment of time to prevent
it from becoming extinct.
As far as its ecological role, I'm not going to claim that the loss of the
California tiger salamander would cause some great environmental disaster, but
I do think they're a nice part of the environment and a reminder that, in
California, long before there were cars and people, there were also a lot of
interesting wildlife.
GROSS: You know, you end your book by saying migration is an act of faith.
What do you mean by that?
Mr. WILCOVE: We can look at a migratory bird, a thrush that's going to
undertake a perilous journey from its breeding grounds in Canada to its
wintering grounds in Brazil, and think, `what a brave animal.' But birds
really don't have attributes like bravery or faith or anything like that.
What they do have is an instinct that tells them it's time to migrate, that
tells them where to go and how to get there.
But it occurred to me that that instinct is the result of evolution, thousands
upon thousands of years of natural selection that crafted an animal that could
do all of these things, and, in essence, that genetic programming, that set of
instincts really amounts to faith. Because the animal, while it's migrating,
doesn't know what has happened to its winter home since the last time it was
there, it doesn't know what happened to all of the important stopover places
in between. It just feels a compulsion to go, and it seemed to me that, in a
way, that's a hard-wired faith. And that, of course, shows both the marvel of
migration and the vulnerability of the animals that do migrate.
GROSS: Well, David Wilcove, I want to thank you a lot for talking with us.
Mr. WILCOVE: It's been a pleasure.
GROSS: David Wilcove is the author of the new book "No Way Home: The Decline
of the World's Great Animal Migrations." He's a professor of ecology and
evolutionary biology at Princeton University. I'm Terry Gross, and this is
FRESH AIR.
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Interview: Robert Seyfarth and Dorothy Cheney, husband and wife
team and authors of "Baboon Metaphysics," on observing groups of
baboons in Botswana
TERRY GROSS, host:
This is FRESH AIR. I'm Terry Gross.
You can tell by the title of the book "Baboon Metaphysics" that the authors
want to know what's going on in the minds of baboons. The authors also want
to know what baboons have to say to each other. They've recorded
vocalizations of wild baboons and analyzed what they communicate. We're about
to listen to some of those recordings with the authors of "Baboon
Metaphysics," Dorothy Cheney and Robert Seyfarth. This husband and wife team
has studied baboons in Botswana since 1992. They both teach at the University
of Pennsylvania, where Cheney is a professor of biology and Seyfarth a
professor of psychology.
Dorothy Cheney, Robert Seyfarth, welcome to FRESH AIR. Your new book starts
with a quote from Darwin, and the quote is, "He who understands baboon would
do more towards metaphysics than Locke." What is Darwin talking about?
Mr. ROBERT SEYFARTH: Well, Darwin wrote that in 1838, quite awhile before he
published "The Origin of Species." And he wrote it in one of his notebooks--he
kept voluminous notebooks--and his idea was: People were very interested at
the time in where thinking comes from, why humans think the way they do, why
they perceive and organize the world the way they do, and he began to realize
that he could take his theory of evolution by natural selection and apply it
to the brain, and in so doing apply it to the way people think. And he
suddenly realized that if humans are closely related to nonhuman primates,
like the baboon, that by doing a comparative study of the way nonhuman
primates think and the way humans think, you could begin to understand how
thinking evolved.
GROSS: Do you feel that through your research you're learning about the human
brain and thinking and how it evolved?
Ms. DOROTHY CHENEY: To some degree. Of course, baboons aren't humans and
they lack language and a lot of the sort of mental capacities that human have,
but one of the things that's been intriguing to us about baboons is they live
in these very complex societies that are composed of multiple family lines,
individuals of varying degrees of competitive ability and dominance ranks and
so on. They seem to know a huge amount about each other's social
relationships and each other's dominance ranks, so the social complexity, on
the surface anyway, appears to be very similar to that of a very complex human
society, and yet they're not humans. So the question is, what differentiates
us from them and what sort of selective pressures might have gotten us from an
organism that looks like a baboon to an organism that looks like us.
GROSS: Well, let's listen to some of the vocalizations that you've recorded
of baboons.
Ms. CHENEY: Mm-hmm.
GROSS: Because these are just amazing to listen to. And we're going to start
with grunts. We're going to hear six different baboons, back to back, with
the basic grunt sound. So what should we be listening for?
Mr. SEYFARTH: Well, as you go through this tape you're going to hear the
calls of six females. Each one of them gives two grunts, and you'll notice
that the grunts of any one female, the two that she gives, sound alike, but
they sound very different from the next animal, who's different from the next
animal and so on, so that you can easily imagine that if you were a baboon
living all your life with these different individuals, you very quickly learn
to recognize, `Oh, that's Helen, mm, that's Sylvia' and so on.
GROSS: OK. So here it is, six female baboons, back to back, grunting.
(Soundbite of six baboons grunting)
GROSS: OK, so does each baboon have their own note, basically?
Mr. SEYFARTH: Yeah, you can think of it that way, although it's a little bit
more complicated because it's like six different people saying the same word,
but each individual is a little bit idiosyncratically different.
GROSS: Now, were they all recorded together at the same time? Is that a
conversation we heard?
Ms. CHENEY: No, not in this particular case, but you could easily have a
conversation like that because a typical social interaction might involve a
female walking up to another who has an infant, grunting, and that female with
an infant grunting back. So you do get these kinds of vocal exchanges. And
the vocal exchanges are actually most common when animals are embarking on a
potentially dangerous move--through deep water, for example--and they're given
almost as a sort of exchange to kind of negotiate, `Are we really going here
or not? Are you keeping an eye on me or not?' I mean, that's an
anthropomorphism, but the sort of looks exchanged between animals as they give
these grunts, it's as if they're checking to see what each other's intentions
and motivations are.
GROSS: We have a scream we're going to hear, a baboon scream. When do
baboons scream?
Ms. CHENEY: Well, they scream when they're involved in a fight. And
typically, the screams are given by a lower-ranking animal to a higher-ranking
animal. I should have added earlier that when we're talking about rank in
adult females, rank is not determined by size or age. It's determined
entirely by who your mother is, and so when you're looking at a dominance
hierarchy of females, there could be 26 females ranked in a hierarchy where
female one can supplant or cause to move away female two, and female two can
cause three to move away and so on down the line. What you're really looking
at is groups and clusters of families where females one through four could be
mother, daughter and sister, and then female five belongs to an entirely
different family. So that a lot of these fights and altercations and kind of
negotiations that I was talking about involve not just individuals but entire
families.
GROSS: Well, let's hear a baboon scream.
(Soundbite of baboon scream)
GROSS: Now, that really sounded like a bird to me. You know? Do you hear
that a lot when you're out in the wild with the baboons?
Mr. SEYFARTH: You do.
GROSS: Mm-hmm.
Mr. SEYFARTH: And what you often hear is you hear a sequence of calls, say,
from over somewhere behind a bush, you hear one animal giving a threat grunt
to another animal and the other animal screaming, and this is what baboons
hear all the time, and this is what we wonder, what do they know? What sort
of information do they get when they hear these calls? And the interesting
thing is that you can use these sequences to show that the baboons know
something about each other's ranks. So if we take from our library of calls
the threat grunt of a high-ranking female and play it, followed by the scream
of a low-ranking female, so let's say Sylvia is a high-ranking female and
Hannah is a middle-ranking female, if we play Sylvia's threat grunt and
Hannah's scream, then that's a sort of thing that happens all the time. And
animals don't usually respond.
But if we dig into our library and get too different calls, Hannah's threat
grunt and Sylvia's scream and we put them together in a sequence and we play
that, the animals will look toward the speaker and try and figure out what is
going on. They have a very strong response because that sequence suggests
that Hannah is threatening Sylvia, who we all know to be higher-ranking, and
this violates their existing knowledge. Baboons respond with surprise to
anything that signals that the dominance order isn't exactly what we know it
to be, which suggests that they really understand the rank relations that
exist among others.
GROSS: So you have these hidden speakers in the wild and you play back baboon
sounds for the baboons and see how they respond?
Ms. CHENEY: Exactly.
GROSS: Pretty interesting. OK. Next we're going to hear a female baboon
alarm bark. What is this?
Mr. SEYFARTH: Well, baboons in the area where we study, they are preyed upon
by lions and leopards and also crocodiles, and when they see any one of these
predators, they give a very sharp bark, the females do, and other animals
immediately become very vigilant and may run up into a tree.
GROSS: Let's hear it.
(Soundbite of baboons barking)
Mr. SEYFARTH: And that's a chorus of females giving barks to what was a lion
on that occasion.
GROSS: So hearing all of these different sounds it sounds like baboons have a
fairly wide range of things that they can communicate, different sounds, it's
not just a trademark kind of ...
Mr. SEYFARTH: Yeah, it's...
GROSS: ...singular sound.
Mr. SEYFARTH: They've got a repertoire of calls.
GROSS: Mm-hmm.
Mr. SEYFARTH: And if you think about comparison with humans, what is
striking is that the repertoire of calls, though it's certainly there and a
lot of them express subtle nuances...
GROSS: Mm-hmm.
Mr. SEYFARTH: ...of aggression or subordination, it's really only about 10,
15, maybe 20 different vocalizations...
GROSS: Mm-hmm.
Mr. SEYFARTH: ...so that it's a relatively small repertoire...
Ms. CHENEY: And what separates these calls from human language is they
appear not to be learned. So that if you go to East Africa and you hear a
baboon threatening another, you'll hear a threat grunt. If a Kenyan baboon is
giving an alarm call to a lion, it will sound very much like the same sort of
call that a Botswana baboon gives to a lion. So you don't have any real
dialects as you do in language or as you do, indeed, in birds. So in that
sense their vocalizations are very, very different from human language.
GROSS: Though some people say we're born with--that we're hardwired for
language even though we're not born knowing the words.
Ms. CHENEY: Well, that's certainly true.
GROSS: Yeah.
Ms. CHENEY: But there's still more flexibility in the sense that, you know,
you can teach an individual any language in the world.
GROSS: Right. And baboons just speak baboon.
Ms. CHENEY: They just speak baboon.
GROSS: Right. Well, let's get to another baboon sound, and this is what you
describe as "wahoo"s. Do you want to describe what wahoos are?
Mr. SEYFARTH: Well, in baboon society, as Dorothy said, the females are born
and they live in the same group throughout their lives, and they live in this
hierarchy of matrilineal families, where the mothers and their sisters and
daughters all retain really tight relationships with each other--lots of
grooming, support alliance, and so on. When males get to be fully adult size,
sometime around seven or eight years old, they leave the group where they were
born and they go, often miles away, and join another group where they have to
fight their way to the top of the male dominance hierarchy.
But, as in so many animals, there's a lot more displaying and posturing than
there is actual fighting, and one of the real clear-cut and obvious displays
that male baboons give to each other is this wahoo call. It's one of the
loudest calls than any terrestrial animal makes, and males make it in sort of
contests where one male will start wahooing and the other will respond, and
then the males will run up into trees and leap from branch to branch while
giving these wahoos.
GROSS: And they're just kind of showing off...
Ms. CHENEY: Well...
Mr. SEYFARTH: They're showing off, and...
GROSS: ...for each other.
Ms. CHENEY: They're showing off, but also these are not just displays of
complete bravado, because in order to sustain this very loud, rapid calling
rate as you're racing through the trees, you have to have pretty good stamina,
and so males seem to use these sorts of displays to display and also to assess
each other's stamina and competitive ability so that they actually serve a
function that allow males to assess whether or not they want to escalate the
display into a real physical fight.
GROSS: OK. Well, let's hear a sequence of three different baboons doing
wahoos.
(Soundbite of the baboon wahoo calls)
GROSS: So, these are very loud when you're...
Mr. SEYFARTH: Yeah.
GROSS: ...actually in the wild with them.
Mr. SEYFARTH: Yeah, they're really loud, and you notice that there's the
sort of "wa-hoo," and it's a sort of two-part call. And if, as Dorothy says,
the calls are kind of a contest to see who's the most powerful, who can wahoo
the loudest, the longest, the fastest and still not be out of breath, and as
the males go through these wahoo contests, the hoo begins to drop out and
other sort of aspects of the call make it sound a lot less impressive.
GROSS: Now, you refer to the importance of rank in baboon society, and
there's also calls for low and high-ranking males that you've recorded. Would
you explain what we're about to hear with these calls?
Mr. SEYFARTH: Well, what you're going to hear is a wahoo from a high-ranking
male, and he's high-ranking so right now he's at the top of the hierarchy and
he's in great physical shape and everyone is deferring to him; and contrast
that with the wahoo of a low-ranking male who's at the bottom of the
hierarchy--he may be very old, he may be wounded, he's in not so good
shape--and listen to the different wahoos and you can really hear the
difference between one, the high-ranking male, that really is powerful and has
a long hoo and the other one that's pretty pathetic, really.
GROSS: Here we go.
(Soundbite of male baboons wahoo calls)
Mr. SEYFARTH: So when you hear the first one, wahoo, and then the second
one, the hoo is completely gone. Wa. And that's the best that that
low-ranking male can do. And it sounds much less impressive than the
high-ranking male's.
GROSS: My guests are Robert Seyfarth and Dorothy Cheney, authors of the book
"Baboon Metaphysics." More after a break. This is FRESH AIR.
(Announcements)
GROSS: If you're just joining us, my guests are Dorothy Cheney and Robert
Seyfarth, and they're the authors of the book "Baboon Metaphysics: The
Evolution of a Social Mind." They've been studying baboons for years in
Botswana. They're also both professors at the University of Pennsylvania.
They've been married for about 30 years.
In addition to studying baboon vocalization, baboon language, one of the
things you've been doing in the wild is collecting baboon feces. Now, what
can you learn by analyzing their feces?
Ms. CHENEY: One of the things that's been really interesting about the
development in poop, I guess you'd call it, is that it's now possible to
extract hormones from fecal samples, and as a result you can, in our
particular case what we're looking at stress hormones, glucocorticoid. And
one of the beauties of a poop sample is, of course, you can gather a fecal
sample without actually stressing the animal by capturing it or having to draw
its blood. And so one of the things these fecal samples do is they allow us
to measure stress, and in a sense we can interview the animal almost by asking
her `What's causing you stress? How do you alleviate stress?' And so it's a
wonderful tool that allows us to actually delve more deeply into the baboon's
social structure and look at how animals deal with the many challenges that
they face in their environment, including predation, infanticide, rank
upheavals and so on.
GROSS: And so what does stress out baboons?
Mr. SEYFARTH: Well, there are three things that are really important for
both females and males, and the first is predation. There are months in which
lions attack baboons...
Ms. CHENEY: Lions? Or leopards?
Mr. SEYFARTH: Or leopards attack and the collection of these thousands of
poop samples from 22 females over several years has shown us that in months
when there are predator attacks, everyone's glucocorticoid levels are higher,
so they're under a little bit more stress, it would appear. If a female is
taken by a predator, of course everyone's glucocorticoid levels go up, but the
individuals whose glucocorticoid levels go up the greatest are the victim's
relatives, the members of her matrilineal family or her closest grooming
partners.
GROSS: Well, that's interesting because it shows that family matters, that
there's a special connection between family members in the baboon world.
Mr. SEYFARTH: It is, and collecting these fecal samples tells us something
that we wouldn't otherwise know. I mean, everybody looks like they're under
stress after a lion attack, but the fecal samples, the glucocorticoids, tell
us that really under stress are the relatives of the victim.
But then, of course, in the next few weeks and months, animals' glucocorticoid
levels go back to base line, and we were interested to see how this is a
achieved. And the females who lose a close relative or a close grooming
partner, who have their sort of network of friendships disrupted, they show an
interesting pattern. They increase the number of other females that they
groom with, as if they're seeking out new friends to re-establish a nice,
tight grooming network, and that's interesting because the same sort of thing
happens when the females are faced with the potential of infanticide. When a
new male comes in, he often tries to kill the small infants of females in the
group at the time, and the females respond by forming a tight bond with
another one of the males in the group, kind of friendship, and the females who
are able to do that, their glucocorticoid levels don't go up as much everyone
else does who doesn't form a friendship.
GROSS: You use the word infanticide. Why do new males in a group try to kill
the infants?
Ms. CHENEY: Well, from a male's perspective--an immigrant male's
perspective, it makes a lot of sense. In baboon society, all females breed,
regardless of their relative ranks. But that's not true of males. The males
who achieve the most matings is the dominant male, the alpha male, and the
other males really don't do so well. The problem is there's such high
turnover in the alpha male position that a male can only expect to be alpha
male for about six or seven months, maybe up to a year at most.
So a male coming into a group faces a dilemma. There are all these infants in
the group. Mothers are not going to start cycling again or become sexually
receptive until those infants are weaned. Typically an infant is nursing for
over a year, and pregnancy lasts for six months, so the chances that a male
will be able to retain his alpha position for long enough before these females
become sexually receptive again is very small. So from a male's perspective,
coming in and trying to kill the infants of lactating females makes sense.
After all, these are not his infants, and if these infants are killed, then
the female begins sexual cycling soon.
From the female's perspective, this represents a significant loss in her
reproductive success, so of course they resist it.
GROSS: So does the new alpha baboon want access to, like, every female
baboon? I mean, it's not enough that some of them are already accessible, he
has to kill the babies of the mothers who are lactating?
Ms. CHENEY: In a sense, yes. If a male comes into a group, there may not be
that many cycling females present in the group.
GROSS: Mm-hmm.
Ms. CHENEY: The odd thing when you look at a group of baboons like this is
you can see this new male come in and he's infanticidal, you know, you can't
help but as an observer respond negatively to this because a horrible thing to
observe. For a while you go through this period where you absolutely hate the
male, even though you're supposed to remain objective. But what's interesting
is that once the females he's mated with become pregnant and they produce
offspring of their own, he becomes a doting dad. He protects these infants,
he carries them, he lets them jump on his head and so on. So in some cases
these males who are alpha almost cede their position after they've produced
some offspring of their own. They don't necessarily willingly give up the
alpha position, but they're now--their efforts are devoted more to protecting
their current infants than to fathering additional ones.
GROSS: The baboons can climb up into trees and take shelter there. Have
there been situations in which you've had to hide from lions or tigers or any
other animals of prey?
Mr. SEYFARTH: Everyone has at least one close-call story, and my close-call
story was not watching the baboons, but when I was driving through the
national park to the nearest town for supplies and I got stuck in an
enormously deep rut that I couldn't jack my car out of. So I had to walk back
to the nearest ranger post and I walked into a group of seven lions. And
you're always told, `Do not run.' If you run, a lion is like a sort of cat
with a ball of yarn. It'll go for you and you won't win.
And so I moved as quickly at a walk as I could about 15 meters to the nearest
tree, and I climbed up the tree, and I was very glad that the tree, at the
time, had knobs and little, you know, things that supported my feet and I
thought, as I was going up and I had these lions growling behind me, gee, this
is just like climbing a ladder. It's great. And I made it up to the first
branch, which was about 11 feet off the ground and then I knew I was OK. And
hours later the lions finally went away and I got help.
And about a week later we all went out and decided we would visit this tree
and take some photographs and have a picnic, and it turns out that these
little knobs and branches that provided me with footholds were only about a
32nd of an inch above the surface. They provided no support whatsoever. No
one could climb the tree. Everyone all fell down. So I guess that's the
beauty of adrenaline.
GROSS: I know you've tried to keep like emotional distance from the baboons
and not influence their behavior or become too emotionally attached to them.
Nevertheless, have you become very emotionally attached to them and do you see
them as beautiful animals?
Mr. SEYFARTH: Yes. And as animals with--each one of them with a unique
personality.
Ms. CHENEY: Recently the oldest female in the group, Sylvia, died, and she
was over 25 years old. And she was a real curmudgeon, and when we used to do
these experiments that we do on looking at reconciliation, Sylvia never
reconciled. She was the second-ranking animal in the group, and her attitude
seemed to be, you know, `I should be first-ranking and I'm just not happy
about my life in general. Neither will you be as long as I'm around.' And so
she would cut this swath through the group and sort of beat up animals and so
on.
As she aged, she became a little bit more mellow, and she had a very close
relationship with her only surviving daughter, and in a sense that was the
animal that she groomed with the most, and most the other animals in the
group--anthropomorphizing for a moment--really didn't want to be near Sylvia
because she was such a nasty individual. And then this daughter was killed by
a lion, and Sylvia's stress levels, of course, her glucocorticoid levels, went
very, very high and she embarked on a kind of grooming campaign to try to
identify a new grooming partner. Nobody would have her. Every time she
approached anybody, animals would run away from her. And so she spent the
last few years of her life pretty lonely.
And then this past May at the age of 25 she was seriously injured by a leopard
and she spent weeks off on her own trying to recuperate and finally did.
During this time, some of the low-ranking animals began to try to challenge
her and try to, you know, oust her from her relatively high-ranking position,
at which point her sister, who otherwise hadn't been paying attention to her
for years, supported her and re-established her bond and refused to let her
fall in rank and so on. So we all had a great attachment to Sylvia and when
she recently died, I was e-mailing all of our former post-docs and everybody
wrote back saying, `Oh, Sylvia.'
One of the interesting thing is about these animals is that you don't try to
anthropomorphize, but everybody kind of agrees on different individual's
personalities, so it's interesting that these personalities really emerge
consistently.
GROSS: Hm. During the last few years, while you've been pursuing your
research, there's been a lot of controversy in the United States about whether
evolution should be taught in schools or intelligent design. Having spent so
many years of your life devoted to researching primate behavior and primate
communication, what do you make of the fact that evolution became
controversial again in the United States?
Mr. SEYFARTH: Well, I guess as biologists we always regard this controversy
with a bit of disbelief. I mean, evolution is the dominant organizing theory
that organizes what we do in the biological sciences, and that includes the
biomedical sciences as well. So many of the medicines we use, the pesticides
we use, we make decisions about whether they're appropriate for humans based
on comparative tests with animal studies that are based on the premise that
animals are like us in many respects because of evolution. We can reproduce
evolution in the laboratory. And in fact, it's particularly odd just as we're
beginning to know more and more about the relationship between genetics and
behavior and physiology, all of a sudden the theory that guides us in those
investigations becomes controversial, it's a little bit surprising.
GROSS: I want to thank both of you so much for talking with us about your
work. Thank you.
Ms. CHENEY: Thank you.
Mr. SEYFARTH: You're welcome.
GROSS: Dorothy Cheney and Robert Seyfarth are the authors of "Baboon
Metaphysics." They're both professors at the University of Pennsylvania.
You can download podcasts of our show on our Web site, freshair.npr.org.
(Credits)
GROSS: I'm Terry Gross.
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