TO THE GALAPAGOS"
Lizards of the Sea
ALAN ALDA: Charles Darwin once rode on one of these. And it
was something about their shells that gave him the first clue
that living creatures change over time.
ALAN ALDA (Narration): The giant tortoises of the Galapagos Islands
are among the many unique animals here…
ALAN ALDA: OK, I'm sorry, I'm sorry.
ALAN ALDA (Narration): …that got Darwin to thinking about how new
species come into being. Today, the islands' creatures still
amaze their visitors…and provide insights into how evolution
ALAN ALDA: I'm Alan Alda. Join me, and the creatures that inspired
Darwin, as we Voyage to the Galapagos.
ALAN ALDA: In 1831, at the age of 22, Charles Darwin set off on
a voyage that would change not only his life but ours as well.
The naturalist on the British Naval ship The Beagle, Darwin
traveled around South America and beyond. What he saw on an
isolated group of islands out here in the Pacific began an
intellectual voyage that would last some 20 years, and would
culminate in the then shocking idea that living things are
not designed according to an unchangeable plan, but instead
are shaped by the world around them. When the Beagle finally
anchored here in the Galapagos in September of 1835, Darwin
was very excited about coming here. He was really fascinated
with the geology of the place, particularly the volcanic origin
of these islands. But when he actually set foot on the shore,
he was very disappointed in this place. In fact, this is what
he wrote: "Nothing could be less inviting than the first appearance.
A broken field of black basaltic lava is everywhere covered
by a stunted brushwood, which shows little signs of life.
The dry and parched surface, having been heated by the noonday
sun, gave the air a close and sultry feeling, like that from
ALAN ALDA (Narration): Six hundred miles off the South American
coast, the Galapagos Islands are actually the tips of volcanoes
that have pushed their way above the ocean surface. The oldest
islands were formed some 2 - 3 million years ago. The youngest
-- including the biggest, Isabela -- are a few hundred thousand
years old -- with volcanoes that still erupt. My visit to
the Galapagos is to take me to over half the dozen or so major
islands -- including one whose volcanic origins are only too
ALAN ALDA: These rocks look like they're laid out in a circle.
FOWLER: Yeah, this is Devil's Crown. It's an old eroded crater
that's very shallow here in the middle.
ALAN ALDA: We're in the middle of a crater, a volcanic crater?
LYNN FOWLER: Yeah, it's not going to erupt though, don't worry.
ALAN ALDA: How do you know?
FOWLER: It's old. It's all eroded.
ALAN ALDA: A lot of old
things erupt. Me! I'm really surprised at how lush it is…
ALAN ALDA (Narration): My guide on the trip is Lynn Fowler, a biologist
who has spent much of her life in the islands.
What is this trail?
FOWLER: Oh, that's a land iguana trail.
ALAN ALDA: So at the end of this trail we might find an iguana?
FOWLER: We might find one. Let's see…
ALAN ALDA (Narration): And here, as if waiting patiently for our
arrival, is a creature that Darwin was not immediately impressed
ALAN ALDA: When Darwin first saw these land iguanas, he thought
they looked slow and stupid. In fact, there's a funny story
he tells about that. Darwin was watching a land iguana burrow,
making a hole somewhat like this one. And Darwin gave the
tail a little yank. And the iguana backed out of the hole
and looked at him, as if to say, "What did you do that for?"
ALAN ALDA (Narration): What Darwin interpreted as stupidity in
the islands' land iguanas is in fact an extraordinary indifference
to humans that's shared by all the Galapagos animal life --
and that Darwin repeatedly noted in his account of his voyage.
He took advantage of it in his several encounters with the
Galapagos Islands' most famous residents, the giant tortoises.
ALAN ALDA: "As I was walking along I met two large tortoises,
each of which must have weighed at least two hundred pounds.
These huge reptiles, surrounded by the black lava, the leafless
shrubs, and large cacti, seemed to my fancy like some antediluvian
animals. I was always amused when overtaking one of these
great monsters, as it was quietly pacing along, to see how
suddenly, the instant I passed, it would draw in its head
and legs, and uttering a deep hiss fall to the ground with
a heavy sound, as if struck dead. I frequently got on their
backs, and then giving a few raps on the hinder part of their
shells, they would rise up and walk away; -- but I found it
very difficult to keep my balance".
ALAN ALDA (Narration): Today, visitors to the Galapagos usually
pay their respects to the handful of giant tortoises that
are housed at the research station here named for Charles
Darwin -- though getting to feed them is a privilege reserved
for the foolhardy.
ALAN ALDA: My problem is I not only saw ET, I also saw Jurassic
ALAN ALDA (Narration): In Darwin's day, the giant tortoises were
still being hauled away by the thousands to provide fresh
meat for whaling ships.
ALAN ALDA: That's a little too close to my fingers, you can have
ALAN ALDA (Narration): The governor of the Galapagos told Darwin
that he could tell by the shape of its shell which island
a tortoise came from. This saddle-backed tortoise, for instance,
comes from the island of Espanola. At the time, Darwin paid
little attention to the Governor's claim. But it was to be
the foundation for everything that followed. Soon he saw for
himself how creatures could be recognizably different from
one island to the next. These mockingbirds, like the saddle-backed
tortoise, are from the island of Espanola.
ANDERSON: These mockingbirds are having a flick fight. They
flick their tails and wings back and forth. It's a territorial
display between two big groups of mockingbirds that are families,
and they're disputing what's going on at the territorial boundary.
So they do this big display saying, you know, if you cross
over this boundary, this is what's going to happen to you.
It's going to be bad.
ALAN ALDA (Narration): Dave Anderson is one of the few biologists
with permission to come to the Galapagos year after year to
pursue his research. The rules governing his visits are strict
-- and everything he brings in must go out. Mockingbirds are
a constant presence in his camp on Espanola, and they seem
eager to volunteer for a show-and-tell.
ANDERSON: On this island, the mockingbird species is larger
than on other islands, and on this island the beak is long
and curved, they use that to move dirt around, they dig more
on this island than on other islands. Also the breast feathers
are whitish and speckled and some of the other species are
much cleaner in the breast. The point is that nearby islands
have very different looking birds. It's no problem for even
an amateur birder to know the difference between species of
ALAN ALDA (Narration): In addition to the Espanola mockingbirds,
two other islands have their own distinct species. Then there's
a fourth species, common across most of the islands -- including
here on the northeasternmost island, Genovesa.
ALAN ALDA: They all look a little different, depending on the island
they come from?
DAVE ANDERSON: Yeah, so for example, those Espanola birds
had a lot of speckling on their breasts, and this one doesn't,
this one's got a clean white breast. Looks cleaner all around.
Those Espanola birds look sort of ratty and dirty.
ALAN ALDA: You're going to let him go?
ANDERSON: We can try hypnotizing him.
ALAN ALDA: Can he fly if he's hypnotized?
ANDERSON: He'll go to sleep.
ALAN ALDA (Narration): Mockingbirds joined the giant tortoises
on Darwin's list of creatures that for some mysterious reason
were slightly different on different islands.
DAVE ANDERSON: I will now make this mockingbird wake up.
ALAN ALDA: You didn't even give him a post-hypnotic suggestion!
ALAN ALDA (Narration): During his five weeks in the Galapagos,
Darwin visited only four of the islands… yet he managed to
collect hundreds of specimens of birds, animals and plants.
FOWLER: Ciao Henry.
ALAN ALDA: This was one of the islands Darwin landed at?
FOWLER: Yeah, this is Floreana. It was his second stop, actually,
in the Galapagos.
ALAN ALDA (Narration): By now, Darwin was becoming increasingly
excited by the natural history of the islands. Everywhere,
he was seeing what he called "aboriginal creations", animals
and plants found nowhere else, what biologists now call endemic
species. On Floreana alone, he identified 21 endemic plants.
ALAN ALDA: So what plants here are endemic to this island?
FOWLER: Here we've got Lecocarpus, this little yellow daisy.
And this here with the hairy leaves, this is Scalesia delosa.
ALAN ALDA (Narration): And once again, Darwin noticed that different
islands had their own unique versions -- including a species
of Scalesia that grows into a 30 foot tree. But there was
something else besides the uniqueness of the plants and animals
here. They seemed to Darwin to bear a striking resemblance
to those he'd just seen in South America. And a tremendous
idea began to germinate: perhaps here in the Galapagos he
was close to nothing less than the origin of species.
ALAN ALDA: "The natural history of these islands is eminently curious,
and well deserves attention. Most of the organic productions
are aboriginal creations, found nowhere else; there is even
a difference between the inhabitants of the different islands.
The archipelago is a little world within itself, or rather
a satellite attached to America, whence it has derived a few
stray colonists…. Hence, both in space and time, we seem to
be brought somewhat near to that great fact -- that mystery
of mysteries -- the first appearance of new beings on this
ALAN ALDA (Narration): It would be two more years, the Beagle's
voyage finally over, before the "mystery of mysteries" began
to resolve itself in his mind. It happened as he was puzzling
over another group of creatures that, while he was here, he
hadn't paid much attention to -- the little birds now called
Darwin's Finches. back to top
ALAN ALDA: And this goes down, right?
ALAN ALDA (Narration): We're setting up a mist net to catch one
of the group of birds that has become literally synonymous
with Darwin and his theory of evolution.
ALAN ALDA: This needs to be loose like this?
ANDERSON: Yeah, what happens is the bird flies in and doesn't
see it, and so it carries the net out with it with its momentum
and then sags down hanging like this in a little bag.
ALAN ALDA AND DAVE ANDERSON: Pssht, pssht, pssht.
ALAN ALDA: Can they hear that?
ANDERSON: You can also go like this: squeak, squeak.
ALAN ALDA: You do that when you've been here too long?
ANDERSON: Birders act like they know what they're doing and
they make this little squeaky sound and they all pretend like
it's making a difference. I don't know whether it does or
ALAN ALDA: Pssht, phsst. You got one, you got one!
DAVE ANDERSON: It's a sharp-beaked ground finch!
ALAN ALDA (Narration): Our bizarre calls have netted us a bird
from one of the 13 different species of finches in the Galapagos
-- birds that are today known collectively as Darwin's Finches.
ALAN ALDA: Now what is this again?
ANDERSON: This is the sharp-beaked ground finch. This is the
smallest ground finch on this island. It's got a pointy little
beak that's great for grass seeds.
ALAN ALDA (Narration): Today, Darwin's finches are in all the textbooks
as the classic example of how living things adapt to their
environment. Each of the 13 species in the Galapagos has a
different beak that suits its lifestyle -- from feeding off
cactus flowers to using twigs to dig out insects from the
bark of trees. A group of species known as ground finches
are the most common. This is the large ground finch, with
a thick, heavy beak perfect for cracking open large tough
seeds. The sharply-beaked ground finch, by contrast, eats
mainly small seeds.
ANDERSON: If you gave this guy a gram of small seeds to eat,
it would get done a lot faster than this guy.
ALAN ALDA: Because he's got too much beak in the way?
ANDERSON: He's got too much equipment, it's big and bulky.
He can handle it but not fast enough.
ALAN ALDA: So he'd have to spend more energy on feeding himself
and he needs the energy to do it.
ANDERSON: Yeah, his net intake would probably be negative.
ALAN ALDA: So although he could be eating all day long he could
eventually starve to death.
ANDERSON: Yeah, he's got expenses, overhead he's got to pay…
ALAN ALDA: Yeah, too much overhead…
ANDERSON: And you look at the body sizes and he's got more
overhead than this one.
ALAN ALDA (Narration): Contrary to legend, Darwin himself didn't
pay much attention to the dull little birds that often hopped
around his feet. He collected several dozen while he was here,
but didn't even bother to label them or note which island
they came from. But by a delicious twist of fate, it's the
finches on one of the Galapagos Islands -- an island that
Darwin didn't even visit -- that have become the single best
proof that his theory of evolution is no longer only a theory
but an observable fact. As we approach the island, I can see
why Darwin never landed here.
ALAN ALDA: You mean, on the face of that cliff.
ANDERSON: Right there, yeah, it looks a little worse from
here than it really is. Or perhaps not.
ALAN ALDA: It's not only a cliff. The cliff sticks out on the top!
ALAN ALDA (Narration): The island -- called Daphne Major -- is
only a mile or so across. For some quarter century now a team
of biologists, and a string of graduate students -- including,
briefly, Dave Anderson -- have been coming here every year.
ANDERSON: Alright! This guy's like a spider!
ALAN ALDA (Narration): The researchers single purpose has been
to weigh and measure every one of the few hundred ground finches
that share this lump of volcanic rock with low, rather scrubby
vegetation, some seabirds and not much else -- apart from
the occasional grumpy sea lion.
ALAN ALDA: Just passing through. Why do people go to all this trouble
of getting on this thing? What's the significance to science
of Daphne Major?
ANDERSON: Well, there are some folks who call Daphne Major
the laboratory of evolution. It's a really great place to
see evolution actually happening because the system, the biological
system, is relatively simple. Not too many components and
for the finches it kind of boils down to what seeds are here
and what tool do I have to crack those seeds.
ALAN ALDA (Narration): The main ground finch here is about halfway
in size between the two species Dave and I looked at earlier.
What the researchers have found is that when small seeds are
plentiful -- usually in rainy years -- the beaks of the birds
born the following year are also, on average, smaller. When
there are plenty of large seeds, in drier years, the next
generation has beaks that are larger. This is evolution. And
it's driving force -- Darwin's great insight -- is natural
selection. Here's what's happening. In every generation of
finches, there's a range of beak sizes, some a little smaller
than the average, some a little larger. When small seeds are
plentiful -- when there's been plenty of rain -- the smaller-beaked
birds are the more efficient eaters. So they thrive and produce
more offspring than the larger-beaked birds. The result is
that in the next generation, there are more small than large-beaked
birds. The average beak size is smaller than the last generation.
The population has evolved. When conditions change, and a
dry year brings more large seeds than small, then large-beaked
birds do better. They leave more offspring, and the population
shifts toward a larger average beak size. Smaller to larger,
larger to smaller. It's these subtle shifts in beak size that
the researchers here have so meticulously documented.
ANDERSON: The really significant thing they found is that
oscillation back and forth, the size of the beak really does
change over short periods of time. And they know exactly why.
It's because their food supply changes.
ALAN ALDA: And that's a case of actually seeing evolution in progress,
to see it as it happens?
ANDERSON: Yeah, yeah, the really cool thing about this, for
everybody, scientists and everybody else, is that there's
no question that it is evolution happening in front of our
eyes. We don't have to think of evolution as something we
only get from the fossil record or theorizing about. You can
go to a place like Daphne Major, where it's simple, and you
can actually see evolution happening almost on a monthly basis,
certainly an annual basis.
ALAN ALDA: You know, it's interesting, I've often heard people
say -- people sympathetic to the idea of evolution -- that
you have to take a little bit of it on faith. But you don't
have to take any of it on faith?
ANDERSON: Not any more. Not after this study.
ALAN ALDA (Narration): It's wonderfully appropriate that evolution
should move from theory to fact in a study of Darwin's Finches
… because it was while Darwin himself was trying to make sense
of his haphazard finch collection that the idea of evolution
first occurred to him. With it, he could explain not only
why different islands have different finches -- but also different
mocking birds -- different plants -- different tortoises.
From the time their ancestors arrived in the archipelago,
the animals on different islands have gone their own independent
ways, shaped by the conditions they found themselves in, until
eventually they became -- different species. As for how their
ancestors got here -- well, we're coming to that…
OF THE SEA
ALAN ALDA (Narration): Getting here was no problem for the ancestors
of the Galapagos sea lion. Lynn Fowler has promised me an
underwater rendezvous with a sea lion pup -- and, this being
the Galapagos, there's an eager volunteer. The Galapagos sea
lion, like most of the creatures here, has changed since it
arrived, evolving into a smaller version of its California
ALAN ALDA: I saw his face like this, and it's like, so what are
you going to do, what do you want to do?
ALAN ALDA (Narration): Sea lions can swim. But how did land animals
get here way out here in the Pacific Ocean? The explanation
I've heard was that they came on floating rafts of vegetation.
But iguanas and tortoises are hefty creatures.
ALAN ALDA: So they had to have had a pretty hefty raft to get here.
FOWLER: Well, there are big chunks of land that come down
some of those rivers on the South American continent. And
they float way out here, 600 miles.
ALAN ALDA: An actual chunk of land? I thought it was just like,
you know, twigs or branches.
LYNN FOWLER: No, there are chunks of land that even have standing
trees that have been seen floating way out to sea in the ocean.
And those could easily bring several species at once to a
system like this.
ALAN ALDA (Narration): Of all the immigrants here, few have adapted
so successfully to island life as the marine iguanas. Wherever
you go along the shoreline, iguanas will be on display --
ALAN ALDA: He's green on the top and red along his body. What
FOWLER: Yeah, that's a breeding male. That's the color that….
ALAN ALDA: Oh, that's a signal he's ready to breed?
FOWLER: That's right. He'll set up a territory and try to
attract some female to it. So that's a big breeding male.
Beautiful, isn't it?
ALAN ALDA: What does he do to attract females? Oh the head-bobbing
thing. Kind of cool….
FOWLER: Right. Look, I can do 20 push-ups, I'm the man for
you! He's a beauty though, isn't he? Doesn't that look like
ALAN ALDA (Narration): Charles Darwin, had he ever heard of Godzilla,
might have agreed.
ALAN ALDA: "It is a hideous-looking creature, stupid, and sluggish
in its movements…. When in the water this lizard swims with
perfect ease and quickness, by a serpentine movement of its
body and flattened tail -- the legs being motionless and collapsed
by its sides. I opened the stomachs of several, and found
them largely distended with minced sea-weed."
ALAN ALDA (Narration): Darwin put his finger on just those
adaptations that have made the marine iguana fit so perfectly
into its island home.
ALAN ALDA: All he wants are his greens, uh? I mean, vegetables….
FOWLER: Yeah, all that sea lettuce, ova, is his favorite food.
ALAN ALDA (Narration): The ancestors of these creatures were like
all the other lizards in the world, swimming only when they
ALAN ALDA: He made it, up the cliff.
ALAN ALDA (Narration): But the Galapagos marine iguanas, as their
name implies, have turned to the sea to sustain them, eating
as virtually their only food the bright-green algae that grows
all along -- and beneath -- the shoreline. Not only have they
become expert swimmers. They have also developed the ability
to digest the algae with the help of a bacterium that lives
in their hind-gut. This specialization has made the marine
iguanas the lords of the seashore. But it has also left them
extremely vulnerable. Martin Wikelski has witnessed their
vulnerability first hand.
ALAN ALDA: What was this like during that last great El Nino?
WIKELSKI: Well, it was horrible. Those guys are about ten
percent of all the animals that were here….
ALAN ALDA: There were ten times as many?
WIKELSKI: Ten times as many. And they were going to forage;
they were trying to get the last bits of algae, and then slowly
walking up the beach. So they would just put one foot forward
and still try to go up but then really bake in the sand literally.
And they just all died in front of our eyes. So we had I think
we had like 400 dead animals in just a few weeks. Pretty amazing.
ALAN ALDA: Now was that because all this green we see here was
WIKELSKI: Yeah. All this green you see was totally black.
There was absolutely nothing growing on these rocks.
ALAN ALDA (Narration): The cause of the devastation was the 1997-98
El Nino, a plume of unusually warm water that wreaked havoc
with weather patterns all over the globe. Its impact on the
Galapagos was more direct, bathing the islands in warm water
and driving out the cold nutrient-rich currents that normally
sustain the marine life here. Everything on and around the
islands that lives off the sea suffered. But the marine iguanas,
whose sole food source withered away, suffered the most. But
it turns out that even during good years, the marine iguanas
here on the island of Genovesa have to struggle to make a
ALAN ALDA: Why do we see so many smallish iguanas here?
WIKELSKI: Right. This island gets the least of the nutrients.
And that means that this algae -- you probably saw iguanas
ALAN ALDA: Yes
MARTIN WIKELSKI: They sometimes have these huge algae pastures,
and they just get a mouthful of algae every bite. But here
they only have a tiny little carpet of algae and they constantly
have to scrape it off.
ALAN ALDA: So that selected out the big ones.
WIKELSKI: Right, absolutely.
ALAN ALDA: The big ones that might be born here just aren't going
to get enough nutrients.
WIKELSKI: Yeah, absolutely.
ALAN ALDA: That's interesting. So there they are. That's the product
of natural selection right there.
ALAN ALDA (Narration): But even among these smaller-than-average
animals, some of the males are clearly larger.
ALAN ALDA: This big guy has walked through the entire collection,
doing that nodding thing to announce his territory, right?
But is he the only one in this whole batch that's dominant
WIKELSKI: He's the hot shot. He's definitely the prize male,
because you see all these females around here? They all like
to hang out with him. So the females are the ones that choose
in this system, and the males try to do their best to get
ALAN ALDA: The females are attracted to this big handsome
guy -- this ugly thing here, but….
WIKELSKI: He's not ugly!
ALAN ALDA: I know you come here every day and you kind of like
the way they look now. But I'm telling you, I just got here
WIKELSKI: You should be here 30 days and you'll like them.
ALAN ALDA: Yeah, OK, OK.
ALAN ALDA (Narration): Yes, Martin actually does spend the entire
30 days the iguanas here are deciding on mates, watching to
see which males the females pick. It's an important decision.
WIKELSKI: Each of these females only has one egg. It's absolutely
amazing, they have about 25% of their body mass in one egg.
ALAN ALDA: So it really counts who they choose.
ALAN ALDA (Narration): Martin is trying to understand why, if the
big guys are so popular, the group here also contains a number
of much smaller males, who instead of showing off keep a deliberately
MARTIN WIKELSKI: See that guy? He was sort of sneaking up
on the female, trying to get her. That's one of these small
sneaker males that hang out in the territory (and they try
to sort of sneak up on the females). They're about the females'
size, so the male can't tell them from females. So they just
try to sneak up on females and try to mate with them, if they
ALAN ALDA: So in a way he gets an advantage. He gets a chance to
sneak up because he's a female impersonator right up until
the last moment.
MARTIN WIKELSKI: Right.
ALAN ALDA (Narration): There must be some reason the females accept
the sneakers or natural selection would have long since have
eliminated them. Martin's hypothesis is that keeping smallness
genes around provides the females with a sort of insurance
policy against those brutal El Nino years, when being big
can be fatal.
WIKELSKI: That seems to be a sort of long-term strategy. They
can't really know when the next El Nino hits, so sometimes
they might choose a small male as a mating partner to have
smaller offspring, and sometimes they might choose a bigger
ALAN ALDA: One year you try it big, one year you try it small,
and you protect yourself all the way around. He's not going
to mind this, coming in his face…?
ALAN ALDA (Narration): In the course of testing his insurance idea,
Martin has caught thousands of marine iguanas here on Genovesa.
The least I can do is lend a hand with one.
ALAN ALDA: Now he's probably on to this. He's not going to like
this at all.
WIKELSKI: Ah, that's a good one. Excellent.
ALAN ALDA: I had good beginner's luck.
ALAN ALDA (Narration): This iguana was first caught and marked
by Martin when it was a hatchling. Twelve years later, it's
one of the kings around here.
WIKELSKI: But if another El Nino comes and the guy's too big,
then we basically find his body on the beach someday. This
is the first one of the season, so we'll give him an "A."
ALAN ALDA (Narration): The paint will make it easier to keep an
eye on him.
ALAN ALDA: Is it possible that this will turn out to be some cue
to the females that this guy should be avoided at all costs?
WIKELSKI: That's a good point.
ALAN ALDA: Do they take any visual cues?
WIKELSKI: Many people at conferences ask me, and we did test
it, because we know that in other lizards it would make a
big difference. But in those guys it doesn't. So the females
don't go for coloration, they don't care about the markings
we put on them, and they probably only go for the size and
for the behavior.
ALAN ALDA: Yeah, but this guy is now clearly a movie star. Aren't
they going to notice that?
WIKELSKI: That is true. So that's it for this guy. I can let
ALAN ALDA (Narration): Martin Wikelski isn't the first scientist
to catch and release marine iguanas here in the Galapagos.
ALAN ALDA: "I threw one several times as far as I could, into a
deep pool left by the retiring tide; but it invariably returned
in a direct line to the spot where I stood…. Perhaps this
singular piece of apparent stupidity may be accounted for
by the circumstance, that this reptile has no enemy whatever
on shore, whereas at sea it must often fall a prey to the
numerous sharks. Hence, probably, urged by a fixed and hereditary
instinct that the shore is its place of safety, whatever the
emergency may be, it there takes refuge."
ALAN ALDA (Narration): Late one afternoon, Lynn and I found ourselves
stepping carefully to avoid marine iguanas lounging before
bedtime all over the waterfront of the island of Fernandina.
LYNN FOWLER: Oops, almost stepped on its tail.
ALAN ALDA (Narration): I remember my surprised and delighted reaction
to the first marine iguana I saw only a few days ago. But
already they've become simply a part of the place. But just
watch them for a while. What an extraordinary story they tell.
For hundreds of thousands -- perhaps millions -- of years,
they've lived and died here, slowly sculpted by that living
and dying from the land creatures they once were into the
imperious masters of their new marine environment. It's a
story that, for one giddy moment, it seems to me they deserve
LYNN FOWLER: No, I'm serious. There's this guy Charles Darwin
who says it's so. Look, you have to believe me. You all descended
from some lizard, a long time ago. Can I see a show of claws?
Who believes that?
ALAN ALDA (Narration): I should have known from my first encounter
with a bird called the masked booby that this is a creature
with a strange sense of right and wrong.
ALAN ALDA: OK, OK, OK!
FOWLER: We got a little close to the guano ring there.
ALAN ALDA (Narration): My second encounter came in the company
of Dave Anderson.
ANDERSON: All right, Alan. Here we've got a nestling masked
booby with its parent who has conveniently stepped aside so
we can put a band on its chick.
ALAN ALDA (Narration): Dave has been studying masked boobies for
half his life -- trying to understand a singularly gruesome
ANDERSON: We gently grab the bird.
ALAN ALDA (Narration): …that this young booby, all fluffy and apparently
innocent, may well have committed murder.
ANDERSON: This is maybe a 35, 40 day old masked booby chick,
and it can give you a good nip. So if you would like to hold
ALAN ALDA: It can give you a good nip so if I would like to hold
it. Is that like an actual sentence?
DAVE ANDERSON: Now don't squeeze it. Get up around the head…
ALAN ALDA (Narration): Not only is this baby booby a natural born
killer. The creature it may have killed was its own sibling.
ANDERSON: We're going to give this bird a name. Probably already
has a name but this is what I'm going to call it: 95289.
ALAN ALDA (Narration): Dave Anderson wants to know why the murder
occurred. Even more, he wants to know why the parents did
nothing to stop it.
ANDERSON: And we'll put this little chick back in its home.
The chick needs to calm down. There.
ALAN ALDA (Narration): To answer these questions, Anderson has
been coming here to the island of Espanola for 20 years. Masked
boobies breed in colonies -- and things start off romantically
ANDERSON: Some of these birds don't have a mate. And so when
they're trying to find one, they check out different possibilities.
And they get together and they maybe have a date for an afternoon
where they give each other little gifts -- twigs, stuff like
that -- and if they're not compatible they'll know pretty
quickly, and if they are compatible maybe they'll continue.
It's a lot like a species we know pretty well. Most birds
in other species make a nest and masked boobies don't. But
the building of a nest and the accumulation of materials,
showing what a great twig you've got is still part of the
ritual. So it's another way of saying, "I'm in the family
way, are you, do you like this twig, maybe if we like the
same kind of twig we might be able to get together…."
ALAN ALDA (Narration): But once the wedding bells have rung,
the harsh reality of masked booby family life begins.
DAVE ANDERSON: This parent has two chicks under it. One of
them hatched about seven days ago, and the other one hatched
out of this eggshell about two days ago. When the second chick
hatched it was a smaller size and less capable, and the first
chick is going to push this helpless second chick out of the
nest, if it behaves like normal masked booby chicks.
ALAN ALDA (Narration): For the first few days, the chicks
amicably share their nest. But on day five, things turn nasty.
Apart from food, the main thing the parent is providing for
the chicks is shelter from the glaring sun. The older chick
is trying to push the younger out from the shade -- to a slow
but certain death. Throughout the struggle the parent remains
aloof and apparently indifferent.
ANDERSON: The parent is not going to do anything about this
siblicide, we call it siblicide, the killing of a sibling.
If it's like most masked booby parents it will simply watch
or look around or do something else, but it will not help
this poor offspring that's being killed by its own sibling.
The first time I saw this happen, I couldn't believe what
bad luck the B chick had. Its closest relative in the world
is throwing it out of the nest to die on the hot ground of
sunstroke. It's sort of a miserable thing to see. I've seen
it enough times now that I accept that that's the normal way
of booby life. But it is kind of shocking the first time you
ALAN ALDA (Narration): Shocking -- and in Darwinian terms, baffling
-- at least at first sight. After all, that's the parent's
own genes lying there dying.
ALAN ALDA: I don't understand the economics of this. If she's going
to lay two eggs, and everybody knows that the first one is
going to kill the second one, why expend all that energy,
to lay a second egg?
ANDERSON: It seems like a waste.
ALAN ALDA: Yeah.
ANDERSON: In terms of natural selection, selection is going
to maximize the excess benefit over the cost. Certainly the
benefit has to exceed the cost. In this case, there's a benefit
to laying the second egg because they have lousy hatching
success. They only hatch about 60% of the eggs, even if you
eliminate accidents and stuff. Something about fertility or
embryo development causes 40% of them to die. So if you're
going to get one chick, gotta have one chick, you're prepared
to pay the price of a second egg, even though it's expensive,
because if the first one fails, the second can take its place.
ALAN ALDA: It seems to me that once you've gone to the trouble
of laying two eggs, and you have a good shot at having two
healthy adults come out of that, isn't your purpose better
served to let both of them live?
DAVE ANDERSON: Yeah, good question. If you experimentally
stop the siblicide from happening, and make them play nice,
and then challenge the parent to bring back enough food for
two, about 30% of the time, they can do it. She doesn't stop
feeding. If there are two chicks in front of her, she'll feed
'em, you know, open mouth, put in food, that's what she does.
And if there are two of them there, she'll put it in at twice
the rate. So you say, well, they definitely should be stopping
the siblicide from happening. However, if you follow those
parents another year, you find out in the year after they
raised two chicks, they take it on the chin in terms of survival.
Particularly the moms. Regular moms survive at about 92%,
from year to year. And the experimentals, that have had to
raise two chicks, survive at about 75%. And that's a huge
ALAN ALDA (Narration): A cost that in terms of natural selection
simply cannot be sustained.
ALAN ALDA: This is really fascinating. But on the other hand, I'm
spending just a few hours talking to you about this, and you're
spending your life on it. How did you get led to that?
ANDERSON: It's a problem that on the surface seems fairly
easy to address, the problem being, why lay that second egg,
given that you lay the second egg, why not try to raise two
chicks. But to actually look at how selection acts on the
individual, you really ought to have a long-term perspective.
And following the lifetime consequences of a long-lived animal
may take up most of your career. Some of the birds that I
have initiated a study of as babies are going to outlive my
ALAN ALDA (Narration): But many won't. Even chicks that have
won the battle of the nest fall prey to mockingbirds, pecking
them for their blood. And then there are the constantly marauding
frigate birds, always looking to snatch a chick from its nest.
ANDERSON: I mean you either get killed by your sibling and
your parents don't care. Or if you manage to survive that
process, then when your parents leave you alone a frigate
bird might come down and drop you from a hundred feet in the
ALAN ALDA (Narration): Dave Anderson's life among the masked boobies
of Espanola has given him unusual access to the daily struggle
that drives evolution. And it isn't a pretty sight.
ANDERSON: Life stinks for most organisms most of the time,
and we maybe don't realize it so much looking at continental
systems as opposed to here, because here the animals do their
suffering out in the open. Particularly these boobies. They
just have a miserable life you wouldn't wish on your worst
enemy. All these terrible thing that can happen to you. And
it's really apparent to us because they're not hiding it.
They don't have a history of trying to hide from creatures
like us, and they just do it in front of us. We can sort of
participate in the community as a kind of ignored observer,
walking down the back alleys of their lives, and they sort
of let us do it.
ALAN ALDA (Narration): Among the more recent immigrants to the
Galapagos are humans. When Darwin came in 1835, people lived
scattered in small fishing and farming communities throughout
the archipelago. With people came animals that would never
have made here it on their own: chickens, dogs, cats; goats,
pigs, cattle. Today, there are strict rules governing where
people and their animals can live. Ninety-six per cent of
the land is National Park, off-limits to anyone not accompanied
by a guide like Lynn Fowler. But while people can be controlled,
the animals they've brought with them can't. We're climbing
a peak overlooking Santiago, one of the four islands on Darwin's
FOWLER: When Darwin camped there….
ALAN ALDA: That's all Santiago over there?
FOWLER: Yeah…there were so many land iguanas on it that he
could hardly find a place to pitch his tent, because of the
land iguana burrows. But, they're extinct now. They're extinct
ALAN ALDA: Really? How did that happen?
FOWLER: Dogs and pigs -- and rats. They go right in….
ALAN ALDA: Rats attack the iguanas?
FOWLER: They go right in to the land iguana burrows and eat
the eggs and kill the hatchlings.
ALAN ALDA (Narration): One of the Galapagos natives worst hit by
humans and the animals they brought with them is the giant
tortoise. Originally decimated by whalers hauling them off
for food, they have since had to compete with pigs and goats
that have gone wild and run rampant over many of the islands.
Thirty years ago, the population of the characteristically
saddlebacked tortoises of Espanola was down to just 13 --
12 females and a male. Brought here to the Charles Darwin
Research Station on the island of Santa Cruz, these 13 tortoises
-- aided by a second male recruited from the San Diego Zoo
-- have since produced hundreds of offspring. Lavishly fed,
and kept safe from rats until their shells are strong enough
to protect them, the youngsters here can look forward to a
ALAN ALDA: Don't be shy. How old is he?
HERMAN: This one's about a year and a half old.
ALAN ALDA: And how old will he get to be if he's lucky?
HERMAN: Well, we can guarantee that they'll live to between
60 and 90 years old. But history books and stories that are
a bit difficult to confirm say anything up to 150, 200 years.
ALAN ALDA (Narration): The project owes its success largely to
this man, Cruz Marquez, who with his colleagues has had to
invent the captive breeding process as they went along. A
critical realization was that the sex of the hatchlings depends
upon the temperature at which the eggs are incubated -- 29.5
degrees Celsius gives you females, 28 degrees Celsius and
you get males.
ALAN ALDA: Sounds like you must have to have a pretty sophisticated
system here to keep the temperature what you need it to be.
HERMAN: We have an incredibly sophisticated system. We have
a hairdryer, connected to a thermostat here, on continuous
ALAN ALDA (Narration): Despite the shoestring budget, the captive-breeding
program has resulted in some 800 Espanola tortoises being
returned to their native island. Making this possible was
an ambitious -- and successful -- program aimed at ridding
the island of goats, the tortoises' main competitor for resources.
But many of the islands -- including the biggest, Isabela
-- remain over-run with goats as well as pigs. Their eradication
is a principle goal of people trying to preserve the islands'
unique biological heritage -- people like the Darwin Research
Station's Howard Snell.
SNELL: We're coming into Elizabeth Bay off the coast of Isabela,
the largest island in the Galapagos. And these are the Marielas
ALAN ALDA (Narration): But for some introduced species, eradication
is all but impossible. Rats, for instance, have been in the
Galapagos as long as ships have visited here. They appear
to have invaded the Marielas Islands only recently -- but
now may be threatening one of the Galapagos' most unexpected
SNELL: Penguins in the Galapagos Islands are the northernmost
penguins in the world. So, it's a unique kind of penguin.
But unfortunately, the penguins in Galapagos aren't doing
particularly well. When El Nino events come in to the archipelago,
which happens every so often, the water gets very very warm,
and the normal fish life around here begins to die off. When
that happens, penguin populations crash. In 1982-83, they
crashed by over 50%. This year, 97, 98, they crashed again.
And the thing that confuses us is they don't recuperate after
those crashes. Now that worries us because of course if populations
crash every so often and never recuperate, they can go extinct.
ALAN ALDA (Narration): Howard suspects rats are the culprits, invading
the rock crevices where penguins lay their eggs and raise
their chicks. So he's conducting an experiment to see what
can be done to save the penguins -- short of the impossible
task of ridding the Galapagos of rats entirely.
SNELL: Now what we're trying to do is to use these islands,
these small islands, as models for the rest of the Galapagos.
And we're removing the rats, by poisoning them, from some
of the islands and leaving them on others. The idea is to
try and measure how few rats we can remove to increase penguin
reproduction. That way we can invest enough money to increase
penguin reproduction, but not so much money that we can't
do other things also. It's really about trying to divvy up
limited resources for the conservation of the biology of the
ALAN ALDA (Narration): Those resources may become a little less
limited in the future, thanks to the latest alien species
to invade the Galapagos Islands -- ecotourists, who come by
the thousands each year. These tourists bring in millions
of dollars for the tour operators, but until recently little
or nothing for the wildlife. Now that's changing.
LINDBLAD: There are about 60,000 people a year who visit the
Galapagos, and I'm of the belief that those 60,000 people
can be a major part of the future of these islands. Companies
like ourselves who benefit and indeed profit from being able
to bring these visitors here are in a position to be able
to make a difference. And in the last year, in the year since
we've been here, we've raised about a couple of hundred thousand
dollars from our guests for the Galapagos. And when you think
that we represent 5% of the tourism for these islands, and
you multiply this kind of an activity times 20, all of a sudden
tourism could in fact sustain places like the Charles Darwin
Research Station and the National Park and they wouldn't have
to struggle so much for funding on an annual basis.
ALAN ALDA (Narration): But there's an irony here. Tourists bring
in not only dollars -- they have also attracted thousands
of Ecuadorians to the islands to work in the tourism industry.
Together, tourists and residents pose a new threat to the
SNELL: Because there are sixteen to twenty thousand people
who live here in the Galapagos Islands, five supply ships
run out here two or three times a month each, and there are
three 727s a day that fly into the Galapagos Islands, all
that activity brings in a tremendous amount of material. Tons
and tons and tons of food and construction material come to
the Galapagos every year. Somewhere in those packages are
the introduced species of tomorrow. It's not purposeful nowadays,
but it's every bit as damaging as if it was.
ALAN ALDA (Narration): I've come to see for myself on of the
worst of these alien invaders. Charlotte Causton of the Darwin
Research Station is showing the way.
ALAN ALDA: What are all these little white things?
CAUSTON: These are the cottony cushion scale, it's an introduced
scale insect, that was introduced in 1982 into the island
of San Cristobal, and since then has spread to none other
islands in the archipelago, and attacks over forty plant species.
In the absence of its natural predators it's just gone haywire.
ALAN ALDA: How was it introduced?
CAUSTON: We're not sure. We think it was introduced in some
acacia trees that were imported into the islands, but then
again it could have been from citrus. It was definitely on
a plant and accidentally introduced. No one brought it in
ALAN ALDA (Narration): The cottony cushion scale is one of hundreds
of non-native insects that have recently sneaked into the
islands. And Charlotte is one of only two entomologists.
ALAN ALDA: If you have to go after them species by species, find
out what they do, what harm they cause, and how you can protect
against them -- and by the time you find out about one species,
you've probably got another 300 on your list, right -- how
does that make you feel?
CAUSTON: It's daunting, the prospect.
SNELL: The magnitude of the problems that face the Galapagos
Islands can seem overwhelming. And in fact they are overwhelming.
But the one thing that the people here who are motivated to
preserve biological diversity in the Galapagos Islands keep
in the forefront all the time is that this is one of the last
oceanic archipelagos in the world where we have an opportunity
to maintain a pristine environment. There are 95 to 96% of
the species that ever occurred on the Galapagos Islands that
are alive today. Some of them are in a bad state. Some of
them may go extinct before long if we're not successful at
restoration efforts for them. But the point is we have an
opportunity here. The world, actually -- it's not just Ecuador,
it's not just the Research Station, it's not just the National
Park Service -- but the world has an opportunity to preserve
biological diversity in a pristine state.
ALAN ALDA: Now, now, what about this? Why should anybody else,
who's not a scientist, care about preserving the Galapagos?
If the Galapagos disappears as a unique place, gets run over
by introduced species, so what?
ANDERSON: There's a genetic, a bank of genetic information,
and it can be squandered or it can be preserved in its current
state. The analogy is often made with a library, that you
wouldn't go into a library and wantonly destroy a whole bunch
of stuff to make shelf room to put knick-knacks on. Well,
here we've got creatures that have been coming up with solutions
to particular problems for a long, long time, and there will
be problems in the future that will need some of these solutions.
They're here. We should preserve them.
WIKELSKI: I think it's also a place of joy and insight into
natural processes and you can't really predict what people
will find here in the future. But like Darwin was inspired
by this laboratory of evolution and I think many people will
in the future. And you came because you find it interesting.
So I think it really will continue to be a lab of evolution,
where you can really see these processes happening.
ALAN ALDA (Narration): It was late one afternoon, after Lynn and
I had been out snorkeling, that the magic of the Galapagos
-- its ability as Martin said to provide joy and insight --
crystallized for me. Here we were on the equator, talking
to penguins whose ancestors came from the Antarctic. In spite
of the waves and the razor sharp rocks, we were mesmerized.
ALAN ALDA: You know, to get that close to penguins, it's an experience
I've never had before, and it's really a sensational experience.
But you're here all the time. What's it like for you?
FOWLER: As I said the other day, when you asked me why I was
still here after twenty years, it's incredible, isn't it?
Something happens different every single day. You never get
tired of these islands.
ALAN ALDA (Narration): Charles Darwin spent just five weeks in
the Galapagos, amazed as is every visitor by the tameness
of the animals and birds, and by a sense of being in a world
apart, in time and in space. But what stayed in his mind like
a slow burning fuse was the same creature or plant turning
up in different forms -- even different species -- on different
islands; a circumstance, he wrote in the Voyage of the Beagle,
"that strikes me with wonder."
ALAN ALDA: "It is the fate of most voyagers, no sooner to discover
what is most interesting in any locality, than they are hurried
from it; but I ought, perhaps, to be thankful that I obtained
sufficient materials to establish this most remarkable fact
in the distribution of organic beings. Reviewing the facts
here given, one is astonished at the amount of creative force,
if such an expression may be used, displayed on these small,
barren, and rocky islands."
ALAN ALDA (Narration): Some 20 years later he identified his
"creative force" as natural selection. And the world changed