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Blue water covers most of our planet,
but in it are set tiny specks of land,
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00:01:03,870 --> 00:01:08,590
some the tips of volcanoes,
some mere rings of coral.
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00:01:09,000 --> 00:01:11,210
They're miniature enclosed worlds
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00:01:11,420 --> 00:01:18,430
where animals and plants become transformed
into new species with extraordinary speed.
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00:01:46,080 --> 00:01:51,420
If you wanted to pick a really remote desert island
cut off from the rest of the world,
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00:01:51,630 --> 00:01:53,340
you might well choose this one.
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This is Aldabra in the Indian Ocean.
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The nearest land in that direction
is the coast of Africa, about 250 miles away.
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00:02:03,850 --> 00:02:07,100
Over there, about the same distance,
is Madagascar,
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00:02:07,350 --> 00:02:11,440
and if you sailed in that direction,
you wouldn't hit much
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00:02:11,610 --> 00:02:15,740
until you got to the coast of Australia
4,000 miles away.
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00:02:16,030 --> 00:02:20,620
The island is the tip
of an extinct submarine volcano
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00:02:20,820 --> 00:02:27,000
that rises 15,000 feet from the bottom of the
Indian Ocean and is capped with coral rock.
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00:02:27,580 --> 00:02:34,760
When it finally rose above the surface of the sea
about 50,000 years ago, it was lifeless,
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but now, a mere 50,000 years later,
well, just look.
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00:02:42,600 --> 00:02:47,310
Frigate birds, thousands of them,
circle above one end of the island.
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00:02:47,560 --> 00:02:53,770
They've come from all over the Indian Ocean,
even from India itself 2,000 miles away,
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to nest on this particular island
in the mangroves.
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00:03:05,240 --> 00:03:08,250
The white-headed birds among them
are immatures,
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00:03:08,500 --> 00:03:12,080
and there are two different species of them,
one bigger than the other.
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The males inflate their scarlet throat pouches
to show that the site is taken,
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00:03:20,630 --> 00:03:22,260
and to attract the female.
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00:03:24,930 --> 00:03:29,980
When she arrives, he persuades her to stay
with ecstatic shakes of his head.
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00:03:47,330 --> 00:03:49,250
Red-footed boobies are here, too.
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They're great travellers,
and their chicks, which are already fledging,
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may well be fishing 3,000 or 4,000 miles away
within a year.
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00:03:59,590 --> 00:04:03,510
Noddies nest not on Aldabra
but on a neighbouring atoll,
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building platforms of seaweed
in the Pisonia trees,
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00:04:07,640 --> 00:04:14,020
and beneath, on the open coral sand,
two million sooty terns lay their eggs.
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Their vast numbers are an indication
of the richness of the surrounding sea.
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Every day, the birds take from it
many tons of small fish,
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little squid and other marine creatures.
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00:04:37,000 --> 00:04:39,880
The atoll itself provides no food for them.
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All a pair of sooty terns seek from it
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are a few square inches of dry land
on which to place their single egg,
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and an absence of cats, rats
and all other egg-stealers and chick-eaters
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that plague nesting sites on the mainland.
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Such security is important to these terns,
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00:05:00,530 --> 00:05:05,110
for not only do they lay their eggs exposed
and unprotected on the ground,
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00:05:05,450 --> 00:05:08,580
but their young remain flightless
for several weeks after hatching
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00:05:08,740 --> 00:05:12,200
and a hungry cat could cause havoc among them.
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So terns find it well worthwhile,
for the sake of such security,
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to fly hundreds of miles to this island.
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The plants that grow on remote islands
like Aldabra... how do they get here?
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00:05:42,860 --> 00:05:45,320
Well, some certainly come by sea.
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00:05:45,610 --> 00:05:48,240
In a short walk along this high-water mark,
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I've picked up already
three different kinds of seeds.
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Here's the biggest floating seed of them all.
This is a coconut.
49
00:06:01,630 --> 00:06:05,170
There's the familiar nut
which contains the white flesh,
50
00:06:05,340 --> 00:06:11,760
and this husk, from which we sometimes
make coconut mats, is the flotation device.
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00:06:13,720 --> 00:06:19,560
Nuts like this can float in the sea
for up to four months. This one is dead...
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...but here is one that's alive and still sprouting
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The green stem springing from the top,
a white rootlet striking down underneath.
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00:06:31,530 --> 00:06:36,750
Under natural conditions, coconuts
establish themselves at the head of the beach.
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00:06:37,210 --> 00:06:41,460
As they grow taller, they lean out over the sand
so that when they're full-grown,
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their nuts will drop within reach of the high tide
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and be washed out to sea
to spread to other islands.
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00:06:51,300 --> 00:06:54,430
A land-living animal also reached here by sea.
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00:06:54,770 --> 00:06:58,980
The time and place to find it
is at night among the coconut groves.
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00:06:59,350 --> 00:07:04,940
It travelled here as a larva in the same way
as the coconuts, floating in the surface waters.
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00:07:05,320 --> 00:07:07,490
One or two in a million
were washed up on the beach
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00:07:07,650 --> 00:07:14,030
and crawled ashore to live on land
among the coconuts, feeding on them.
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00:07:14,790 --> 00:07:18,080
It's almost the only creature here
likely to give you a painful bite,
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00:07:18,250 --> 00:07:20,170
so it needs tackling with care.
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00:07:21,670 --> 00:07:23,460
It's the coconut crab.
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00:07:34,510 --> 00:07:38,770
Its legs are so long that it can
embrace the trunk of a coconut palm,
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00:07:38,930 --> 00:07:42,440
and it has no difficulty
in clambering up to the top.
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00:07:42,810 --> 00:07:45,730
There it cuts down young nuts with its pincers,
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00:07:45,900 --> 00:07:50,200
and returns to the ground
to feed on the soft white coconut flesh.
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00:07:50,700 --> 00:07:55,870
Crabs as a group are sea-living creatures
and breathe in water by means of gills.
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To breathe in air, the coconut crab
has developed large pouches within its shell
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00:08:00,750 --> 00:08:04,670
that have moist linings
and can act as simple lungs.
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00:08:05,290 --> 00:08:08,340
But when it breeds,
it has to return to the sea.
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00:08:08,710 --> 00:08:12,260
There it releases its eggs and sperm
into the water at high tide,
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00:08:12,430 --> 00:08:15,550
so that its larvae will circulate through the sea,
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00:08:15,850 --> 00:08:18,850
and may be washed up on some new island.
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00:08:28,650 --> 00:08:33,490
One exceptional land animal
made the voyage to Aldabra as an adult:
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00:08:33,660 --> 00:08:37,410
Its most famous inhabitant, the giant tortoise.
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00:08:38,290 --> 00:08:40,540
Most tortoises are naturally buoyant.
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00:08:40,790 --> 00:08:46,460
If one on the coast of mainland Africa, grazing
among the mangroves, were swept out to sea,
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00:08:46,670 --> 00:08:51,510
it might survive long enough to be carried
by currents to the islands of the Indian Ocean,
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and later to spread among them.
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00:08:53,680 --> 00:08:59,720
That, almost certainly, is how ancestors
of the Aldabran giant tortoise reached here.
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00:09:02,270 --> 00:09:06,520
It's not a very hospitable place
for animals like tortoises
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00:09:06,690 --> 00:09:09,190
that feed on land-living plants.
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00:09:09,820 --> 00:09:12,780
The coral rock
which forms the substance of the island
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erodes into a honeycomb
of wickedly sharp blades and spikes.
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00:09:18,530 --> 00:09:24,500
Any creature moving over it has to step with care
if it's not to cut itself badly.
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00:09:38,050 --> 00:09:43,430
Here and there, the rock forms deep pits
into which tortoises sometimes tumble.
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00:09:43,810 --> 00:09:46,350
When that happens, there is no escape,
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00:09:46,520 --> 00:09:52,030
and the trapped animals,
even if they survive the fall, die from starvation
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00:09:54,610 --> 00:10:00,370
Quite apart from such traps, the island
is a harsh, taxing place in which to live.
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00:10:00,950 --> 00:10:06,920
The tropical sun, beating down on the animals,
threatens to bake them alive inside their shells,
94
00:10:07,080 --> 00:10:09,500
and the remains of casualties are common.
95
00:10:14,510 --> 00:10:16,220
So as the day heats up,
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the tortoises head determinedly
for the few trees that can provide shade.
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00:10:23,520 --> 00:10:29,480
Here and there on some beaches
grow low, windswept Guettarda trees.
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00:10:30,520 --> 00:10:35,150
By noon, the ground beneath their branches
is packed with refugees from the sun,
99
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waiting for the temperature to fall
so that they can search for edible leaves.
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00:10:45,080 --> 00:10:47,370
Birds, too, can overheat.
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00:10:48,620 --> 00:10:53,500
The frigates swoop over the one almost
permanent lagoon of rainwater on the island,
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snatching sips from its surface.
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00:11:24,910 --> 00:11:27,450
Tortoises, too, must have fresh water.
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00:11:27,790 --> 00:11:29,410
Although they don't drink every day,
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00:11:29,620 --> 00:11:33,000
they must do every week or so
if they're to survive.
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00:11:51,350 --> 00:11:54,820
Water can also cool an overheated body.
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00:11:59,900 --> 00:12:01,570
As the dry season progresses,
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00:12:01,780 --> 00:12:06,700
the water evaporates and the pools
get smaller and more crowded.
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00:12:42,150 --> 00:12:46,660
Many that came here for relief
are near the end of their strength.
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00:12:46,910 --> 00:12:52,540
Some are unable to drag themselves
out of the mud, and so die of starvation.
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00:13:05,340 --> 00:13:10,720
And yet, in spite of all these hardships,
the tortoises breed and proliferate.
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There are some 150,000 of them on the atoll.
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Their staple food is vegetation and
they crop the grass right down to the rootstock.
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00:13:26,410 --> 00:13:29,200
But as island animals everywhere tend to do,
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00:13:29,450 --> 00:13:34,670
they've broadened their taste in food
to include almost anything that is edible,
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including the carcasses
of their dead companions.
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Flesh is too nutritious
to be allowed to rot and go to waste
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in this land where there is so little to eat.
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00:14:07,490 --> 00:14:12,620
50,000 years, which is the time, apparently,
that Aldabra has been above the sea,
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00:14:12,910 --> 00:14:16,000
is not a very long time in terms of evolution.
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00:14:16,290 --> 00:14:19,960
Nonetheless, 50,000 years of isolation
on the island
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00:14:20,130 --> 00:14:24,510
has brought changes
to many plants and animals that live here.
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00:14:24,800 --> 00:14:27,630
They've begun to take on their own character,
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00:14:27,890 --> 00:14:33,430
so now they differ slightly both
from the ancestors which colonised the island
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00:14:33,640 --> 00:14:37,230
and from their nearest relations
elsewhere in the world.
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For example, this close-cropped withered turf
around me
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contains about 20 different species of plants.
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All have been relentlessly cropped
by giant tortoises like that.
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00:14:51,740 --> 00:14:56,500
And look, for example, at this little sedge.
130
00:14:57,540 --> 00:15:04,000
Most sedges bear their flowers at the top
of stems that rise quite high above the leaves.
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Flowers sticking up like this would not survive
long on Aldabra. The tortoises would eat them.
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These Aldabran sedges bear their flowers
and develop their seeds
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close to the rootstock where the jaws
of the hungry tortoises can't reach them.
134
00:15:22,480 --> 00:15:27,820
The changes that take place in an island species
are not always directly useful like that.
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00:15:28,200 --> 00:15:31,320
Another of Aldabra's plants has changed in a way
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that seems to have
no practical significance at all.
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00:15:35,200 --> 00:15:38,000
This is a lily called Lomatophyllum.
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00:15:38,290 --> 00:15:44,550
It's slightly different in colour from Lomatophyll
growing elsewhere, but that's all.
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The difference is very trivial.
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But some island plants are spectacularly
different from their nearest relatives.
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Very, very rarely,
extraordinary double nuts like this
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are washed up on the shores
of the coral islands of the Indian Ocean.
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For centuries,
nobody knew where they came from.
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00:16:07,780 --> 00:16:11,860
Some said they were produced
by fantastic palm trees
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00:16:12,070 --> 00:16:17,080
that grew under the surface of the sea,
so they were called coco-de-mer.
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00:16:17,330 --> 00:16:22,330
People believed that their kernels
could be made into irresistible love potions
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and that their shells, when turned into a cup,
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would render the most powerful poison harmless.
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00:16:29,970 --> 00:16:34,090
A single nut like this
was literally worth a king's ransom.
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00:16:34,340 --> 00:16:36,680
It wasn't until the 18th century
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00:16:36,850 --> 00:16:40,560
that people discovered
that the palms that produced these nuts
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grew in one tiny group of islands
in the Seychelles, some 700 miles from Aldabra.
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00:16:49,320 --> 00:16:55,030
The largest surviving group of these trees
stands on the little island of Praslin.
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00:17:29,110 --> 00:17:31,740
There are male and female trees.
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00:17:32,490 --> 00:17:36,370
The males produce small yellow flowers
on long spikes,
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and on them lives a little gecko,
feeding on their nectar and pollen.
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00:17:42,250 --> 00:17:44,580
Once again, it's an island original,
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00:17:44,830 --> 00:17:49,210
slightly different in colour
from others in neighbouring islands.
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00:17:51,130 --> 00:17:55,840
The female flowers start as small reddish buds,
no bigger than a man's fist,
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00:17:56,140 --> 00:18:01,350
but they will develop into the biggest seed
produced by any plant.
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It takes seven years for the nuts to develop,
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and when they are mature,
they are so large and so heavy
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that almost the only way of opening them
is with a saw.
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00:18:21,030 --> 00:18:25,660
Inside, you can see how very different
they are from coconuts.
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Not only do they have two lobes to them,
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00:18:29,290 --> 00:18:33,800
but the nut itself is full solid with flesh.
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Flesh that is so heavy
that these mature nuts won't float in sea water.
168
00:18:39,180 --> 00:18:41,010
Indeed, sea water kills them.
169
00:18:42,180 --> 00:18:44,600
And that means two things.
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First of all, that these palms have never
been able to spread to other islands,
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and secondly,
that they must have actually evolved here.
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Isolation changes not only plants but animals.
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00:18:59,990 --> 00:19:06,160
On Aldabra, wandering among the tortoises
are sacred ibis with light blue eyes.
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00:19:06,410 --> 00:19:08,580
Others elsewhere have dark eyes.
175
00:19:08,830 --> 00:19:14,800
The Aldabran ibis breed among themselves
and feed on small shore creatures.
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00:19:15,210 --> 00:19:17,590
Land crabs are far too big to be eaten,
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00:19:17,760 --> 00:19:20,970
but they have to be pecked
to clear them out of the way.
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00:19:25,350 --> 00:19:30,690
Several species of Aldabran birds have developed
slight variations that make them unique.
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00:19:30,900 --> 00:19:36,570
The kestrel here is slightly smaller than the
Madagascar species, but otherwise the same.
180
00:19:36,780 --> 00:19:41,780
The Aldabran sunbird, however,
is a little darker than its African relations.
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00:19:51,880 --> 00:19:56,090
But perhaps the most dramatic
and certainly the most endearing quality
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00:19:56,260 --> 00:20:01,220
brought to some of the birds of Aldabra
by isolation is this.
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00:20:03,300 --> 00:20:07,020
Not only extreme tameness, but flightlessness.
184
00:20:07,270 --> 00:20:09,480
This is the Aldabran rail.
185
00:20:09,850 --> 00:20:12,020
Flying takes a lot of energy.
186
00:20:12,270 --> 00:20:16,320
It's of obvious value
when escaping ground-living enemies,
187
00:20:16,480 --> 00:20:20,610
but there are no such enemies
on Aldabra or other remote islands.
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00:20:20,900 --> 00:20:25,700
So some birds that reach such islands by air
have given up flying.
189
00:20:25,950 --> 00:20:30,540
Their wing muscles have dwindled
and they can't fly even if they wanted to.
190
00:20:30,830 --> 00:20:33,000
The Aldabran rail is only one example.
191
00:20:34,840 --> 00:20:39,840
A kind of pigeon once lived on another island
in the Indian Ocean: Mauritius.
192
00:20:40,220 --> 00:20:43,930
It, too, became flightless
and grew as big as a turkey.
193
00:20:44,390 --> 00:20:50,230
It was so tame that European sailors
were able to kill it with clubs.
194
00:20:50,600 --> 00:20:54,690
They called it the dodo,
and in less than 200 years after finding it,
195
00:20:54,860 --> 00:20:56,900
they'd exterminated it.
196
00:20:58,780 --> 00:21:00,900
Grazing alongside the dodo in Mauritius,
197
00:21:01,070 --> 00:21:06,160
and living in other islands in the Indian Ocean
as well, were giant tortoises.
198
00:21:06,450 --> 00:21:11,910
They, too, were taken for food by seamen
and were exterminated.
199
00:21:12,290 --> 00:21:16,130
But Aldabra is so remote
that few ships come near it,
200
00:21:16,290 --> 00:21:19,460
and here alone, the tortoises have survived.
201
00:21:21,970 --> 00:21:27,430
It seems likely that the African ancestors
of these creatures were of a normal size,
202
00:21:27,600 --> 00:21:32,270
and that these tortoises became giants
as a consequence of living on islands.
203
00:21:35,480 --> 00:21:39,570
Isolation may have had another effect
on the tortoises as well.
204
00:21:39,940 --> 00:21:42,190
When African tortoises are threatened,
205
00:21:42,360 --> 00:21:46,870
they behave in the same way
as this baby Aldabran tortoise.
206
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They first pull in their head,
207
00:21:49,450 --> 00:21:53,290
and then they pull after it
their heavily armoured front legs
208
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so that nothing sticks out and they're
comparatively safe from their enemies.
209
00:21:59,710 --> 00:22:04,050
But when the Aldabran tortoise grows up,
its proportions change,
210
00:22:04,260 --> 00:22:05,800
as this one's have done.
211
00:22:06,010 --> 00:22:12,060
This one is now so big
that these huge legs won't fit into this space,
212
00:22:12,270 --> 00:22:15,690
so that whatever it does, something sticks out.
213
00:22:15,850 --> 00:22:20,190
It's a fair bet
that if there was a hyena on the island,
214
00:22:20,360 --> 00:22:23,030
it would make a meal of the giant tortoise.
215
00:22:23,490 --> 00:22:27,030
But there isn't on Aldabra, so this creature's safe.
216
00:22:29,490 --> 00:22:32,870
Just why the island tortoises
should have grown so huge,
217
00:22:33,080 --> 00:22:36,920
and another species has done the same
in the Galapagos islands,
218
00:22:37,080 --> 00:22:38,920
is by no means clear.
219
00:22:40,000 --> 00:22:42,840
It may be that a large animal
with big reserves of fat
220
00:22:43,010 --> 00:22:47,220
is better able to survive bad seasons
when there's little to eat.
221
00:22:47,550 --> 00:22:50,760
It may even be
that with no predators on the island,
222
00:22:50,930 --> 00:22:53,560
these long-lived creatures just go on growing,
223
00:22:53,720 --> 00:22:57,440
but it is not a phenomenon
that is restricted to tortoises.
224
00:22:57,690 --> 00:23:03,940
On an island 3,000 miles away from Aldabra,
there is another giant reptile.
225
00:23:06,610 --> 00:23:09,570
Komodo is a small island in Indonesia.
226
00:23:09,950 --> 00:23:12,030
From here, back in the 1920s,
227
00:23:12,200 --> 00:23:16,960
came stories of a huge lizard
that became known as the Komodo dragon,
228
00:23:17,120 --> 00:23:20,000
and here the dragons still live.
229
00:23:44,820 --> 00:23:46,360
It's not difficult to find them.
230
00:23:46,530 --> 00:23:50,860
All you need is the carcass of a goat,
preferably decayed and smelly,
231
00:23:51,030 --> 00:23:54,030
and the scent will attract them from miles around.
232
00:24:26,360 --> 00:24:31,780
It used to be thought that
these very big ones were entirely scavengers,
233
00:24:31,990 --> 00:24:35,030
relying on what carrion they could find,
234
00:24:35,330 --> 00:24:40,540
but now we know that
actually they are active killers.
235
00:24:40,870 --> 00:24:50,220
They attack and kill goats,
young buffalo, and even on occasion, man.
236
00:24:50,920 --> 00:24:54,430
The reason that I can stand here
with relative safety
237
00:24:54,600 --> 00:24:59,890
is that their eyesight is not very good,
they are almost deaf,
238
00:25:00,100 --> 00:25:03,520
and they rely on their senses,
239
00:25:03,730 --> 00:25:08,820
primarily on that big yellow tongue
which flicks out and tastes the air.
240
00:25:11,070 --> 00:25:16,990
So with any luck, the smell of these dead goats
is more powerful than mine,
241
00:25:17,160 --> 00:25:18,790
so they will take no notice of me.
242
00:25:20,290 --> 00:25:25,040
They are, in fact, the kings of their island.
They are the top predator.
243
00:25:25,460 --> 00:25:29,090
There is nothing here
which preys upon them and is bigger,
244
00:25:30,920 --> 00:25:33,680
and nothing with which
they have to share their food.
245
00:25:35,260 --> 00:25:40,430
So, from that point of view,
there is no reason why they shouldn't grow big.
246
00:25:41,480 --> 00:25:45,150
And the fact is that there is
a positive advantage in growing big,
247
00:25:45,310 --> 00:25:51,400
because the big ones
are getting the bigger share of the food.
248
00:25:52,990 --> 00:25:58,450
Not only that, but we now know
that these big ones eat small ones.
249
00:25:59,410 --> 00:26:05,540
That perhaps is a reason why,
in the isolation of their island,
250
00:26:05,790 --> 00:26:09,460
these kings of Komodo have grown so huge.
251
00:26:11,050 --> 00:26:13,510
And they are indeed immense.
252
00:26:14,010 --> 00:26:19,140
They're related to the water monitors
of Asia and Africa and the goannas of Australia,
253
00:26:19,430 --> 00:26:21,010
but they are much more massive,
254
00:26:21,180 --> 00:26:26,940
for whereas two-thirds of the length of these
other monitors is taken up by a long thin tail,
255
00:26:27,190 --> 00:26:30,230
the dragon's tail is only about half its length.
256
00:26:30,980 --> 00:26:37,740
Big ones like this can weigh up to 100 pounds
and grow to over nine feet long.
257
00:26:44,710 --> 00:26:46,460
Komodo is not, like Aldabra,
258
00:26:46,620 --> 00:26:50,090
a coral atoll growing
on the drowned tip of a submarine volcano,
259
00:26:50,290 --> 00:26:55,470
but the eroded remains of one that stood
many thousands of feet above sea level.
260
00:26:57,010 --> 00:27:00,800
Volcanoes, indeed,
have built many of the most isolated islands.
261
00:27:01,050 --> 00:27:04,810
The Hawaiian islands,
lying in the eastern Pacific, are all volcanic,
262
00:27:04,980 --> 00:27:08,520
and the biggest and newest of them
is still erupting.
263
00:27:38,800 --> 00:27:44,140
Torrents of basaltic lava erupting from vents
10,000 feet up on the mountain
264
00:27:44,310 --> 00:27:47,980
sometimes flow for many miles
down the volcano's flanks.
265
00:28:06,700 --> 00:28:09,080
When, eventually, they cool and solidify,
266
00:28:09,250 --> 00:28:13,210
they become vast slopes of black naked rock.
267
00:28:16,000 --> 00:28:21,090
Such areas as this
may remain virtually sterile for decades.
268
00:28:24,260 --> 00:28:30,850
Some vents produce vast quantities of granular
ash which builds up around them into cones.
269
00:28:31,730 --> 00:28:34,690
Plants have a better chance
of getting root on such material,
270
00:28:34,980 --> 00:28:39,570
and within a century or so,
the ash slopes may be covered with green.
271
00:28:41,030 --> 00:28:44,450
These high islands
collect moisture-laden clouds,
272
00:28:44,620 --> 00:28:48,580
and on the windward side,
rain falls very heavily indeed.
273
00:28:49,580 --> 00:28:51,920
Streams flowing down the mountainside
274
00:28:52,080 --> 00:28:57,170
cut through the layers
of loosely compacted ash, eroding deep valleys.
275
00:28:57,340 --> 00:28:59,510
So, unlike a coral atoll,
276
00:28:59,720 --> 00:29:03,720
which is a plain platform
of coral, sand and rock only a few feet high,
277
00:29:03,890 --> 00:29:06,760
these immense volcanic islands of Hawaii
278
00:29:06,930 --> 00:29:10,310
offered their colonists a great variety of habitat
279
00:29:10,480 --> 00:29:13,150
from high cold slopes of ash on the summits
280
00:29:13,350 --> 00:29:18,230
to well-watered valleys, hot, lush and humid,
near sea level,
281
00:29:18,820 --> 00:29:24,160
from new, naked basalt to long-established
forest growing on ancient lava flows.
282
00:29:24,450 --> 00:29:32,160
To exploit them, the animal colonists changed
not into just one new form, but into a multitude.
283
00:29:35,000 --> 00:29:36,460
This bird, the palila,
284
00:29:36,670 --> 00:29:40,960
is one of a large family of closely related
Hawaiian birds, the honeycreepers.
285
00:29:41,380 --> 00:29:45,550
Their ancestors were probably
finch-like birds that were swept here,
286
00:29:45,840 --> 00:29:49,180
perhaps by a freak storm
many thousands of years ago.
287
00:29:49,430 --> 00:29:52,890
Once here,
they developed into over 30 different species,
288
00:29:53,060 --> 00:29:55,350
each with its own diet and habitat.
289
00:29:55,850 --> 00:29:57,900
The palila lives largely on seeds
290
00:29:58,070 --> 00:30:02,650
and has the short, powerful beak
needed to open and crack them.
291
00:30:08,120 --> 00:30:14,160
The 'amakihi, while there's no doubt
that it and the palila are related,
292
00:30:14,370 --> 00:30:17,920
has a slender beak,
suited to picking up small insects
293
00:30:18,090 --> 00:30:20,590
and sipping nectar from shallow flowers.
294
00:30:21,090 --> 00:30:25,220
Some species have developed
striking feather colours and adornments.
295
00:30:25,470 --> 00:30:28,470
These enable the male and female
to identify one another
296
00:30:28,640 --> 00:30:31,640
so they don't interbreed with near cousins,
297
00:30:31,850 --> 00:30:34,390
and the species becomes increasingly distinct.
298
00:30:35,690 --> 00:30:41,480
So the 'apapane not only has a longer beak
to suit its almost exclusive diet of nectar,
299
00:30:41,690 --> 00:30:43,690
but a conspicuous red head.
300
00:30:45,610 --> 00:30:49,740
The 'akohekohe
lives on a mixed diet of insects and nectar,
301
00:30:49,910 --> 00:30:53,870
and has developed a little crest of white feathers
at the base of its beak.
302
00:30:58,420 --> 00:31:02,880
The 'i'iwi is scarlet
and has a particularly long curved bill
303
00:31:03,090 --> 00:31:06,800
that allows it to probe deep
into trumpet-shaped flowers
304
00:31:06,970 --> 00:31:09,850
such as giant lobelias and bananas.
305
00:31:20,650 --> 00:31:25,030
And perhaps most engaging of all,
the akiapolaau,
306
00:31:25,190 --> 00:31:27,780
with a splendid dual-purpose beak,
307
00:31:27,990 --> 00:31:32,080
the lower mandible pick-like
to chip away bark to find insects,
308
00:31:32,240 --> 00:31:37,160
and an upper mandible elongated into a probe
with which to winkle them out.
309
00:31:41,290 --> 00:31:45,010
It's located a beetle larva
burrowing away within the bark.
310
00:31:45,300 --> 00:31:50,680
Look how dexterously it uses the two halves
of its beak for these different purposes.
311
00:32:04,900 --> 00:32:09,820
The situation amongst Hawaii's insects
is even more extreme than it is among its birds.
312
00:32:10,200 --> 00:32:15,080
There is a kind of fly called Drosophila.
It's found in many parts of the world.
313
00:32:15,240 --> 00:32:19,120
In North America, for example,
there are about 200 species,
314
00:32:19,290 --> 00:32:25,340
but in these tiny islands of Hawaii,
there are at least 800.
315
00:32:26,300 --> 00:32:30,010
It seems that soon after the islands' formation,
316
00:32:30,180 --> 00:32:35,140
one or at most two species of Drosophila
reached the islands,
317
00:32:35,310 --> 00:32:40,100
and they found the same situation as
the honeycreepers found, a lot of vacant niches.
318
00:32:40,350 --> 00:32:44,860
And so they evolved to fill them,
and they are now Drosophila,
319
00:32:45,070 --> 00:32:50,990
the larvae of which
feed on fruit or rotting leaves or fungi,
320
00:32:51,160 --> 00:32:53,950
or bark or even spiders' eggs.
321
00:32:54,320 --> 00:33:00,370
But now the situation becomes more complex
because in Hawaii, there are lava flows like this,
322
00:33:00,960 --> 00:33:06,960
and such lava flows often isolate
patches of ancient forest like that over there,
323
00:33:07,170 --> 00:33:09,420
and in one small patch of forest,
324
00:33:09,670 --> 00:33:16,220
there may well be one particular species
of Drosophila that occurs nowhere else.
325
00:33:40,580 --> 00:33:43,370
And there are some just there.
326
00:33:53,470 --> 00:33:58,260
These particular ones belong to a group
which have evolved, in their isolation,
327
00:33:58,470 --> 00:34:00,520
an extraordinary courtship behaviour,
328
00:34:00,680 --> 00:34:03,980
just as some honeycreepers
have evolved bright colours.
329
00:34:04,560 --> 00:34:07,690
It's an insect equivalent
of the arena display of antelope.
330
00:34:07,900 --> 00:34:13,820
The males maintain tiny territories
and display and battle with one another.
331
00:34:14,400 --> 00:34:18,530
Instead of antlers,
they've developed heads shaped like mallets.
332
00:34:27,750 --> 00:34:31,920
In another species, the male courts the female
by hoisting his abdomen over his back
333
00:34:32,090 --> 00:34:35,220
and showering her with an aphrodisiac perfume.
334
00:34:38,220 --> 00:34:41,850
Isolation has also affected the wings
of Hawaiian insects.
335
00:34:42,060 --> 00:34:44,140
Flying on an island is dangerous.
336
00:34:44,390 --> 00:34:46,730
It risks being blown out to sea,
337
00:34:48,400 --> 00:34:51,650
and this extraordinary bug
never takes to the air.
338
00:34:52,150 --> 00:34:56,240
Its wings are tiny,
and used only for flirting in courtship.
339
00:34:59,740 --> 00:35:01,990
This lacewing can't even use them for that.
340
00:35:02,240 --> 00:35:05,330
Its wings have become fused together
to form a shell.
341
00:35:06,170 --> 00:35:10,000
The Hawaiian cranefly
has lost its wings completely.
342
00:35:10,670 --> 00:35:13,670
This cranefly's taste for fruit
is typical of its family,
343
00:35:13,840 --> 00:35:16,970
but other insects
have changed their feeding habits.
344
00:35:17,300 --> 00:35:21,100
This flightless bug has adopted
the hunting techniques of the mantis
345
00:35:21,310 --> 00:35:23,470
which never naturally reached the island.
346
00:35:26,810 --> 00:35:29,230
And this fly is going to get a shock.
347
00:35:32,270 --> 00:35:35,610
The twig caterpillar doesn't,
like most twig caterpillars elsewhere,
348
00:35:35,820 --> 00:35:38,530
feed on leaves, but has become a carnivore.
349
00:35:50,290 --> 00:35:53,880
It detected the fly with tiny hairs on its back en
350
00:35:54,130 --> 00:35:58,720
They trigger the caterpillar to arch backwards
and pounce on whatever touched it.
351
00:36:03,100 --> 00:36:07,770
So isolation, by restricting the kinds of creature
that reached Hawaii,
352
00:36:07,940 --> 00:36:14,070
allows those that did great freedom
to develop into different and unexpected forms.
353
00:36:17,320 --> 00:36:22,570
Human beings, the Polynesians,
reached Hawaii several thousand years ago.
354
00:36:22,950 --> 00:36:25,740
When Europeans arrived,
they found to their surprise
355
00:36:25,950 --> 00:36:29,750
an unknown people
with an elaborate and splendid culture.
356
00:36:30,370 --> 00:36:32,330
The Hawaiians were superb seamen.
357
00:36:32,670 --> 00:36:34,800
They not only paddled dugout canoes,
358
00:36:35,000 --> 00:36:40,380
but sailed immense ocean-going double canoes
that could carry several hundred passengers,
359
00:36:40,680 --> 00:36:44,850
and that tradition survives still
in many parts of the Pacific.
360
00:36:56,690 --> 00:37:02,530
The last of the really big canoes
must have disappeared about 100 years ago,
361
00:37:02,780 --> 00:37:05,580
but still, in the remoter parts of the Pacific,
362
00:37:05,830 --> 00:37:09,710
people remembered the techniques
that were used to sail them,
363
00:37:09,870 --> 00:37:13,540
and still practise the skills needed to build them
364
00:37:13,880 --> 00:37:17,880
This particular canoe,
which is very big for modern times,
365
00:37:18,090 --> 00:37:24,300
was built on the tiny island of Ribono in Kiribati
the islands that used to be called the Gilberts.
366
00:37:24,640 --> 00:37:30,980
It is only about 50 feet long, enormous for today,
but only half the size of the old canoes,
367
00:37:31,140 --> 00:37:37,480
and still the people are prepared to sail
on journeys of up to 1,000 miles in it.
368
00:37:37,730 --> 00:37:43,780
The techniques for building it
are those that were used for the old canoes.
369
00:37:44,030 --> 00:37:45,990
The lashings, for instance.
370
00:37:46,200 --> 00:37:49,240
They are made from the fibres of coconut husks.
371
00:37:49,830 --> 00:37:52,660
Clumps are teased out, rolled and twisted
372
00:37:52,830 --> 00:37:55,460
so that each fibre binds with its neighbours.
373
00:37:55,750 --> 00:38:00,130
It is a repetitious job, but a skilled one
if the string is going to be strong,
374
00:38:00,340 --> 00:38:03,380
and it is taken on
by the women and the old people.
375
00:38:03,630 --> 00:38:07,680
Hundreds of yards will be needed
to build a big canoe.
376
00:38:14,650 --> 00:38:17,730
It's used not only for lashing one spar to another
377
00:38:17,900 --> 00:38:22,780
but for sewing together the planks
that form the sides of the big canoes.
378
00:38:49,720 --> 00:38:54,730
The Pandanus tree produces strap-like leaves,
which, when dried and split,
379
00:38:54,940 --> 00:39:00,730
provide ribbons that are woven
into strong and durable mats to serve as sails.
380
00:39:10,450 --> 00:39:13,080
So if you have the necessary
knowledge and skill,
381
00:39:13,250 --> 00:39:19,460
even a small atoll can provide
all the materials to build an ocean-going canoe.
382
00:39:20,420 --> 00:39:24,010
In such craft, the Polynesians
travelled right across the Pacific.
383
00:39:24,510 --> 00:39:28,470
For a long time, Europeans,
so proud of their navigating skills,
384
00:39:28,640 --> 00:39:31,760
maintained that the Polynesian voyages
were accidental,
385
00:39:31,930 --> 00:39:34,390
made when fishing canoes were blown off course.
386
00:39:35,020 --> 00:39:41,480
But the huge canoes carried women and children,
and were loaded with plants and animals,
387
00:39:41,650 --> 00:39:45,030
with every intention of founding new colonies.
388
00:39:46,570 --> 00:39:51,450
The Polynesian navigators had and have
the most astonishing powers of observation
389
00:39:51,620 --> 00:39:53,290
by which they find their way.
390
00:39:54,370 --> 00:39:57,210
A particular kind of bird
during one season of the year
391
00:39:57,370 --> 00:40:00,080
will always travel in a certain direction.
392
00:40:00,710 --> 00:40:05,590
Some birds are ocean-goers, others
seldom travel far from their nesting grounds,
393
00:40:05,800 --> 00:40:10,390
so spotting one
can indicate that there's land close by,
394
00:40:10,550 --> 00:40:12,970
and following it may take you there.
395
00:40:16,310 --> 00:40:17,980
Distant islands can be detected
396
00:40:18,190 --> 00:40:21,770
by their effect on the ripples
on the surface of the sea.
397
00:40:22,860 --> 00:40:25,730
Tall islands trail clouds of characteristic shape
398
00:40:25,940 --> 00:40:28,490
like smoke from a chimney blown by the wind,
399
00:40:28,650 --> 00:40:30,700
and since they are so high in the sky,
400
00:40:30,860 --> 00:40:35,620
they can be recognised and identified
long before the island is visible.
401
00:40:37,080 --> 00:40:42,130
Using such techniques and observing
the sun and stars, the pattern of the winds,
402
00:40:42,330 --> 00:40:45,670
and feeling through the rudder
the movements of swells and currents,
403
00:40:45,880 --> 00:40:49,010
the Polynesians colonised island after island.
404
00:40:49,380 --> 00:40:51,760
Their original home was in the western Pacific.
405
00:40:51,930 --> 00:40:57,310
They reached the Tahitian islands,
in the centre of the ocean, over 2,000 years ago.
406
00:41:00,440 --> 00:41:04,570
They sailed so far eastward
that they reached Easter Island,
407
00:41:04,770 --> 00:41:07,610
three-quarters of the way
to the coast of South America.
408
00:41:09,360 --> 00:41:12,610
Those that settled here
seem to have been more isolated than most,
409
00:41:12,780 --> 00:41:17,830
and, like so many other islanders,
they developed their own culture.
410
00:41:18,290 --> 00:41:21,620
They carved the rocks
of their headlands into strange shapes.
411
00:41:22,210 --> 00:41:24,960
On the flanks of the great volcano
that built their island,
412
00:41:25,170 --> 00:41:31,220
they set up huge images whose enigmatic faces
have haunted the European imagination
413
00:41:31,430 --> 00:41:35,680
ever since they were discovered
by westerners two centuries ago.
414
00:41:48,230 --> 00:41:50,490
The heyday of the Easter Island culture
415
00:41:50,650 --> 00:41:54,240
seems to have been passed
long before Europeans arrived,
416
00:41:54,570 --> 00:42:00,790
for many statues were overturned
and some lay half-finished and abandoned
417
00:42:00,950 --> 00:42:03,620
where they had been carved in the quarries.
418
00:42:14,470 --> 00:42:18,430
The scale of these Polynesian voyages
is difficult to imagine.
419
00:42:18,640 --> 00:42:24,480
From their headquarters in Samoa
to their most northerly colony in Hawaii,
420
00:42:24,650 --> 00:42:29,110
which they reached by way of the Marquesas,
was some 5,000 miles.
421
00:42:30,030 --> 00:42:34,280
The journey to Easter Island, about 3,300 miles.
422
00:42:34,740 --> 00:42:36,740
But the most extraordinary voyage of all
423
00:42:36,910 --> 00:42:42,580
took them across 4,000 miles of open ocean,
south to New Zealand.
424
00:42:44,210 --> 00:42:47,630
The group that landed here,
ancestors of the Maori,
425
00:42:47,790 --> 00:42:51,210
arrived about 1,500 years ago.
426
00:42:52,210 --> 00:42:55,550
The land they discovered
must have been a great surprise to them,
427
00:42:55,760 --> 00:43:00,010
for it was very different from the tropical island
from which they had come.
428
00:43:00,850 --> 00:43:03,680
For much of the year, it was bitterly cold.
429
00:43:04,730 --> 00:43:09,400
In the South Island stood great mountain ranges
covered with snow and ice
430
00:43:09,610 --> 00:43:12,360
that the Maori can never have seen before.
431
00:43:14,030 --> 00:43:19,200
Not only that, but the forests
were far richer in animals and plants
432
00:43:19,410 --> 00:43:21,790
than any island they had yet discovered.
433
00:43:22,240 --> 00:43:26,620
That was because these islands
had a very different origin and history.
434
00:43:27,830 --> 00:43:32,170
They were neither flat coral atolls
nor were they the tips of volcanoes
435
00:43:32,340 --> 00:43:37,590
that had risen above the surface of the Pacific
in comparatively recent geological time.
436
00:43:38,510 --> 00:43:41,180
These islands of New Zealand
were ancient lands.
437
00:43:41,350 --> 00:43:43,430
Fragments of a great supercontinent
438
00:43:43,600 --> 00:43:48,150
of which Australia, Antarctica
and South America had been a part.
439
00:43:48,480 --> 00:43:53,530
In consequence, they had on them
many more different kinds of animals
440
00:43:53,690 --> 00:43:55,570
than other more recent islands.
441
00:43:55,860 --> 00:43:58,820
They had animals like this.
442
00:44:00,410 --> 00:44:02,660
This is the tuatara.
443
00:44:03,080 --> 00:44:09,040
It's a reptile, it's nocturnal and solitary,
and it's a flesh-eater.
444
00:44:09,420 --> 00:44:15,340
It feeds on insects, earthworms
and even young nestling birds.
445
00:44:16,090 --> 00:44:20,970
It might look like a lizard,
but it's a more ancient creature than that,
446
00:44:21,180 --> 00:44:23,640
more closely related to the early dinosaurs
447
00:44:23,810 --> 00:44:26,230
than it is to the modern family of lizards.
448
00:44:26,600 --> 00:44:31,100
Once creatures like it must have swarmed
over that great supercontinent,
449
00:44:31,270 --> 00:44:34,820
but New Zealand split away
from the supercontinent
450
00:44:35,030 --> 00:44:37,150
before the great expansion of the early mammals
451
00:44:37,320 --> 00:44:41,700
which ultimately led to the extinction
of most of the early reptiles.
452
00:44:41,950 --> 00:44:47,120
Only in New Zealand
did the tuatara remain safe.
453
00:44:47,870 --> 00:44:52,840
And New Zealand also has been
a sanctuary for another early creature.
454
00:44:55,090 --> 00:44:58,670
The kiwi. It's a bird, but what an odd one.
455
00:44:59,010 --> 00:45:03,470
It has no visible wings and no tail
and lives in a burrow.
456
00:45:08,270 --> 00:45:12,480
There, it produces a single and enormous egg.
457
00:45:20,150 --> 00:45:22,110
Flightless, living in burrows,
458
00:45:22,280 --> 00:45:26,410
with feathers so long and loose
they look like shaggy fur,
459
00:45:26,620 --> 00:45:31,000
and running quietly across the forest floor
at night in search of food,
460
00:45:31,210 --> 00:45:35,960
this odd animal could be considered
a kind of bird equivalent of a mammal.
461
00:45:36,420 --> 00:45:40,090
Indeed, the kiwi does play that role
in these islands
462
00:45:40,380 --> 00:45:44,180
where originally there were
no land mammals of any kind.
463
00:45:53,520 --> 00:45:57,820
It has, however, retained that characteristic
possession of the bird, a beak...
464
00:45:59,990 --> 00:46:01,700
...and it uses it to collect worms,
465
00:46:01,860 --> 00:46:06,740
plunging it deep into the earth
to smell for them as a mammal does.
466
00:46:10,700 --> 00:46:15,210
The ancestors of the kiwi were flightless
before New Zealand was isolated,
467
00:46:15,380 --> 00:46:17,380
for the kiwi is a ratite.
468
00:46:18,550 --> 00:46:22,050
Other members of that family
of ancient flightless birds
469
00:46:22,220 --> 00:46:25,680
still survive on other fragments
of the great supercontinent.
470
00:46:25,840 --> 00:46:31,390
There's the ostrich in Africa, the rhea
in South America and the emu in Australia.
471
00:46:31,730 --> 00:46:34,230
All those are bigger than the kiwi,
472
00:46:34,390 --> 00:46:38,070
but the kiwi once had a cousin
living here in New Zealand
473
00:46:38,230 --> 00:46:40,230
that was bigger than the lot of them.
474
00:46:40,480 --> 00:46:45,860
It was probably the tallest bird
that has ever existed, the moa.
475
00:46:47,570 --> 00:46:51,250
Its bones have been found
in great numbers here in New Zealand.
476
00:46:51,410 --> 00:46:57,420
Often in between the ribs
have been found piles of polished pebbles.
477
00:46:57,630 --> 00:47:03,720
They were the stones from the gizzard
with which the moa ground up its food,
478
00:47:03,880 --> 00:47:11,270
and from the vegetable remains, we know
that it ate fruit, twigs and the leaves of trees.
479
00:47:13,350 --> 00:47:17,770
There were a dozen or so
different species of moa of varying sizes.
480
00:47:19,480 --> 00:47:21,980
This particular one was the biggest of all.
481
00:47:22,280 --> 00:47:25,360
It was not the heaviest bird
that has ever lived,
482
00:47:25,570 --> 00:47:29,780
its relative, the extinct elephant bird
that lived in Madagascar was that,
483
00:47:29,990 --> 00:47:35,040
but its weight nonetheless
was substantial, about 520 pounds,
484
00:47:35,250 --> 00:47:40,840
and it was the tallest of all birds,
standing over 13 feet high.
485
00:47:41,380 --> 00:47:44,510
In fact, it was the bird equivalent
of a giraffe.
486
00:47:47,180 --> 00:47:52,810
This is the mummified head and neck
of one of the smaller species of moa,
487
00:47:53,060 --> 00:47:57,770
and it suggests, because many necks
have been found attached to heads,
488
00:47:58,020 --> 00:48:00,400
that the Maori had so much moa meat
489
00:48:00,560 --> 00:48:05,150
that they could afford to throw away
sections like this.
490
00:48:05,650 --> 00:48:09,620
The Maori not only reduced
the number of moa by hunting,
491
00:48:09,820 --> 00:48:14,370
they also burnt down the forests
on which the moas depended.
492
00:48:14,660 --> 00:48:19,830
And so, by the time the Europeans arrived here
in the 18th century,
493
00:48:20,000 --> 00:48:23,880
the last of the moas
had been extinct for some 200 years.
494
00:48:26,510 --> 00:48:31,970
But in the millions of years that have passed
since New Zealand was isolated as islands,
495
00:48:32,180 --> 00:48:35,430
many more modern creatures have arrived here.
496
00:48:35,640 --> 00:48:40,850
They've got here, as they've managed
to get to islands all over the world, by flying.
497
00:48:42,360 --> 00:48:44,940
Some have changed only a little
since they arrived.
498
00:48:45,110 --> 00:48:49,200
The kereru is still quite clearly a kind of pigeon
499
00:48:56,160 --> 00:49:00,210
And this, the kea, is still recognisably a parrot.
500
00:49:01,290 --> 00:49:03,250
Its ancestors came, doubtless,
501
00:49:03,420 --> 00:49:07,710
from that great parrot homeland, Australia,
1,000 miles away.
502
00:49:07,920 --> 00:49:11,590
Since it's been here,
it's probably changed its habits a good deal,
503
00:49:11,760 --> 00:49:14,470
for it's taken up life in the cold, high mountains
504
00:49:14,680 --> 00:49:19,310
where it feeds on berries and roots,
buds and insects.
505
00:49:28,690 --> 00:49:33,070
It has also, with that adaptability of diet
characteristic of islanders,
506
00:49:33,240 --> 00:49:35,280
become a general scavenger,
507
00:49:35,490 --> 00:49:39,410
and will even feed on carrion
like a crow or small vulture.
508
00:49:41,500 --> 00:49:46,170
One parrot, here, however,
has been changed extremely by island life.
509
00:49:47,210 --> 00:49:48,590
The kakapo.
510
00:49:49,090 --> 00:49:52,180
There are no ground-living
leaf-eating mammals on the island,
511
00:49:52,340 --> 00:49:55,970
so this has become
a kind of parrot-equivalent of a rabbit.
512
00:49:59,810 --> 00:50:05,520
It's extremely nervous, nocturnal,
and it lives on vegetation,
513
00:50:05,730 --> 00:50:11,240
but it shows those two characteristics
of island-living creatures.
514
00:50:11,990 --> 00:50:15,030
It has lost its powers of flight,
515
00:50:15,410 --> 00:50:22,040
so its only defence
is to freeze motionless as it's doing now.
516
00:50:23,170 --> 00:50:26,380
And secondly, it's a giant.
517
00:50:27,340 --> 00:50:31,090
It's the biggest of all the parrots by weight.
518
00:50:32,380 --> 00:50:36,510
A big one can weigh over three kilos.
519
00:50:38,140 --> 00:50:45,270
It also shows only too vividly
a third characteristic of island-living forms:
520
00:50:46,100 --> 00:50:48,900
Their extreme vulnerability.
521
00:50:49,360 --> 00:50:55,740
When their islands are invaded by outsiders,
they often have no defence.
522
00:50:56,620 --> 00:51:01,450
The kakapo's troubles started
when the Polynesians first came to New Zealand.
523
00:51:01,870 --> 00:51:07,000
They brought a kind of rat
which may have preyed upon the nestling kakapo,
524
00:51:07,170 --> 00:51:10,710
and the Polynesians themselves hunted it.
525
00:51:12,090 --> 00:51:16,590
The real catastrophe came
when Europeans arrived,
526
00:51:16,800 --> 00:51:23,640
because they brought with them
those two merciless killers, the stoat and the cat
527
00:51:24,310 --> 00:51:28,940
Against them,
the kakapo had no defence whatever.
528
00:51:29,980 --> 00:51:32,900
Very rapidly, its numbers diminished
529
00:51:33,070 --> 00:51:40,370
until today there are
not more than 60 individual kakapo left.
530
00:51:42,160 --> 00:51:44,290
To give them some chance of survival,
531
00:51:44,580 --> 00:51:50,170
they've been taken to a small offshore island
that has been cleared of cats.
532
00:51:51,000 --> 00:51:56,510
Elsewhere, these domestic pets
that were brought here to catch mice in houses
533
00:51:56,680 --> 00:52:00,180
have run wild in the forests,
and prey on native birds
534
00:52:00,390 --> 00:52:05,310
which have not acquired the right reflexes
to save themselves from its attacks.
535
00:52:31,340 --> 00:52:34,510
Cats are not the only foreign killers here.
536
00:52:34,800 --> 00:52:37,880
Ferrets were imported
for hunting introduced rabbits.
537
00:52:38,340 --> 00:52:40,760
They are domesticated polecats.
538
00:52:41,090 --> 00:52:44,220
Some escaped,
reverted to their wild state and bred.
539
00:52:44,680 --> 00:52:49,100
This one is feeding on a penguin chick
which must have been an easy victim.
540
00:52:49,310 --> 00:52:53,270
None of New Zealand's flightless birds
are safe from them.
541
00:52:55,280 --> 00:52:57,950
People also introduced plant-eating animals.
542
00:52:58,400 --> 00:53:01,490
Possums were brought from Australia as pets.
543
00:53:08,000 --> 00:53:11,790
Rabbits were also imported
to provide meat and fur,
544
00:53:12,130 --> 00:53:15,670
and to put to good use,
as the importers must have thought,
545
00:53:15,960 --> 00:53:19,340
the abundant grass that was going to waste.
546
00:53:19,840 --> 00:53:24,100
And red deer were released in the mountains
to provide hunters with sport.
547
00:53:24,430 --> 00:53:30,060
Yet these seemingly harmless vegetarians
had a catastrophic effect on the native animals.
548
00:53:30,810 --> 00:53:35,230
They grazed so effectively
that they destroyed the trees and bushes.
549
00:53:35,480 --> 00:53:38,780
The soil was washed away
and the forest devastated.
550
00:53:38,940 --> 00:53:43,780
Creatures were robbed of their cover
and vegetation.
551
00:53:45,280 --> 00:53:48,660
The problems of halting this destruction
are very great.
552
00:53:49,000 --> 00:53:52,370
This extraordinary bird is the takahe.
553
00:53:52,710 --> 00:53:56,840
Like the kakapo,
it epitomises the effects of island-living.
554
00:53:57,090 --> 00:54:00,800
It's become a giant,
for it's a rail, like the one in Aldabra,
555
00:54:00,970 --> 00:54:03,050
and the biggest of its family.
556
00:54:03,340 --> 00:54:06,560
It's unique to these islands, it's flightless,
557
00:54:06,720 --> 00:54:10,270
and has virtually no defence against invaders.
558
00:54:10,770 --> 00:54:13,980
At the beginning of this century,
it was thought to be extinct.
559
00:54:14,270 --> 00:54:18,940
Then, after no one had seen a living takahe
for over 50 years,
560
00:54:19,110 --> 00:54:24,110
a small population was discovered
in a remote valley in South Island.
561
00:54:25,120 --> 00:54:27,580
There are about 200 left.
562
00:54:27,910 --> 00:54:32,750
They are unlikely to spread,
for their habitat elsewhere has been destroyed,
563
00:54:33,000 --> 00:54:36,960
and there is the greatest difficulty
in getting them to breed in captivity.
564
00:54:40,210 --> 00:54:47,010
So, unless man is prepared to change his attitude
and become an active protector
565
00:54:47,350 --> 00:54:49,100
as he has done here in New Zealand,
566
00:54:49,350 --> 00:54:52,350
those strange specialised islanders
567
00:54:52,520 --> 00:54:57,860
are doomed to the fate of the first
island-living creature that man exterminated
568
00:54:58,020 --> 00:55:01,320
and become as dead as the dodo.
569
00:55:01,990 --> 00:55:04,740
Of course, not all the creatures
that you find on islands
570
00:55:04,910 --> 00:55:07,780
necessarily spend all their time there.
571
00:55:08,120 --> 00:55:13,460
Some like those tough international
travellers over there, the gannets,
572
00:55:13,660 --> 00:55:15,750
just come here for lodging.
573
00:55:17,330 --> 00:55:20,130
They, like the frigates
and the boobies of Aldabra,
574
00:55:20,300 --> 00:55:23,550
the noddies and the terns
of a thousand tropical atolls,
575
00:55:23,720 --> 00:55:29,720
find their food, not on the islands where
they come to nest, but in the surrounding seas.
56581
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