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A forest on the lower slopes of the Andes.

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A spectacled bear is looking for a snack.

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0ne of the problems
that faces us and all animals

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00:02:04,086 --> 00:02:06,077
is finding enough to eat.

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Being animals and not plants,
we only feed on other living organisms,

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00:02:10,766 --> 00:02:14,759
and, by and large,
other living organisms don't welcome that.

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Animals run away or defend themselves,

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and even plants have surprisingly effective ways
of preventing anyone from stealing their leaves.

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I'm in the South American rainforest -

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the richest proliferation of life on Earth -

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so you might think that here
I'd have no difficulty in finding food,

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particularly if I was prepared to be vegetarian.

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But it's not as simple as that.

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These woolly spider monkeys
are taking their first meal of the day.

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It might seem to be a gentle, peaceful scene,

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but, in fact, it's a battleground.

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The tree defends itself
by developing poison in its leaves,

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but when newly-sprouted, they're just edible,

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so the monkeys have to select
which they eat with great care.

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Even with great discrimination,
they will swallow a little poison,

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and now they've had
as much as they can tolerate.

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They move off and find another kind of tree.

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This too has poison in its leaves,
but it's a slightly different kind,

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so the monkeys can take
a second course of their meal,

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providing they continue to be careful.

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Another drawback to eating leaves
is that they're not very nutritious,

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and the monkey has to eat
great quantities to sustain itself.

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Huge meals require huge stomachs
to hold them,

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and that means that the monkeys
are not the most nimble of movers

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up in the branches.

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After an hour or so of feeding,

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the need to digest their vast meals
demands that they take time off

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and have a siesta.

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Eating leaves is not easy.

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The small red panda of the Himalayas

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is one of the few animals that has beaten
the defences of the bamboo.

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Its leaves are not only very fibrous
but armed with tiny blades of silica,

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so sharp that they can cut flesh.

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But the panda's digestion
is able to cope with them

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and the reward is that it has
all the bamboo it can eat,

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since so few other animals will touch it.

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Bamboo also grows in Madagascar,

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and here the rare
golden bamboo lemur feeds on it.

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It scissors through the coarse
outer leaves on the stem

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to reach the marginally softer
and more succulent ones within.

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Its preferred choice is not so much the leaves

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as the new shoots that come up
through the ground like spears.

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They, of course, are particularly
important to the plant

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and it loads them with cyanide.

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Eating one of these uncooked could kill a man.

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The bamboo lemur can only eat them
because its stomach produces special juices

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that neutralise the poison.

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But developing this ability has a price -

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the bamboo lemur now can't eat much else.

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So if the bamboo disappears, so does the lemur.

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The greatest plunderers of leaves,
however, are insects.

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They're the most numerous creatures on Earth

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and a high proportion of them -
as caterpillars or adults - eat leaves.

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The evidence is everywhere.

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Insects are also fussy feeders.

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A female lays her eggs on the kind of plant
her caterpillar's digestion can cope with,

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so when they hatch, they find the food they need
immediately in front of them.

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They are little more than eating machines -

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a pair of jaws attached to a bag-like gut.

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No complications with wings and sex organs.

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Those will come later when they turn into adults.

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Now it's just munch, munch, munch.

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Plague beetles have a special way
of beating a plant's poison.

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Since it's costly to produce,

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many plants only keep small stocks

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and deter grazers by rapidly deploying it
to the point of attack.

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But plague beetles descend
on a plant in such numbers

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that its poison must be shared between many,

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and each beetle only gets
a tiny and tolerable amount.

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It's true that each one only gets a small meal,

76
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but as soon as they've finished with this plant,

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they move on to another.

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The milkweed invests much more
in its defences.

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Its abundant and very poisonous sap - latex -

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is piped along special veins
and is immediately available everywhere.

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But this beetle has worked out
how to deal with that.

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It punctures the pipeline
running along the leaf rib,

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so that the milky latex leaks out.

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As a result, the poison never
reaches the end of the leaf,

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and there the beetle can feed in safety.

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The latex also seals a plant's wounds,
because it rapidly solidifies in air.

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But since it can't reach here,

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the beetle doesn't have any problem
with gummed-up jaws.

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Marmosets also deliberately wound plants.

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They repeatedly gouge grooves in the trunks
of trees that, when damaged, exude resin.

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Like the milkweed's latex,
resin seals off the tree's injuries,

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preventing loss of sap and the entry of infections.

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But unlike latex, it's not poisonous.

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0n the contrary, it's full of sugars
and rather good to eat.

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And the marmosets love it.

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So the tree's measures to defend itself
have actually resulted in encouraging its injury.

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Not all plants are so uncooperative.

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Some actually encourage animals
to come and feed from them,

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and advertise the fact
they've got food with brilliant displays,

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as these poppies are doing.

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This is not, of course,
generosity on their part, but self-interest.

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The food they have to offer is a bribe

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to persuade the animals to act as couriers.

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They need to have their pollen
ferried across to other flowers.

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Pollen in itself is edible.

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Bumblebees have a great taste for it.

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Bees have a complex arrangement
of cones and brushes on their hind legs

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with which they gather pollen

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and pack it into baskets on their thighs.

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As they move from flower to flower,

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the pollen that brushes
onto their bodies on one flower

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brushes off on another,
and the plant's purpose is accomplished.

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Pollen, packed with genetic material,

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is a complex and expensive commodity,

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and many flowers offer a cheaper bribe -

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nothing more than sweetened water.

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Nectar.

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The plant produces it from nectaries
usually in the heart of the flower,

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so that thirsty insects, to reach it,

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have to brush past the stamens,
collecting a dusting of pollen.

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In temperate lands, flowers can only be found

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in the spring and summer when there's no frost,

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so insects that shelter from the winter, in nests,

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have to build up stocks as quickly as they can.

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They have, in fact, to be as busy as bees.

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In the tropics, on the other hand,

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there are always plants
of one kind or another in bloom,

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so it's possible to feed
on nectar throughout the year,

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and many animals do.

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This vine, combretum, is particularly generous.

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Almost any animal that wants nectar
can get it without difficulty

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when the plant is in flower.

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Many birds which feed on fruit,
berries, or even insects,

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come to drink from it.

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And so do monkeys.

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The smaller kinds - squirrel monkeys,
tamarins and marmosets -

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can clamber right out onto the thinner branches.

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Even the much bigger hefty capuchins,

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which feed on fruit, nestling birds,
lizards and even, on occasion,

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small monkeys, enjoy a sweet drink.

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As all the monkeys feed,

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so the stamens brush the fur on their face,

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and the pollen is on its way to another flower.

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Nectar feeding has its problems.

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A heliconia flower, like this one,

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produces only a little nectar at a time.

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So if a hummingbird comes to feed from here,

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it has to go elsewhere to get more,

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so bringing about the heliconia's
purpose of cross-pollination.

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And it takes a little time
for the heliconia to produce more nectar,

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so if the hummingbird comes back
too soon it's wasted its journey;

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too late, and another bird
may have stolen the nectar.

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As a consequence,
hummingbirds patrol a group of these plants,

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visiting each flower in strict rotation

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to an accurately timed schedule.

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And he was right on time.

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Hummingbirds are among the few animals

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that live almost entirely on nectar -
they also eat small insects -

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and they've developed special
equipment to collect it.

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The wings have joints that enable them
to beat with a whirling motion,

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giving perfect control in the air.

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So it can hover in front of a flower
and insert its beak with absolute precision.

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The tongue is long and thread-like

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and flicks in and out thirteen times a second.

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But this specialisation

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means that hummingbirds
can feed on almost nothing else,

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and that puts them in the plant's power.

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It may seem that this hummingbird
is deciding which flower to drink from,

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but you could argue that the plant,
by controlling nectar production,

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is dictating the movements of the hummingbird.

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Many hummingbirds have a bill
which, in its length and curvature,

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exactly matches the shape and dimensions
of the particular flower on which they mostly feed.

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The violet sabre-wing's beak
fits into the columnea flower

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as accurately as a dagger
slipping into a scabbard.

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And the flower has stamens placed
in precisely the position needed

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to put a dab of pollen on the bird's forehead.

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So the sabre-wing and columnea
have become partners.

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This suits columnea
because its pollen is not taken

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by hummingbirds feeding
on other kinds of flowers, and so wasted.

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And it suits the sabre-wing

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because, since no other bird
has this shape of bill,

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it has all the columnea nectar to itself.

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But not quite.

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The mountain gem hummer has other ideas.

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It's waiting for the flower's partner to leave.

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Its bill is too short to reach
the nectar as the sabre-wing does.

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00:17:30,326 --> 00:17:34,285
With a thrust from its wings,
it tries to pierce the flower.

188
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This time, it holds the flower with its feet.

189
00:17:54,526 --> 00:17:58,041
It's broken in. Columnea has been burgled.

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00:18:02,086 --> 00:18:06,045
Another thief, only too eager
to take advantage of a flower.

191
00:18:08,166 --> 00:18:10,634
Indian langur monkeys.

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00:18:12,926 --> 00:18:15,565
The flowers of the flame-of-the-forest

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00:18:15,726 --> 00:18:19,878
are protected from raiders by being placed
at the ends of long, thorny twigs,

194
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so they're reserved
for their particular pollinators, birds.

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But langurs find them very tempting.

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This of course is disastrous for the tree.

197
00:18:49,046 --> 00:18:53,039
Its complex, subtle mechanisms
for getting its seeds fertilised,

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evolved over millions of years,
are being chewed to pieces.

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00:19:07,246 --> 00:19:09,601
Even the remotest flowers aren't safe,

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for the young babies, braving the thorns,

201
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can clamber right out onto the thinnest
branches without them breaking.

202
00:19:17,366 --> 00:19:20,438
In the continuous struggle
between animals and plants,

203
00:19:20,606 --> 00:19:24,315
this round has certainly been lost by the plant.

204
00:19:33,926 --> 00:19:38,204
In the lush forests of the tropics,
where flowers bloom all year,

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animals that feed on nectar
can always find a drink somewhere.

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00:19:42,806 --> 00:19:47,402
But in other parts of the world,
where the winters are bitterly cold,

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00:19:47,566 --> 00:19:49,841
or here in the deserts of Australia,

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00:19:50,006 --> 00:19:52,839
where flowers only bloom after brief rains,

209
00:19:53,006 --> 00:19:57,204
animals that rely on nectar
have to have some way of storing it

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00:19:57,366 --> 00:19:59,926
to last them through the hard times.

211
00:20:00,086 --> 00:20:04,796
These mulga trees produce nectar
on which ants feed,

212
00:20:04,966 --> 00:20:08,481
and they have the most extraordinary larders.

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00:20:12,846 --> 00:20:18,204
The galleries of their nests lie four feet or so
below the surface of the ground.

214
00:20:24,246 --> 00:20:27,522
These golden globes hanging from the roof

215
00:20:27,686 --> 00:20:30,723
are their storage pots, full of honey.

216
00:20:30,886 --> 00:20:32,444
Each one is alive -

217
00:20:32,606 --> 00:20:36,679
an ant with an abdomen
expanded to the size of a grape.

218
00:20:37,366 --> 00:20:40,244
The small dark flecks are the hard plates

219
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which protect the body of a normal-sized ant.

220
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It's the membrane between them
that has stretched.

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These bloated individuals
are almost totally inactive,

222
00:20:51,886 --> 00:20:55,196
so they consume
little of the honey that they hold.

223
00:20:55,366 --> 00:20:57,675
It is drunk by the busy workers

224
00:20:57,846 --> 00:21:00,485
who, when there's little food above ground,

225
00:21:00,646 --> 00:21:04,764
come down here and induce
the honeypots to regurgitate it.

226
00:21:13,366 --> 00:21:16,563
The workers also tend the swollen bodies,

227
00:21:16,726 --> 00:21:19,240
keeping them well-groomed and clean.

228
00:21:22,526 --> 00:21:26,075
During good times, the workers
collect all the nectar they can

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00:21:26,246 --> 00:21:30,603
and take it down to the larders
to top up the colony's storage jars

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00:21:30,766 --> 00:21:33,644
by feeding it to them drop by drop.

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00:21:53,926 --> 00:21:58,841
The people who have roamed these deserts
for millennia - Aborigines -

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00:21:59,006 --> 00:22:02,715
have always valued these ants
as one of their few sources of sugar,

233
00:22:02,886 --> 00:22:05,798
and they eat them just as they are.

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00:22:08,366 --> 00:22:10,084
Mmmm.

235
00:22:13,286 --> 00:22:15,197
Mmmm.

236
00:22:15,366 --> 00:22:20,235
It's liquid, warm, and marvellously sweet.

237
00:22:24,166 --> 00:22:25,838
A few weeks after flowering,

238
00:22:26,006 --> 00:22:29,681
many plants tempt animals
with another food - fruit.

239
00:22:29,846 --> 00:22:31,837
They have another problem.

240
00:22:32,006 --> 00:22:34,884
Their seeds are formed
and need to be distributed.

241
00:22:35,046 --> 00:22:37,560
By wrapping them in sweet edible pulp,

242
00:22:37,726 --> 00:22:40,240
they recruit lots of animals to do the job.

243
00:22:48,006 --> 00:22:52,761
The trees dissuade animals from collecting
the fruit before the seeds are fully developed

244
00:22:52,926 --> 00:22:56,316
by not producing the sugars in it
until the last moment.

245
00:22:56,486 --> 00:23:00,559
So unripe fruit tastes bitter
and is really not worth picking.

246
00:23:08,686 --> 00:23:12,395
To indicate when it is,
the fruit often changes colour.

247
00:23:14,326 --> 00:23:17,318
Squirrel monkeys are primarily fruit eaters.

248
00:23:17,486 --> 00:23:20,319
They move about in large groups of 40 or so,

249
00:23:20,486 --> 00:23:25,355
and must wander over a great area
to find all the fruit they need.

250
00:23:27,206 --> 00:23:30,357
Capuchins, on the other hand,
live in small families,

251
00:23:30,526 --> 00:23:33,677
each with its own patch of forest.

252
00:23:33,846 --> 00:23:35,438
They eat all kinds of things,

253
00:23:35,606 --> 00:23:39,201
but if there's fruit in their territory,
they'll know about it.

254
00:23:42,526 --> 00:23:46,041
So although the squirrel monkeys
are frightened of the bigger capuchins,

255
00:23:46,206 --> 00:23:48,800
they still follow them as they forage.

256
00:24:03,766 --> 00:24:08,635
There may be something for the capuchin -
a lizard maybe - but no fruit.

257
00:24:09,926 --> 00:24:13,839
So the squirrel monkey
is not interested and must wait.

258
00:24:20,526 --> 00:24:22,562
The capuchin moves on.

259
00:24:28,686 --> 00:24:31,439
And the squirrel monkeys follow.

260
00:24:36,766 --> 00:24:39,519
As the capuchins get near the fruiting tree,

261
00:24:39,686 --> 00:24:42,996
the squirrel monkeys,
perhaps smelling the fruit, scamper ahead

262
00:24:43,166 --> 00:24:48,843
to try and get to it before the more powerful
capuchins reach it and drive them off.

263
00:25:01,366 --> 00:25:05,359
Now they must grab as much as they can
as quickly as they can.

264
00:25:20,246 --> 00:25:22,043
The capuchins arrive.

265
00:25:45,526 --> 00:25:47,994
It's time for the squirrel monkeys to go.

266
00:25:48,166 --> 00:25:52,000
They take with them,
inside their stomachs, the tree's seeds.

267
00:25:52,166 --> 00:25:56,478
They pass through the monkeys
and then, some distance away,

268
00:25:56,646 --> 00:26:00,116
they're deposited
with a convenient dollop of fertiliser.

269
00:26:03,326 --> 00:26:06,557
Seeds themselves are packed with nourishment,

270
00:26:06,726 --> 00:26:08,717
so plants enclose them in shells

271
00:26:08,886 --> 00:26:11,605
which can be strong enough
to defeat even a mangabey.

272
00:26:12,326 --> 00:26:14,317
Victory to the plant.

273
00:26:15,926 --> 00:26:19,043
But the chimp is so clever, it can crack them.

274
00:26:21,766 --> 00:26:24,041
Victory to the animal.

275
00:26:27,846 --> 00:26:33,045
Sharp teeth enable an agouti
to chisel into the acorn of a tropical oak.

276
00:26:36,166 --> 00:26:38,157
In spite of the acorn's armour,

277
00:26:38,326 --> 00:26:41,602
it seems that the oak has lost this contest.

278
00:26:42,446 --> 00:26:43,925
But not totally.

279
00:26:44,086 --> 00:26:48,045
The oak produces more acorns
than the agouti can eat immediately.

280
00:26:48,206 --> 00:26:52,245
Those that it can't,
it carries away and buries for later.

281
00:27:01,926 --> 00:27:04,759
But an agouti's memory is not infallible.

282
00:27:04,926 --> 00:27:07,599
0ccasionally, it will forget about an acorn,

283
00:27:07,766 --> 00:27:10,644
which may germinate and grow into a new oak.

284
00:27:10,806 --> 00:27:13,320
That will be a victory for the plant.

285
00:27:16,646 --> 00:27:20,400
Perhaps the most extraordinary
of all tools for nut eating

286
00:27:20,566 --> 00:27:25,003
is wielded by a strange
Madagascan lemur, the aye-aye.

287
00:27:32,326 --> 00:27:37,958
First it gnaws a hole, then scoops out
the contents with this long bony probe,

288
00:27:38,126 --> 00:27:42,881
which is, in fact, its finger,
but one quite unlike its others.

289
00:27:46,766 --> 00:27:51,078
This curious digit serves
just as well for eating a grub.

290
00:27:51,246 --> 00:27:54,841
The aye-aye uses it to mash up
the body in its burrow,

291
00:27:55,006 --> 00:27:57,520
and then flicks out the purée.

292
00:28:02,846 --> 00:28:05,804
The spiny pocket mouse has a double problem.

293
00:28:05,966 --> 00:28:10,403
The seed it's gnawing is not only
hard-shelled but packed with poison.

294
00:28:10,566 --> 00:28:14,275
The mouse does nothing more
than puncture the shell.

295
00:28:14,446 --> 00:28:18,678
It then tucks it into its cheek
and carries it back to its burrow.

296
00:28:20,086 --> 00:28:23,396
The hole in the shell
stimulates the seed to germinate,

297
00:28:23,566 --> 00:28:26,717
and the tender white shoot
that leaves the protection of the shell

298
00:28:26,886 --> 00:28:28,877
is poison-free.

299
00:28:38,686 --> 00:28:43,396
The macaw has, almost certainly,
the most powerful nutcracker of all.

300
00:28:43,566 --> 00:28:47,161
It can demolish even the most resistant of nuts.

301
00:28:47,326 --> 00:28:51,365
Many of the seeds macaws eat
are also filled with poison,

302
00:28:51,526 --> 00:28:54,199
yet this doesn't seem to upset them.

303
00:28:54,366 --> 00:28:56,357
How do they survive?

304
00:28:59,726 --> 00:29:03,002
Every day, they make long journeys
through the forest

305
00:29:03,166 --> 00:29:06,158
to dose themselves with a special antidote.

306
00:29:15,846 --> 00:29:18,565
Macaws usually fly in pairs.

307
00:29:18,726 --> 00:29:22,685
0nly in such places as this
do they assemble in flocks.

308
00:29:35,246 --> 00:29:38,124
They've come to collect their medicine.

309
00:29:38,286 --> 00:29:42,757
The regular presence of so many birds
attracts eagles and other predators,

310
00:29:42,926 --> 00:29:45,918
so before the macaws come out of the trees,

311
00:29:46,086 --> 00:29:48,441
they want to be sure that it's safe to do so.

312
00:29:48,606 --> 00:29:53,521
They wait for one bird,
braver than the rest, to make the first move.

313
00:29:55,326 --> 00:29:59,080
There it goes. And this is what they're after.

314
00:30:00,126 --> 00:30:01,525
Kaolin.

315
00:30:01,686 --> 00:30:04,041
The soil in this river bank is rich in it.

316
00:30:04,206 --> 00:30:08,961
Several kinds of parrots and macaws
come here every day from miles around

317
00:30:09,126 --> 00:30:11,117
to take the treatment.

318
00:30:18,166 --> 00:30:20,999
Kaolin combats acidity in the stomach,

319
00:30:21,166 --> 00:30:23,760
absorbs and neutralises poisons.

320
00:30:23,926 --> 00:30:27,919
As a bonus, this clay is rich
in calcium and sodium,

321
00:30:28,086 --> 00:30:31,442
which is lacking in diets
that consist of fruit and nuts.

322
00:30:58,166 --> 00:31:02,921
So eating plants poses more problems
than one might think.

323
00:31:03,086 --> 00:31:08,877
But eating other animals, even small
defenceless ones, also has its difficulties.

324
00:31:10,446 --> 00:31:13,040
It's dawn on the east coast of England,

325
00:31:13,206 --> 00:31:17,165
the middle of winter and food is very scarce.

326
00:31:17,326 --> 00:31:22,195
But behind me is a huge
and abundantly stocked larder.

327
00:31:22,366 --> 00:31:25,039
Its doors have been shut
for the past three hours,

328
00:31:25,206 --> 00:31:29,563
but now the tide is on the turn,
and for a horde of hungry animals,

329
00:31:29,726 --> 00:31:31,603
their waiting is almost over.

330
00:31:34,166 --> 00:31:38,159
Tens of thousands of knot and dunlin
have assembled on a lagoon

331
00:31:38,326 --> 00:31:40,601
on the other side of the sand dunes.

332
00:32:04,246 --> 00:32:07,921
They've sensed that the tide
has exposed a mudbank.

333
00:32:08,086 --> 00:32:10,361
Breakfast is served.

334
00:32:20,926 --> 00:32:25,477
Millions of tiny molluscs are buried
just below the surface of this mud

335
00:32:25,646 --> 00:32:29,321
and the birds are feeling for them with their bills.

336
00:32:38,846 --> 00:32:41,155
Abundant though the food is out there,

337
00:32:41,326 --> 00:32:44,159
collecting it is a very dangerous business.

338
00:32:44,326 --> 00:32:46,521
It's very exposed on the mudflats -

339
00:32:46,686 --> 00:32:49,154
there's nowhere to hide,
nothing to dodge behind,

340
00:32:49,326 --> 00:32:54,241
and the birds deal with that problem
by sticking together in tight flocks.

341
00:32:54,406 --> 00:32:59,605
That way, each bird has a thousand eyes
ready to spot danger.

342
00:33:11,526 --> 00:33:16,998
But if that is such a good idea,
why is this redshank out on its own?

343
00:33:20,846 --> 00:33:24,122
It's hunting, not by touch, but by sight,

344
00:33:24,286 --> 00:33:28,677
and it's searching for its favourite food -
small shrimp-like crustaceans.

345
00:33:28,846 --> 00:33:33,362
If they are alarmed by ripples or vibrations
produced by many moving feet,

346
00:33:33,526 --> 00:33:37,155
they will disappear into the mud
where the redshank can't see them,

347
00:33:37,326 --> 00:33:39,317
and so can't find them.

348
00:33:41,766 --> 00:33:45,645
So if a redshank wants to catch
this more swiftly-moving food,

349
00:33:45,806 --> 00:33:49,481
it has to forage by itself, despite the risks.

350
00:33:54,326 --> 00:33:58,877
And if it does become a little alarmed,
it just squats.

351
00:34:02,166 --> 00:34:06,364
Some waters are so rich in food,
there's plenty for everybody.

352
00:34:06,526 --> 00:34:10,678
0n this Indian lagoon,
there are storks, herons and egrets,

353
00:34:10,846 --> 00:34:13,155
openbills and spoonbills.

354
00:34:13,326 --> 00:34:16,159
Each has its own particular beak technique

355
00:34:16,326 --> 00:34:18,476
with which to catch its favoured prey -

356
00:34:18,646 --> 00:34:22,321
probing and sieving, scything and stabbing.

357
00:35:07,246 --> 00:35:10,955
Even parts of the open sea,
like this bay in the West Indies,

358
00:35:11,126 --> 00:35:13,799
at certain times become so thick with fish

359
00:35:13,966 --> 00:35:17,117
that they can support great flocks of fishermen.

360
00:35:32,166 --> 00:35:35,556
Barracuda - among the most
ferocious hunters in the sea.

361
00:35:35,726 --> 00:35:39,958
They regularly drive shoals
of small fish into the bay.

362
00:35:50,566 --> 00:35:52,921
(SCREECHING)

363
00:36:16,766 --> 00:36:18,757
The pelicans can tackle the shoals

364
00:36:18,926 --> 00:36:21,804
even when they're a foot or two
beneath the surface.

365
00:36:41,086 --> 00:36:45,477
But a pelican can only swallow
the fish it's scooped up in its bill

366
00:36:45,646 --> 00:36:47,876
if it lets the water drain out first.

367
00:36:48,046 --> 00:36:51,118
To do that, it must open its beak slightly,

368
00:36:51,286 --> 00:36:54,164
and that is the moment the gulls are waiting for.

369
00:37:20,766 --> 00:37:24,918
Few places on land offer quite
the density and richness of animal food

370
00:37:25,086 --> 00:37:28,044
that can be found
in parts of the sea such as this.

371
00:37:28,206 --> 00:37:31,960
But one kind of land animal
does swarm in vast numbers,

372
00:37:32,126 --> 00:37:36,563
and this little long-eared tenrec
from Madagascar is in search of them.

373
00:37:44,366 --> 00:37:46,243
They can be sniffed for,

374
00:37:46,406 --> 00:37:49,478
but the tenrec's huge ears
also help to locate them,

375
00:37:49,646 --> 00:37:53,924
for they make a faint rustling noise
as they scurry along their pathways.

376
00:38:00,126 --> 00:38:01,445
Termites.

377
00:38:01,606 --> 00:38:05,394
The juicy, soft-bodied workers
are largely defenceless.

378
00:38:06,366 --> 00:38:08,755
But with them come soldiers.

379
00:38:08,926 --> 00:38:13,636
This kind squirt noxious chemical sprays
from nozzles on their heads.

380
00:38:29,766 --> 00:38:32,234
The tenrec, with its sensitive nose,

381
00:38:32,406 --> 00:38:35,000
can tolerate a certain amount of chemical spray,

382
00:38:35,166 --> 00:38:38,078
but after a while it just has to come up for air.

383
00:39:04,366 --> 00:39:07,438
Termites are hugely abundant in the tropics,

384
00:39:07,606 --> 00:39:11,235
and many different kinds of animals
collect them when they get the chance.

385
00:39:18,606 --> 00:39:22,679
A small gecko in the deserts of Australia
eats little else.

386
00:39:22,846 --> 00:39:24,996
The problem is those soldiers.

387
00:39:25,166 --> 00:39:27,521
But it is such a fastidious and accurate feeder,

388
00:39:27,686 --> 00:39:31,998
it can avoid them and pick out
the defenceless workers one by one.

389
00:39:40,606 --> 00:39:43,074
0f all food-collecting devices,

390
00:39:43,246 --> 00:39:47,637
the most ingenious and elegant
must be the webs of orb spiders.

391
00:39:47,806 --> 00:39:50,559
It's nearly always the females who build them.

392
00:39:52,766 --> 00:39:58,159
0ne starts by rigging filaments of silk
across a flyway used by insects.

393
00:40:10,926 --> 00:40:14,157
Around the spokes,
using silk of a different kind,

394
00:40:14,326 --> 00:40:17,079
she sets a spiral mesh.

395
00:40:18,366 --> 00:40:21,676
As she secures each section, she twangs it,

396
00:40:21,846 --> 00:40:23,677
so that the glue with which it's coated

397
00:40:23,846 --> 00:40:26,599
breaks up into a line of sticky beads.

398
00:40:34,006 --> 00:40:38,238
0ne of the biggest of these webs,
which may be two yards across,

399
00:40:38,406 --> 00:40:41,443
is constructed by the nephila spider.

400
00:40:44,526 --> 00:40:46,118
She is huge.

401
00:40:46,286 --> 00:40:50,518
Her legs can span six inches
and she's virtually blind.

402
00:40:52,006 --> 00:40:55,681
A fly blundering into her web is quickly seized.

403
00:40:58,006 --> 00:41:00,281
She rapidly injects it with a venom

404
00:41:00,446 --> 00:41:02,960
that will liquefy the contents of its body.

405
00:41:07,606 --> 00:41:09,801
She then wraps it up in silk

406
00:41:09,966 --> 00:41:13,754
and parks it on the web
to allow the venom to take effect.

407
00:41:33,446 --> 00:41:36,643
But nephila is not alone on her web.

408
00:41:37,606 --> 00:41:41,758
Argyrodes is tiny,
much smaller even than the fly.

409
00:41:41,926 --> 00:41:44,724
She could easily become a meal for nephila.

410
00:41:44,886 --> 00:41:49,721
She too is blind, but she's also
felt the vibrations of the fly.

411
00:41:50,926 --> 00:41:53,838
With what seems like suicidal recklessness,

412
00:41:54,006 --> 00:41:57,442
she approaches nephila,
still feasting on her prey.

413
00:42:04,926 --> 00:42:09,158
And she too begins to eat food
that nephila not only caught,

414
00:42:09,326 --> 00:42:11,886
but has conveniently pre-digested.

415
00:42:14,246 --> 00:42:16,840
Another capture calls nephila away.

416
00:42:24,606 --> 00:42:27,996
0nce again, she stabs the fly, trusses it up

417
00:42:28,166 --> 00:42:30,999
and carries it away
to hang on the side of the web.

418
00:42:31,166 --> 00:42:33,043
She'll eat that later.

419
00:42:38,006 --> 00:42:41,794
Argyrodes seems well aware of what's going on.

420
00:42:51,086 --> 00:42:54,396
As soon as nephila has hung up
her latest catch,

421
00:42:54,566 --> 00:42:58,002
argyrodes starts trying to discover its position

422
00:42:58,166 --> 00:43:00,521
by pulling the web filaments.

423
00:43:15,366 --> 00:43:18,961
Nephila has returned to finish her first meal.

424
00:43:25,166 --> 00:43:29,603
Meanwhile, argyrodes has run a line
from the top of the web to the fly,

425
00:43:29,766 --> 00:43:31,757
which she's now cutting loose.

426
00:43:53,846 --> 00:43:57,839
0nce the fly is free of the web,
she lowers it down.

427
00:44:12,366 --> 00:44:15,915
The stolen fly is now hanging entirely free.

428
00:44:16,086 --> 00:44:18,725
Nephila won't be able to reclaim it now,

429
00:44:18,886 --> 00:44:25,200
but argyrodes must get it to a place
where she can feed on it in safety.

430
00:44:25,606 --> 00:44:28,643
Step by step, she heaves it up.

431
00:44:28,806 --> 00:44:31,479
Her theft is complete.

432
00:44:36,846 --> 00:44:40,805
Tropic birds nest on this cliff
in Tobago in the West Indies.

433
00:44:40,966 --> 00:44:42,763
They're magnificent fliers,

434
00:44:42,926 --> 00:44:47,636
able to exploit all the currents
of the air with spectacular ease.

435
00:44:54,366 --> 00:44:55,958
They fish out at sea,

436
00:44:56,126 --> 00:44:59,835
and every day the hard-working
parents return to their nests

437
00:45:00,006 --> 00:45:02,201
with crops full of food for the family.

438
00:45:16,006 --> 00:45:21,763
18th-century frigates were swift, heavily-armed
warships which plundered merchantmen.

439
00:45:21,926 --> 00:45:23,803
These are frigate birds.

440
00:45:27,006 --> 00:45:29,759
The fishing fleet is returning.

441
00:46:25,606 --> 00:46:28,166
The frigate wasn't trying to kill the tropic bird,

442
00:46:28,326 --> 00:46:31,238
only to make it surrender its cargo of fish.

443
00:46:31,406 --> 00:46:34,478
But it'll have to find a less determined victim.

444
00:46:36,006 --> 00:46:40,238
The usual tactic is to come up
astern of the chosen victim

445
00:46:40,406 --> 00:46:42,442
and grab its leg or tail.

446
00:46:51,846 --> 00:46:53,245
It surrenders.

447
00:46:53,406 --> 00:46:56,842
There goes the disgorged fish,
and the frigate catches it.

448
00:47:44,366 --> 00:47:46,482
The frigates aren't always successful.

449
00:47:46,646 --> 00:47:49,444
Watching them, you can't help wondering

450
00:47:49,606 --> 00:47:52,723
if it wouldn't be easier
to catch the fish themselves,

451
00:47:52,886 --> 00:47:54,763
and indeed they often do.

452
00:47:54,926 --> 00:47:58,555
But they seem positively to enjoy a life of piracy.

453
00:48:00,686 --> 00:48:03,564
As to the tropic birds, most of them escape,

454
00:48:03,726 --> 00:48:06,638
and those that are caught only lose a few fish.

455
00:48:06,806 --> 00:48:11,800
But it's only a short step between
robbing your victim and killing him,

456
00:48:11,966 --> 00:48:15,356
for the pirate to become a hunter.

457
00:48:15,526 --> 00:48:18,324
And that raises
a completely new set of problems.

458
00:48:18,486 --> 00:48:22,081
It's those that we'll be looking at
in the next programme.