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00:00:32,937 --> 00:00:35,405
Look up there! See it?

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00:00:46,617 --> 00:00:52,726
I'm looking at one of the most striking
and instantly identifiable animals in the world.

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00:00:52,897 --> 00:00:56,412
A single one is worth about a million pounds.

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00:00:56,577 --> 00:00:58,727
Famously fussy in their feeding,

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00:00:58,897 --> 00:01:01,775
less than a thousand still survive in the wild.

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00:01:01,937 --> 00:01:04,053
Millions are spent on conserving them,

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00:01:04,217 --> 00:01:07,892
and yet increasingly it's the case
that if you want to see one

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00:01:08,057 --> 00:01:10,810
you've to come to a zoo, like this one in Atlanta.

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00:01:11,857 --> 00:01:14,451
It's a giant panda.

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00:01:15,177 --> 00:01:19,932
When it comes to food,
the giant panda is the ultimate specialist.

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00:01:20,097 --> 00:01:24,170
It eats bamboo and virtually nothing else.

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Not many animals can live on such a diet.

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Bamboo is tough, fibrous and very indigestible.

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With no competition, pandas thrived,

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until the bamboo forests in their
native China started to disappear.

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Then with no other food to fall back on,
their population crashed.

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00:01:52,537 --> 00:01:57,008
So the giant panda lives its life on the edge.

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00:01:57,177 --> 00:01:59,452
There are other feeding strategies.

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00:01:59,617 --> 00:02:03,849
Instead of being a specialist,
you can be a generalist, an omnivore,

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00:02:04,017 --> 00:02:08,886
prepared to eat pretty well anything
you can find, animal or vegetable.

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00:02:09,057 --> 00:02:11,651
That strategy has led to some animals

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that are the most successful
and charismatic of all.

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00:02:15,817 --> 00:02:19,856
What does it take to be
an omnivore and who are they?

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Omnivores are the most
adaptable animals in the world.

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00:02:30,017 --> 00:02:33,566
There's no better example
than the North American racoon,

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which is as varied in its diet
as the panda is specialised.

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This remarkable mammal has adapted
to more types of habitat than almost any other.

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The skills that have enabled it
to do so are many,

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but there's one which it shares
with all omnivores:

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the ability to make the most of any opportunity.

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00:03:07,337 --> 00:03:12,252
The racoon owes much of its success
to its inquisitive nature.

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But it also has a special trick up its sleeve...

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00:03:16,537 --> 00:03:19,335
extremely sensitive hands.

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Touch is the racoon's most powerful sense.

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00:03:28,977 --> 00:03:32,333
To process the information
it gets from its hands,

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it uses an unusually large
proportion of its brain,

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about the same as humans use for sight.

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Scientists now believe
that a racoon, through touch,

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00:03:44,057 --> 00:03:46,571
can construct a picture of its surroundings

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that is as complex as that
which we perceive with our eyes.

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00:03:52,417 --> 00:03:56,046
You might say that
the racoon sees with its hands.

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00:03:57,017 --> 00:04:01,772
It can feel the difference between
a rock and a clam in a split second.

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If it touches a crayfish,
which is armed with powerful pincers,

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then this ''second sight'' is clearly very valuable.

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Their extraordinary sense of touch
is not affected by temperature.

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Unlike human beings', racoon hands
retain their sensitivity even in the coldest water,

47
00:04:37,977 --> 00:04:42,255
allowing them to forage in rivers
and streams whatever the season.

48
00:04:46,497 --> 00:04:50,649
Racoons have been around
for nearly two and a half million years,

49
00:04:50,817 --> 00:04:54,856
but the first opportunists
appeared much earlier than that.

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00:05:03,617 --> 00:05:10,329
Being able to eat anything was not
the basic condition of mammals.

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00:05:10,497 --> 00:05:13,807
The very first of them,
contemporaries of the dinosaurs,

52
00:05:13,977 --> 00:05:15,854
small insignificant creatures,

53
00:05:16,017 --> 00:05:19,646
had such tiny teeth
they probably ate little but insects.

54
00:05:19,817 --> 00:05:23,526
Specialist omnivores did eventually appear

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00:05:23,697 --> 00:05:25,813
among the prehistoric mammals.

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One lived here in South Dakota,

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though then the climate
and vegetation was very different.

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It's called Dinohyus,

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00:05:42,777 --> 00:05:47,248
and some experts have likened it
to a kind of killer warthog.

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This animal was as big as a rhino.

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It had a large hairy crest
running down its spine,

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a long snout and a formidable set of teeth.

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00:06:05,857 --> 00:06:09,896
Dinohyus died out
about twenty million years ago,

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but its teeth can tell us what it ate.

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At the back, he had massive flat molars

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that could grind up
almost any kind of vegetation.

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It wasn't a specialised vegetarian,
because the teeth at the front

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didn't have the sharp chisel-like teeth
that an antelope has.

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Neither was it a specialised meat-eater,

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because the teeth in its middle jaw

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are not the slicing, sharp,
dagger-like teeth that a lion has.

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Nonetheless, these are pretty formidable.

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So are the big tusks at the front.

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What you have here is a generalised tool kit

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that enabled the animal
to deal with almost anything.

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Dinohyus may be extinct, but teeth like these
are typical of all living omnivores today.

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The forests of Sulawesi
in Indonesia are haunted

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00:07:21,057 --> 00:07:26,575
by a rare and elusive animal,
almost as prehistoric-looking as Dinohyus.

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To find food here, this animal uses
not touch but another ''supersense'',

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the one possessed by all omnivores.

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The thud of a large pangi fruit
hitting the ground

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might attract the attention
of an animal nearby,

83
00:07:47,377 --> 00:07:51,006
but sounds don't travel far
in these thick forests.

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Scent, however, can drift on a breeze
and be detected from great distances

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00:07:56,817 --> 00:08:00,173
by an animal with a really sensitive nose.

86
00:08:05,737 --> 00:08:09,207
This creature certainly has that.

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00:08:15,497 --> 00:08:19,285
It's a babirusa, and its sense of smell

88
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is probably as good as that
of any omnivore alive or dead.

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There are several here,
attracted by the smell of the ripe pangi.

90
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Males have bizarre teeth in their top jaw

91
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that grow upwards,
right through the flesh of its snout.

92
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The size of these tusks
is a good indicator of strength,

93
00:08:44,177 --> 00:08:47,965
so they determine who gives way to whom.

94
00:08:52,337 --> 00:08:56,216
The pangi fruit may smell good,
but there's a problem -

95
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it contains a poison.

96
00:08:58,377 --> 00:09:01,972
The babirusa, however,
knows how to deal with that.

97
00:09:03,377 --> 00:09:05,607
It visits a clay lick.

98
00:09:08,817 --> 00:09:12,890
Clay containing the right sort
of medicine is not common,

99
00:09:13,057 --> 00:09:15,617
and these licks are few and far between.

100
00:09:16,257 --> 00:09:21,047
A large one like this
attracts babirusa from miles around.

101
00:09:25,417 --> 00:09:30,491
These are the only places where this
rare animal is seen in any numbers.

102
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The clay contains a particular mineral

103
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which helps to neutralise
the toxins in the pangi.

104
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Babirusa, like most omnivores,
live in relatively small groups,

105
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for they specialise in picking up
odd bits and pieces,

106
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which seldom occur in sufficient
concentration to sustain a herd.

107
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So the clay lick, for the babirusa,

108
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is a time when individuals
that otherwise lead lonely lives

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00:10:03,697 --> 00:10:05,688
get to know one another.

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Young males get a chance to test their strength.

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(GRUNTS AND SQUEALS)

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The nose, for any pig, is its greatest asset...

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a multi-purpose tool which not only
locates food but digs it up as well.

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00:10:53,897 --> 00:10:58,652
Wild boar, the European cousin
of the eccentric babirusa,

115
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are unrivalled foragers.

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They are the least fussy of feeders.

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Worms make a tasty snack,

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but pigs know there's plenty of other food here.

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It's just a question of finding it.

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Their memories carry the smells
and images of all sorts of things

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00:11:29,457 --> 00:11:32,847
that they've previously eaten and assessed.

122
00:11:36,537 --> 00:11:41,088
Keeping an open mind means
that nothing will be overlooked.

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Certainly not a decaying pigeon.

124
00:11:52,737 --> 00:11:55,854
Foraging in the woodland
is not difficult in summer,

125
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but what happens when the ground
is hidden beneath a blanket of snow?

126
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Food is now very scarce.

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The carcass of an animal killed
by the hardships of winter is a valuable prize,

128
00:12:12,457 --> 00:12:15,767
but the pigs must continue foraging
in their normal way

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if they're to maintain their strength.

130
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They're not just ploughing
through the snow at random.

131
00:12:22,417 --> 00:12:27,696
They're still guided by their nose,
for smell travels through snow.

132
00:12:32,737 --> 00:12:36,366
And there's an interesting smell...right here.

133
00:12:39,017 --> 00:12:40,689
And here.

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By following their noses, pigs are able
to keep active throughout the winter.

135
00:12:51,257 --> 00:12:54,454
Other opportunists use a different tactic.

136
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They spend the winter asleep
in underground dens

137
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and only appear
when spring brings better weather.

138
00:13:01,417 --> 00:13:04,454
This is the Asiatic racoon dog.

139
00:13:04,897 --> 00:13:09,368
Its legs are so short that it has
difficulty moving through snow,

140
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which may be one reason to hibernate.

141
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It too eats almost anything.

142
00:13:16,417 --> 00:13:20,046
The females need to do so,
for they produce large litters,

143
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and supplying all her babies with milk
makes great demands on the mother.

144
00:13:29,097 --> 00:13:32,294
She's produced fifteen pups.

145
00:13:32,657 --> 00:13:36,445
They all need to put on
considerable weight to survive the winter,

146
00:13:36,617 --> 00:13:40,451
and they'll only be helped by their parents
for eight short weeks.

147
00:13:42,697 --> 00:13:46,770
Their first food, of course,
is their mother's milk.

148
00:13:49,577 --> 00:13:52,774
But very soon they need solid food as well,

149
00:13:52,937 --> 00:13:55,929
and that too has to be provided by Mother.

150
00:14:00,297 --> 00:14:04,688
While she goes off to forage,
the male stays to look after the pups.

151
00:14:04,857 --> 00:14:08,054
Surprisingly, given the size of his family,

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00:14:08,217 --> 00:14:11,687
he does virtually nothing to help feed them.

153
00:14:18,457 --> 00:14:23,053
The female is coming back.
She's caught a small rodent.

154
00:14:25,257 --> 00:14:29,933
Unlike many canids, they do not
regurgitate food for their babies,

155
00:14:30,097 --> 00:14:34,329
and, as mouths hold less than stomachs,
this limits the amount of food

156
00:14:34,497 --> 00:14:36,931
she can bring back on one journey.

157
00:14:37,657 --> 00:14:41,332
As a consequence, she has
to provide her cubs with milk

158
00:14:41,497 --> 00:14:44,011
for twice as long as any other dog does.

159
00:14:52,137 --> 00:14:56,574
She'll make a number of journeys
every day, but most things she brings

160
00:14:56,737 --> 00:14:59,205
are only enough for a single pup.

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00:15:00,657 --> 00:15:03,217
This time she's brought an egg.

162
00:15:03,377 --> 00:15:06,687
The pups haven't yet learned
how to deal with such a strange object.

163
00:15:06,857 --> 00:15:10,088
Is it worth eating, and if so, how?

164
00:15:21,777 --> 00:15:25,406
Yes, it is! And the pups won't forget.

165
00:15:32,457 --> 00:15:36,132
Before long, they must start
foraging for themselves,

166
00:15:36,297 --> 00:15:41,212
with their parents alongside to give
guidance as to what is edible.

167
00:15:43,337 --> 00:15:46,090
They don't always get it right.

168
00:15:49,777 --> 00:15:54,168
They have to learn fast, for each
will have to get as fat as its mother

169
00:15:54,337 --> 00:15:57,488
if it's to survive the long sleep through winter -

170
00:15:57,657 --> 00:15:59,887
and not all the litter will do so.

171
00:16:01,057 --> 00:16:06,609
Racoon dogs store food as fat,
but another omnivore has a different tactic.

172
00:16:11,817 --> 00:16:14,172
(CROWING)

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00:16:15,857 --> 00:16:19,406
Chickens, one of mankind's favourite prey,

174
00:16:19,577 --> 00:16:21,886
which he keeps in unnatural concentrations

175
00:16:22,057 --> 00:16:25,891
to provide himself with fresh meat
and eggs all year round.

176
00:16:28,737 --> 00:16:33,765
In farmyards like this, chickens
are easy targets for any opportunist

177
00:16:33,937 --> 00:16:36,974
determined enough to find its way in.

178
00:16:46,937 --> 00:16:51,886
If there's a weak link in the defences,
a fox will find it.

179
00:16:52,057 --> 00:16:54,730
(PANICKED SQUAWKING)

180
00:17:12,417 --> 00:17:16,092
(TREMENDOUS DIN OF SQUAWKING)

181
00:17:23,697 --> 00:17:27,929
Foxes are frequently blamed
for killing more than they need,

182
00:17:28,097 --> 00:17:31,851
but do they really deserve
such a bloodthirsty reputation?

183
00:17:32,497 --> 00:17:38,015
No. A fox will not waste what it kills,
providing it's not disturbed.

184
00:17:42,137 --> 00:17:46,927
However, it must act quickly if it's to make
the most of such an opportunity.

185
00:17:48,497 --> 00:17:52,888
Few realise that foxes bury their surplus food.

186
00:17:55,337 --> 00:17:58,409
They're saving it for when times get tough.

187
00:18:21,257 --> 00:18:25,011
A vixen will bury carcasses all over her territory.

188
00:18:25,177 --> 00:18:28,647
Later she will use her memory
and keen sense of smell

189
00:18:28,817 --> 00:18:31,695
to find them again and dig them up.

190
00:18:32,777 --> 00:18:35,052
The fox is not a wanton killer,

191
00:18:35,217 --> 00:18:38,766
but an intelligent opportunist who thinks ahead.

192
00:18:46,577 --> 00:18:50,490
Some opportunities are both brief and seasonal.

193
00:18:52,057 --> 00:18:56,972
There's an abundant source of food
in this cave, but only for a few weeks,

194
00:18:57,137 --> 00:19:00,254
and it lies right in its far depths.

195
00:19:01,937 --> 00:19:04,531
Down here, it's totally dark,

196
00:19:04,697 --> 00:19:08,815
and we can only see what goes on
by using infra-red cameras.

197
00:19:10,617 --> 00:19:15,816
Darkness is not a problem for bats,
who navigate by echolocation.

198
00:19:16,097 --> 00:19:21,376
For any other animal, getting around
down here is a serious challenge.

199
00:19:26,377 --> 00:19:29,175
And there's another major obstacle.

200
00:19:29,337 --> 00:19:32,215
Droppings produced
by the vast assemblage of bats

201
00:19:32,377 --> 00:19:36,336
creates an atmosphere thick
with ammonia and fungal spores

202
00:19:36,497 --> 00:19:39,170
that can be fatal to those that inhale them.

203
00:19:40,377 --> 00:19:43,608
This guano accumulating
on the floor of the cave

204
00:19:43,777 --> 00:19:46,132
sustains more than fungus.

205
00:19:46,297 --> 00:19:49,369
There's a living carpet
of flesh-eating beetles and larvae,

206
00:19:49,537 --> 00:19:53,894
which together make short work
of anything they can get hold of.

207
00:19:56,177 --> 00:20:01,695
This is about as hostile an environment
as you'll find anywhere on the planet.

208
00:20:01,857 --> 00:20:06,726
Yet that doesn't deter
an enterprising and unfussy opportunist -

209
00:20:06,897 --> 00:20:08,888
the skunk.

210
00:20:11,377 --> 00:20:14,847
Indeed, skunks seem almost at home here.

211
00:20:15,417 --> 00:20:18,250
They even indulge in a little courtship,

212
00:20:18,417 --> 00:20:22,456
as can happen when a male blunders
into a female in the pitch dark.

213
00:20:23,617 --> 00:20:28,566
What is it that tempts them
down into this repellent place?

214
00:20:31,897 --> 00:20:34,889
The answer is baby bats.

215
00:20:35,497 --> 00:20:40,013
At this age, they are unable to fly,
and in such a jostling crowd

216
00:20:40,177 --> 00:20:42,532
many lose their footholds and fall.

217
00:20:48,177 --> 00:20:51,613
On the ground, the babies are in great danger.

218
00:20:53,697 --> 00:20:58,293
The skunks can see nothing whatever,
so the fallen bats may survive,

219
00:20:58,457 --> 00:21:01,688
if only they can regain
the safety of the rock wall.

220
00:21:14,737 --> 00:21:19,686
But so many bats fall that the skunks
are likely to blunder into enough

221
00:21:19,857 --> 00:21:22,576
to make their visit worthwhile.

222
00:21:27,897 --> 00:21:32,766
In the total darkness, the skunks
can't be sure which end of the bat is which.

223
00:21:32,937 --> 00:21:38,375
So to avoid getting bitten, they roll
the bat on the ground to subdue it.

224
00:21:44,457 --> 00:21:49,212
It's not just skunks that make the most
of this macabre seasonal offering.

225
00:21:49,377 --> 00:21:52,767
The touchy-feely racoons are here too.

226
00:21:53,457 --> 00:22:00,374
It might just be the place for an opportunist
that can see with its hands.

227
00:22:03,017 --> 00:22:06,692
Exactly which sense the skunks and racoons use

228
00:22:06,857 --> 00:22:10,406
to find the bats in the pitch-black cave,
no one really knows.

229
00:22:10,817 --> 00:22:15,891
Smell seems unlikely,
given the overpowering stench of ammonia.

230
00:22:16,337 --> 00:22:20,615
How could a skunk or a racoon
possibly hear the distress calls

231
00:22:20,777 --> 00:22:25,407
of a single baby bat above the deafening
squeaks of several million others?

232
00:22:30,817 --> 00:22:36,335
The most likely answer is that they use
a combination of touch and luck.

233
00:22:37,497 --> 00:22:43,527
Both racoons and skunks must rely on,
literally, bumping into the bats.

234
00:22:45,777 --> 00:22:49,406
This bonanza will only last for about a month.

235
00:22:49,577 --> 00:22:53,809
Then these opportunists will have to revert
to more reliable sources of food.

236
00:22:56,497 --> 00:22:58,567
Elsewhere in the world, however,

237
00:22:58,737 --> 00:23:02,969
making the most of seasonal
abundances is a way of life.

238
00:23:03,137 --> 00:23:06,049
Up here in Alaska during the summer,

239
00:23:06,217 --> 00:23:09,653
a whole succession of different food
becomes available.

240
00:23:09,817 --> 00:23:14,811
There's a spectacular animal here
prepared to sample each of them.

241
00:23:14,977 --> 00:23:17,696
No one dish remains available for very long,

242
00:23:17,857 --> 00:23:20,132
so you have to make
the best of it while you can.

243
00:23:20,297 --> 00:23:24,290
Top of the menu right now is...salmon.

244
00:23:24,737 --> 00:23:27,092
It's the favourite food of the largest

245
00:23:27,257 --> 00:23:30,647
and certainly the most formidable
of all omnivores -

246
00:23:30,817 --> 00:23:32,808
the grizzly bears.

247
00:23:34,817 --> 00:23:39,095
Salmon are plentiful now, but six
months ago, in the middle of winter,

248
00:23:39,257 --> 00:23:41,248
conditions were so harsh

249
00:23:41,417 --> 00:23:44,887
that it was impossible
for a large animal to get enough to eat.

250
00:23:45,057 --> 00:23:48,288
All a bear can do then is to sit it out

251
00:23:48,457 --> 00:23:51,449
and try and conserve
as much energy as possible.

252
00:23:52,577 --> 00:23:56,172
To see how they cope with these
enormous seasonal changes,

253
00:23:56,337 --> 00:23:58,692
we must go back six months.

254
00:23:58,857 --> 00:24:02,645
In October, grizzly bears went into a deep sleep,

255
00:24:02,817 --> 00:24:04,808
their temperature dropped several degrees

256
00:24:04,977 --> 00:24:08,447
and their pulse rate decreased
to about ten beats a minute.

257
00:24:08,617 --> 00:24:12,974
They don't eat, drink or defecate,
but they do occasionally stir.

258
00:24:17,257 --> 00:24:22,206
During hibernation, a bear burns up
almost a million calories...

259
00:24:24,217 --> 00:24:27,448
virtually emptying its energy reserves.

260
00:24:39,057 --> 00:24:44,177
By spring, they will have lost
nearly a third of their bodyweight.

261
00:24:44,337 --> 00:24:48,933
To avoid starvation,
they must now find food - and quickly.

262
00:24:53,537 --> 00:24:57,689
Their diet will be driven
by a clearly defined seasonal cycle.

263
00:24:57,857 --> 00:25:00,212
Now, in April, they eat roots.

264
00:25:04,337 --> 00:25:06,407
Roots are followed by grass.

265
00:25:06,577 --> 00:25:10,126
It's easy food, but they'll
quickly move on to the next course

266
00:25:10,297 --> 00:25:12,333
if something really big shows up.

267
00:25:16,497 --> 00:25:19,455
This whale carcass could last them a month.

268
00:25:19,617 --> 00:25:23,212
And by May, fresh meat is on the menu.

269
00:26:01,017 --> 00:26:04,851
Mid-summer, and they're back on the salmon.

270
00:26:11,737 --> 00:26:16,174
This bear has been out of hibernation
for about four months.

271
00:26:16,337 --> 00:26:18,771
Surprisingly, it's not gained any weight.

272
00:26:18,937 --> 00:26:21,451
Indeed, it may even have lost weight.

273
00:26:21,617 --> 00:26:25,246
But if it's to survive the coming winter,
now is the time

274
00:26:25,417 --> 00:26:28,056
when it really has to pack on the pounds.

275
00:26:32,577 --> 00:26:36,331
Salmon, one of the most important
sources of food for bears,

276
00:26:36,497 --> 00:26:38,488
is now available in quantity,

277
00:26:38,657 --> 00:26:42,775
as the fish migrate in thousands
up the rivers to spawn.

278
00:27:15,617 --> 00:27:20,452
Chasing them uses a lot of energy,
but the rewards are great.

279
00:27:20,617 --> 00:27:23,370
Salmon are rich in protein and fat.

280
00:27:30,417 --> 00:27:35,730
So valuable is this source of food
that a bear that hasn't got a salmon of its own

281
00:27:35,897 --> 00:27:39,936
will spend considerable energy
trying to steal someone else's.

282
00:27:51,497 --> 00:27:55,615
In a good salmon year,
a bear can catch a dozen a day.

283
00:27:55,777 --> 00:27:59,213
This gives a huge boost to its energy reserves.

284
00:28:02,857 --> 00:28:05,815
But it's not just about numbers.

285
00:28:05,977 --> 00:28:09,174
Some parts of the fish
are more nourishing than others.

286
00:28:09,337 --> 00:28:14,775
If there are lots around, the grizzlies
will eat only brains and caviar.

287
00:28:16,097 --> 00:28:20,249
This behaviour piles on even more calories.

288
00:28:24,337 --> 00:28:26,851
Even when there are no salmon to be caught,

289
00:28:27,017 --> 00:28:30,214
bears can still find food out on these estuaries.

290
00:28:31,097 --> 00:28:35,932
Like pigs, they have
an extraordinary acute sense of smell,

291
00:28:36,097 --> 00:28:40,932
and that can guide them to food
even beneath the surface of the sand.

292
00:28:43,257 --> 00:28:45,009
Clams.

293
00:28:45,177 --> 00:28:50,126
How on earth can an animal
with massive paws and huge claws

294
00:28:50,297 --> 00:28:55,576
manage to open and extract meat
from a tiny shell like this?

295
00:28:57,417 --> 00:29:02,411
The answer is...with surprising dexterity.

296
00:29:04,577 --> 00:29:07,808
Clams may look small
in the paws of a grizzly bear,

297
00:29:07,977 --> 00:29:11,174
but they're still worth all that effort.

298
00:29:17,617 --> 00:29:21,815
Early autumn - two months to go
before hibernation,

299
00:29:21,977 --> 00:29:24,445
and the bear's appetite steps up a gear.

300
00:29:24,737 --> 00:29:27,729
A seasonal change in the bear's physiology

301
00:29:27,897 --> 00:29:31,685
now allows him to eat continuously
without ever feeling full,

302
00:29:31,857 --> 00:29:34,496
a huge advantage during the berry season.

303
00:29:34,937 --> 00:29:38,976
They may eat as many
as 200,000 berries a day.

304
00:29:39,137 --> 00:29:43,767
And that gives the next big boost
to a bear's energy reserves.

305
00:29:46,377 --> 00:29:50,450
But at this time of the year
they'll eat whatever they find.

306
00:30:23,257 --> 00:30:27,648
After three months of counting calories,
they're back in shape.

307
00:30:30,977 --> 00:30:36,654
For these grizzly bears in Alaska,
the real test is about to begin.

308
00:30:36,817 --> 00:30:40,890
With luck, they will have put on enough weight
to enable them to survive

309
00:30:41,057 --> 00:30:44,049
the coming five to six months of winter.

310
00:30:44,217 --> 00:30:50,929
They will only have done so
by being extremely unfussy feeders.

311
00:30:55,657 --> 00:30:58,933
The lifestyle of a generalist
may seem a good strategy,

312
00:30:59,097 --> 00:31:01,691
but from an evolutionary perspective,

313
00:31:01,857 --> 00:31:04,929
there's always the temptation to specialise.

314
00:31:06,937 --> 00:31:11,931
In India, there's another bear happy to tackle
anything remotely edible it comes across.

315
00:31:12,097 --> 00:31:15,294
But that is only for half the year.

316
00:31:15,457 --> 00:31:20,406
This bear, the sloth bear, has started
down the road to specialisation.

317
00:31:22,697 --> 00:31:27,407
Inside this mound of clay
lies a huge quantity of food,

318
00:31:27,577 --> 00:31:32,048
and the sloth bear has just
the right equipment to collect it.

319
00:31:37,977 --> 00:31:39,888
It has particularly large claws,

320
00:31:40,057 --> 00:31:43,129
perfect for breaking into
these sun-baked termite mounds.

321
00:31:43,297 --> 00:31:47,688
It's worth the effort, for just one colony
may contain a million individuals.

322
00:31:53,257 --> 00:31:56,454
The termites' first line
of defence has been broken.

323
00:31:56,697 --> 00:31:59,530
Faced with such a large
and destructive predator,

324
00:31:59,697 --> 00:32:03,736
there's little the soldier termites
can do to drive the bear away.

325
00:32:07,097 --> 00:32:12,012
As the termites swarm over their
smashed mound, the bear hoovers them up.

326
00:32:17,817 --> 00:32:23,096
But the greatest prize
are the larvae that lie inside the nest.

327
00:32:26,977 --> 00:32:30,447
The bear has other adaptations
as well as big claws.

328
00:32:30,617 --> 00:32:35,532
It's lost its two front teeth,
so by pursing its floppy lips into a tube,

329
00:32:35,697 --> 00:32:38,848
it can suck insects directly into its mouth.

330
00:32:39,017 --> 00:32:41,087
At the end of its snout, there's a flap

331
00:32:41,257 --> 00:32:45,455
that prevents dirt and dust
going up its nose at the same time.

332
00:32:49,537 --> 00:32:53,007
But the sloth bear may be heading for danger;

333
00:32:53,177 --> 00:32:56,772
the same danger that may
before long exterminate its cousin,

334
00:32:56,937 --> 00:32:58,893
the giant panda.

335
00:32:59,057 --> 00:33:03,096
For the moment, however,
there's no shortage of termites,

336
00:33:03,257 --> 00:33:06,772
and the sloth bear has still not become
as wholly reliant on them

337
00:33:06,937 --> 00:33:09,849
as the giant panda is on bamboo.

338
00:33:14,137 --> 00:33:18,176
Just as humans have had an impact
on the giant panda and its food,

339
00:33:18,337 --> 00:33:21,056
so they have on the sloth bear.

340
00:33:23,137 --> 00:33:25,605
In India, sloth bears live alongside people,

341
00:33:25,777 --> 00:33:28,052
and conflict between the two is common,

342
00:33:28,217 --> 00:33:31,334
resulting in hundreds of maulings every year.

343
00:33:36,537 --> 00:33:42,055
During the day, bears take refuge
in areas not used by people.

344
00:33:46,977 --> 00:33:50,606
Sloth bears may not compete
with cattle for food,

345
00:33:50,777 --> 00:33:55,248
but land turned to grazing
reduces the bears' termite harvest.

346
00:33:58,137 --> 00:34:00,128
Loss of natural habitat

347
00:34:00,297 --> 00:34:03,494
has had a serious impact
on wildlife across the globe,

348
00:34:03,657 --> 00:34:08,447
but, ironically, man-made habitats have
provided new opportunities for many omnivores.

349
00:34:20,057 --> 00:34:23,447
The modern city, a seemingly sterile world

350
00:34:23,617 --> 00:34:25,847
of concrete, steel and glass.

351
00:34:26,417 --> 00:34:31,537
It must be one of the most difficult places
for a wild animal to make a living in.

352
00:34:32,817 --> 00:34:38,096
It would be, if not for the extravagant
habits of the people who live here.

353
00:34:42,137 --> 00:34:46,449
The largest cities may contain
more than ten million human inhabitants.

354
00:34:46,617 --> 00:34:50,690
And where there are people,
there is food, lots of it.

355
00:34:51,937 --> 00:34:56,965
A city this size produces
around 10,000 tonnes of waste a day.

356
00:34:57,137 --> 00:35:00,334
If the residents are not to drown
in a morass of leftovers,

357
00:35:00,497 --> 00:35:04,536
it all needs to be cleaned up, continuously.

358
00:35:10,657 --> 00:35:14,889
Good hygiene is so important
in these crowded conditions

359
00:35:15,057 --> 00:35:19,096
that much time and money
is spent trying to sanitise our cities.

360
00:35:25,897 --> 00:35:29,014
But it isn't easy to wipe away
the evidence of food,

361
00:35:29,177 --> 00:35:31,054
not completely anyway.

362
00:35:31,217 --> 00:35:34,732
To an animal with an acute sense
of smell, food stands out.

363
00:35:34,897 --> 00:35:38,446
Everything else seems grey by comparison.

364
00:35:40,217 --> 00:35:44,495
We may not notice the scraps left behind,
but what's not taken away

365
00:35:44,657 --> 00:35:47,171
can become an opportunity for others.

366
00:35:50,297 --> 00:35:55,212
Under the partial cover of darkness,
a familiar face materialises.

367
00:35:58,337 --> 00:36:02,694
Racoons have found our cities
very much to their liking.

368
00:36:03,497 --> 00:36:06,933
Their great climbing skills
enable them to find shelter

369
00:36:07,097 --> 00:36:09,372
in roofs and chimney breasts during the day

370
00:36:09,537 --> 00:36:14,088
and also to move with ease in all parts
of this complex environment -

371
00:36:14,257 --> 00:36:17,772
a fact recorded by security cameras
every night of the year.

372
00:36:21,977 --> 00:36:24,491
(DOG BARKS)

373
00:36:25,497 --> 00:36:29,206
To find food,
racoons must descend to the ground.

374
00:36:33,737 --> 00:36:35,728
They're bold and intelligent animals

375
00:36:35,897 --> 00:36:40,015
and negotiate the dangers
of the road as confidently as humans.

376
00:36:42,057 --> 00:36:47,256
Indeed, city racoons are
significantly less likely to be hit by a car

377
00:36:47,417 --> 00:36:50,215
than their country cousins,
who get less experience

378
00:36:50,297 --> 00:36:52,606
of judging the speeds of vehicles.

379
00:37:02,497 --> 00:37:05,614
In an attempt to thwart garbage raiders,

380
00:37:05,777 --> 00:37:08,530
rubbish collection continues around the clock.

381
00:37:11,657 --> 00:37:16,094
But racoons are quick to take
advantage of any opportunities.

382
00:37:16,257 --> 00:37:19,010
If there's food around, they'll find it.

383
00:37:24,897 --> 00:37:29,368
The skills that made racoons
so successful in their original home

384
00:37:29,537 --> 00:37:32,688
also serve them well here, in the fast lane.

385
00:37:39,857 --> 00:37:44,169
The inquisitiveness they showed
when looking for food on the forest floor

386
00:37:44,337 --> 00:37:47,056
now leads them to rich pickings.

387
00:37:51,097 --> 00:37:56,217
The manual dexterity that enabled them
to capture crayfish in streams

388
00:37:56,377 --> 00:37:59,767
now leads them
to take off the lids of dustbins...

389
00:38:01,497 --> 00:38:05,695
and winkle morsels from jars, boxes and tins.

390
00:38:12,577 --> 00:38:16,536
Racoons are an American success story.

391
00:38:25,657 --> 00:38:29,855
They're one of the most successful
and widespread mammals on the continent.

392
00:38:36,497 --> 00:38:41,287
The biggest opportunists of all
have a slightly less subtle approach.

393
00:38:49,017 --> 00:38:53,249
Bears can break into cars
as easily as they can open clam shells.

394
00:38:53,657 --> 00:38:57,570
It takes more effort,
but the rewards can be huge.

395
00:39:05,857 --> 00:39:09,816
In Britain, the streets belong
to a different urban prowler -

396
00:39:09,977 --> 00:39:11,774
the red fox.

397
00:39:11,937 --> 00:39:17,489
Unlike racoons, foxes are territorial,
but they're also extremely adaptable.

398
00:39:17,657 --> 00:39:21,536
In a single year, a fox can change
from being totally rural

399
00:39:21,697 --> 00:39:25,849
to totally urban,
so foxes are always on the move.

400
00:39:38,417 --> 00:39:42,205
If I were to explore these city streets
for just a few hours,

401
00:39:42,377 --> 00:39:47,087
I'd almost certainly see more foxes
than I would in a whole year

402
00:39:47,257 --> 00:39:49,293
of walking in the countryside.

403
00:39:49,457 --> 00:39:54,292
Cities like this can support
ten times as many foxes

404
00:39:54,457 --> 00:39:56,607
as a similar area in the country.

405
00:39:57,577 --> 00:40:00,045
Foxes have one other thing going for them,

406
00:40:00,217 --> 00:40:03,527
at least here in Britain - their popularity.

407
00:40:03,697 --> 00:40:06,336
Surveys regularly show

408
00:40:06,497 --> 00:40:10,536
that the red fox is among
the nation's favourite mammals,

409
00:40:10,697 --> 00:40:13,370
a fact that foxes have been quick to exploit.

410
00:40:38,817 --> 00:40:42,332
Many of us encourage
our friendly neighbourhood foxes

411
00:40:42,497 --> 00:40:46,729
by putting out food,
and the foxes are only too glad to take it.

412
00:40:51,137 --> 00:40:54,413
comes from free handouts,
and the more food there is,

413
00:40:54,577 --> 00:40:56,568
the more foxes there are.

414
00:40:57,137 --> 00:41:00,413
However, there is another kind
of urban opportunist

415
00:41:00,577 --> 00:41:03,171
that is much more successful
than the red fox.

416
00:41:03,337 --> 00:41:07,125
But it's at the opposite end
of the popularity scale.

417
00:41:07,737 --> 00:41:12,970
We don't encourage it in any way,
and yet it thrives on our leftovers.

418
00:41:13,137 --> 00:41:15,526
If statistics are anything to go by,

419
00:41:15,697 --> 00:41:19,656
you are within five metres of one at all times.

420
00:41:19,817 --> 00:41:23,856
There's probably one
directly beneath me as I speak.

421
00:41:38,217 --> 00:41:42,369
Warm water emptying from baths
and washing machines

422
00:41:42,537 --> 00:41:45,688
and sluicing into the network
of sewers beneath our homes

423
00:41:45,857 --> 00:41:50,487
creates a surprisingly stable
and temperate environment.

424
00:41:50,977 --> 00:41:56,097
It's an ideal habitat for one of the most
widespread and adaptable mammals -

425
00:41:56,257 --> 00:41:58,248
the brown rat.

426
00:41:59,897 --> 00:42:03,253
It's not just the steady temperature
that the rats like.

427
00:42:03,417 --> 00:42:06,329
There's a steady supply of food as well.

428
00:42:08,537 --> 00:42:13,736
Scraps flushed down the sewers
enable a rat to spend its entire life here,

429
00:42:13,897 --> 00:42:16,013
though, contrary to popular belief,

430
00:42:16,177 --> 00:42:19,374
there's not enough food
to support swarms of rats.

431
00:42:27,497 --> 00:42:32,093
The only thing they need worry about
is a sudden rise of water level.

432
00:42:32,257 --> 00:42:37,490
Sewer rats are particularly sensitised
to this, often with good reason.

433
00:42:43,577 --> 00:42:46,614
Her nest is in danger of flooding,

434
00:42:46,777 --> 00:42:50,292
but fortunately she knows
a safer place to take her babies.

435
00:43:27,537 --> 00:43:30,176
They're guided very largely by smell,

436
00:43:30,337 --> 00:43:34,888
and follow tried and tested routes
that they know to be safe.

437
00:43:41,337 --> 00:43:45,967
Moving six youngsters under such conditions
seems a hard task,

438
00:43:46,137 --> 00:43:48,287
but rats are resilient creatures,

439
00:43:48,497 --> 00:43:53,366
a characteristic that makes them suited
to living in these unnatural surroundings.

440
00:44:04,697 --> 00:44:09,407
In spite of their numbers,
we seldom see rats out and about.

441
00:44:09,577 --> 00:44:14,856
But we all know they're there,
eating our food and probably spreading disease,

442
00:44:15,017 --> 00:44:18,054
so we wage war on them with traps and poison.

443
00:44:18,217 --> 00:44:23,052
What happens when rats are allowed
to live unchecked in a human society?

444
00:44:25,697 --> 00:44:28,973
(BELLS, DRUMS AND CHANTING)

445
00:44:44,977 --> 00:44:49,687
In this temple in northern India, rats are sacred.

446
00:44:49,857 --> 00:44:55,170
Local people believe that after death
they return to Earth as rats,

447
00:44:55,337 --> 00:45:00,491
so rats here are fed and protected
and, indeed, worshipped.

448
00:45:00,657 --> 00:45:05,173
This is not just a rat haven, it is a rat heaven,

449
00:45:05,337 --> 00:45:08,090
and the rats take full advantage of it.

450
00:45:29,497 --> 00:45:34,173
In the wild, rats are nocturnal, but not here.

451
00:45:38,937 --> 00:45:42,896
These rats don't shun the daylight like city rats.

452
00:45:43,057 --> 00:45:45,855
Why should they?
There's nothing to harm them here

453
00:45:46,017 --> 00:45:50,932
and plenty of food, and, as a result,
they swarm in great numbers.

454
00:45:54,097 --> 00:45:58,295
Colonies in the wild,
which grow to be about 600-strong,

455
00:45:58,457 --> 00:46:01,051
normally then break down and divide,

456
00:46:01,337 --> 00:46:06,092
but here their population
has stabilised at around 6,000.

457
00:46:11,057 --> 00:46:15,847
The size of the world-wide
population of rats is incalculable.

458
00:46:16,017 --> 00:46:19,214
Their boundless opportunism
means that today they inhabit

459
00:46:19,377 --> 00:46:22,926
every continent on Earth, including Antarctica.

460
00:46:23,257 --> 00:46:26,454
Could there be a more successful mammal?

461
00:46:36,937 --> 00:46:41,647
Well, yes...us, the human species.

462
00:46:41,817 --> 00:46:44,854
We are the ultimate demonstration

463
00:46:45,017 --> 00:46:48,214
of just how successful a mammal can be

464
00:46:48,377 --> 00:46:51,528
that is prepared to eat pretty well anything.

465
00:46:53,617 --> 00:46:56,529
This is the Kumbh Mela,

466
00:46:56,697 --> 00:47:02,294
a spectacular Hindu festival in central India
attended by millions of people.

467
00:47:02,457 --> 00:47:05,688
It's the largest gathering
of people for a common cause

468
00:47:05,857 --> 00:47:08,735
ever seen in the history of the world.

469
00:47:10,377 --> 00:47:14,768
Over two weeks, this temporary city
on the banks of the Ganges

470
00:47:14,937 --> 00:47:19,294
will shelter a staggering
one hundred million people.

471
00:47:19,457 --> 00:47:22,927
Since they're Hindus,
most are strictly vegetarian,

472
00:47:23,097 --> 00:47:27,409
but across the world we seem to be able
to thrive whatever the diet;

473
00:47:27,577 --> 00:47:31,934
whether it be one dominated
by lentils and rice or by hamburgers.

474
00:47:35,377 --> 00:47:39,655
We have learned how to create
our own food resources,

475
00:47:39,817 --> 00:47:42,377
so our population is no longer limited

476
00:47:42,537 --> 00:47:45,609
by the quantity of food that occurs naturally.

477
00:47:47,177 --> 00:47:51,773
That development enabled us
first to dominate the Earth

478
00:47:51,937 --> 00:47:54,610
and eventually to overrun it.

479
00:47:54,777 --> 00:47:59,532
An essential key to our success
has been the one that we share

480
00:47:59,697 --> 00:48:05,533
with rats and racoons, bears and foxes -
an adaptable nature

481
00:48:05,697 --> 00:48:10,293
and an ability to seize
an opportunity when we see it.

482
00:48:10,457 --> 00:48:15,008
You might say that it's not the meek
that have inherited the Earth,

483
00:48:15,177 --> 00:48:17,645
but the opportunists.