Wild Asia: A Forest for All Seasons

In the warming sun of late spring,

a mother rests after giving birth.

Her new daughter is only six hours old

But their rest will be brief,

for they belong to a troop of the northernmost monkeys on earth,

always on the move through the temperate forest that is their home.

Both the lives of the macaques and the trees that they live with are ruled

by the timing and the changing of the seasons of the temperate world.

Much of Asia is covered by the temperate forests that stretch

from the foothills of the Himalaya to the islands of Japan.

These forests lie in a broad band between the frozen wastes of the arctic

and the humid tropical forests far to the south.

There are two kinds of

temperate forests - those that remain evergreen,

and the deciduous forests, where the changing seasons are clearly seen.

As the earth swings closer to the sun, and then away again,

the plants and the animals of the temperate forests

are exposed to all the climate’s extremes.

Long ago, when much of the world was frozen in the winter

of the last ice age, many trees became extinct.

But some of eastern Asia escaped this ice,

and there the temperate forests

now contain a greater number of tree species

than in the rest of the continent.

In Japan these forests still cover vast areas of her mountains.

Forests of Cherry and Maple,

of Oak and Beech are driven by the seasons,

and trees must evolve strategies for survival.

In northern Japan, Beech trees dominate the forest.

They’ve evolved a strategy of living long,

growing taller than the other trees,

and reacting quickly to the lengthening days of spring.

Beech trees are amongst the earliest to bud...

amongst the first to flower, to be pollinated by the wind...

and the first to send out leaves to claim

the energy-giving light before it reaches the forest floor.

But rather than trying to compete for light against the taller trees,

one extraordinary plant steals a march on the rest

of the forest by following a timetable of its own.

The few Japanese who know this plant call it “naniwazu”.

Instead of shedding its leaves in autumn, “naniwazu” keeps them green.

They’re ready, as soon as spring comes,

to take in sunlight while the canopy overhead is still open.

Its precocious flowers attract the first pollen-bearing insects of the season.

By breaking the rules of the seasons,

“naniwazu” knows its own summer

while other plants have just begun to grow their spring leaves.

For the forest birds, it will soon be time to breed.

A female Great-spotted Woodpecker searches for insects that have,

throughout winter, sheltered under the bark.

Spring reveals a myriad of strategies to deal with the changing seasons.

A tiny caterpillar climbs up

from the leaf litter where it hibernated over winter.

But the colours that were a perfect camouflage in autumn

will soon be dangerously conspicuous,

for the caterpillar is climbing back into a changing world.

To survive, the caterpillar must follow suit.

Responding, like the forest,

to the lengthening hours of daylight and the rising temperature,

it sheds the skin that looks like a dead leaf

and assumes the colours of a spring leaf.

The caterpillar mimics the leaves on which it will keep feeding

until it undergoes its final transformation

into a butterfly of summer.

All through the forest trees are exploding into flower.

After the long winter months,

spring is a time when Japanese Macaques make the most of forest’s bounty.

Macaques are perhaps the most adaptable of all monkeys.

They colonized many parts of Asia from the tropics

to the temperate forests adapting and changing as they went,

they first arrived in Japan perhaps half a million years ago.

Japanese macaques live in troops and move within a defined territory.

There are thirty-five animals in this troop,

made up of a handful of males and two family groups of related females,

each lead by an older matriarch.

This female is about twenty-six years old.

Her knowledge of the forest has been vital,

not only for her immediate family, but for the troop as a whole.

Japanese macaques are different from other macaques.

They’re less-inclined to squabble

than their cousins who live in tropical forests.

These macaques are mainly vegetarian,

but edible plants are widely scattered throughout the forest.

To get enough to eat the troop must continually move through its territory.

What’s even more unusual, is the degree of tolerance between the male macaques.

“Ito”, at sixteen years old,

is unchallenged as the senior male of the troop

even though he lost one of his legs in a trap when he was young.

He usually stays on the fringes of the family groups, constantly watching.

The family group is the very heart of Macaque society

and once a female is born into group, she will never leave.

Young males however will leave when they are around five years old.

They will roam the forest either living a solitary life

or in small bachelor groups,

before attempting to join another troop with females.

In this troop as well as “Ito”, there are two other big males.

“Gonzui” is fifteen.

Like “Ito” he never takes his eyes of the females.

And on the very fringes of the troop is another male

who has recently joined the group.

Only eleven years old,

he always keeps his distance but is a member of the troop,

accepted within their territory.

The ancestors of these Macaques arrived in Japan’s far north

at the end of the most recent Ice Age.

As the earth warmed,

macaques moved further and further north into new territories.

The northern shores of Japan’s main island of Honshu

are as far north as any Macaque can go.

They will not return to the south since their territory adjoins

that of other Macaque troops.

These northernmost monkeys on earth have had no choice

but to adapt to the seasonal extremes of the temperate forest where they live.

Spring comes late to the north of Japan.

It was at the end of May when the new baby female was born.

She’s now three days old and is in safe hands.

Macaques give birth only to a single infant at a time.

A mother couldn’t carry or care for more than one.

Babies are born at the time

that gives them the best chance of growing strong

and independent before winter, for then there would be little food

and a mother would be unable to produce enough milk to keep an infant alive.

In the gentle spring sun,

the baby explores the warm world that is her mother.

She starts to make out the light and shade of the forest.

She has been born with a strong instinct to grasp and strong hands to do so.

For almost from the moment of birth

she must be able to cling to her mother as she moves

through the forest with the rest of her troop.

As the females move on,

sometimes calling softly to each other “Ito” follows.

He may be the oldest male, but he’s not the leader of the troop,

in fact they have no leader.

The forest too is moving.

The days are longer, and the canopy is full,

filtering out much of the light from the forest floor.

So for the out-of-step “naniwazu”, it’s time to shut down.

Unable to win the race for the light,

it begins to discard its leaves in an autumn of its own.

But the rest of forest is reacting to the sun

that is rising ever higher in the sky.

On the rich spring leaves of a Hackberry tree

the caterpillar that emerged

from the leaf litter has grown large and plump.

Triggered by a combination of the rising temperature

and its own internal body clock,

it nears the end of one phase of its life

and begins to discard a skin it will no longer need.

It will never again feed on leaves

so it drops the head and mouthparts it no longer needs.

Inside the hardened outer case of the pupa,

the body will undergo an amazing transformation,

the timing of which is crucial...

for when it emerges as a butterfly

it favours tree sap which is at its most abundant in summer.

It still remains aware of the outside world,

and is ready to respond to it.

A single ant is hardly a threat, but a swarm might be.

The nervous reaction is enough to startle almost any predator.

After two weeks a butterfly emerges

it’s a female.

The males have already appeared and established their territories.

She rids herself of excess moisture in her body,

then rests for a few hours to let her wings dry,

and she’s ready to find a mate in the summer forest.

Almost imperceptibly the forest too is changing.

The green of summer is darker than in spring.

There are frequent summer rains,

the days are long and warm and food is abundant for the macaques.

With the birth of four babies, three of them males,

there are now thirty nine animals in the troop.

Prompted by the warmth of the summer days,

these northern Macaques start to molt their winter coats.

Each individual is different,

some hardly molt at all while others

like the twenty-six year-old matriarch are losing

almost all their winter coats.

“Ito” has shed his thick winter fur.

Because he seldom mixes with the family groups,

when he needs a scratch he has to do it himself.

Within the family groups, the related females groom each other.

Grooming is the activity which is at the very bedrock of macaque society.

This constant and tender loving care forms bonds

and alliances between individuals that will last a lifetime.

While still producing milk some nursing mothers

hardly molt their winter coats at all -

and having thick fur gives a baby more to cling to.

In northern Japan summer is short.

These northern-most monkeys on earth are best adapted to the season

which will last the longest, the harsh winter months that lie ahead.

It’s now late June, the babies are almost a month old.

As their mothers rest, they begin to explore their forest world.

But the last to be born, a baby boy,

is still not keen to stray from his mother.

The baby girl, the first born, is more adventurous.

She’s already climbing up into the forest.

It’s a new world, full of wonders.

Even at this age they learn to watch and listen to

other members of their family group.

And just like any child in summer, if there’s a stream handy,