Japan

Isolated from the Asian mainland, Japan’s animals have been forced to evolve strategies to survive most violently active islands on earth in a climate of extremes. 

Produced by NHNZ

The islands of Japan sit above the intersection of four of the most active tectonic plates on the planet. Earthquakes and volcanic eruptions are frequent. This geological turbulence has created one of the most fascinating evolutionary histories on Earth. Japan has been connected to mainland Asia several times in the past, allowing for new invasions of species…but each time the land became isolated again and the forces of evolution took over.

A troop of macaque monkeys trudge through deep mountain snow. At an alpine spa, they lower themselves into warm thermal pools. These monkeys are relative newcomers to Japan, evolving in the tropics. So what are they now doing in the snow? Only one other primate survives so far north – humans. We learned how to adapt to the cold and so have these macaques. They have changed their diet, shape, size and behaviour in the half million years since they came here… but have they adapted enough to be considered a new species?

A cast of bizarre ancient species have existed here much longer…since the islands broke from the Asian mainland. They are Japan’s ‘originals’, mysterious and unique survivors…

A menacing troll, the Giant Salamander, stalks mountain rivers, attacking fish with speed and ferocity. A mother Amami rabbit buries her babies alive to hide them from a heat detecting pit viper. An insect called the Giant Water Bug snatches a mating frog off an overhanging branch and drags it down to the depths, injectint salivary enzymes and sucks up the body ‘soup’.

Many of Japan’s hundreds of islands are very small. Animals cast away on these outcrops must find innovative ways to overcome periods of starvation. Natural selection has pushed them to become either generalists or specialists in their diet…

A cat on Iriomote Island has become a generalist, a hunter with the greatest range of prey of any cat in the world; from guppies to grasshoppers, crabs to berries. Conversely, the highly specialized jaw of Iwasaki’s slug snake spirals to the left, and only eats snails with left-handed spiral shells.

How does this strange collection of old and new animals overcome the extremes of an ice age, earthquake, volcanism, rain and starvation? The islands of Japan are a hothouse of the bizarre…the inhabitants’ mutations being honed in tandem with the evolution of the land they live on.

Episodes From This Series

Borneo

48 minutes / 2014

Japan

50 minutes / 2010

Brazil’s Cerrado

50 minutes / 2010

Australia

50 minutes / 2010

New Zealand

50 minutes / 2010

Costa Rica

48 minutes / 2014

Africa’s Albertine Rift

1 hour / 2014

China – Roof of the World

1 hour / 2014

Western Ghats and Sri Lanka

1 hour / 2014

The Arid Namib

1 hour / 2014

Madagascar

1 hour / 2010

Africa’s Rift Valley lakes

1 hour / 2010