The Ark Files - The rainforest

On each side of the equator, 20 degrees to the north and south, are the world's tropical rainforests. This is where you find the greatest amount of heat, light and moisture - and an amazing diversity of life.

The High Life

Most creatures live in the rainforest canopies where light is abundant. Gangs of monkeys and apes, flocks of birds and hordes of fruit bats gather to feast on ripe avocados, durian and jackfruit. These animals will then help the trees by spreading their seeds far and wide. The flowers up here are brightly coloured and laden with nectar to attract the equally colourful butterflies and birds for pollination. Some are pale and smelly to entice night-flying bats.

Eagle eyries

Some trees poke their heads above the tangled tops and these are the nesting places of the Crested Hunting Eagles. Although large, they have rather short, broad wings and long tails. This lets them chase monkeys and birds through the thick jungle, swerving and dodging like fighter planes in a dog fight. The eagles then carry the struggling prey back to their nests to tear it apart and eat it, bit by bit.

Cat acrobats

Tree-living cats, such as the Clouded Leopard, have superb reflexes and perform amazing gymnastic feats in hot pursuit of squirrels and monkeys. The leopards race up tree trunks, leap across branches and can hang from their hind legs, even saving themselves from a fatal fall by catching hold of a branch with one paw.

Mayhem In The Middle

Beneath the teeming canopies there is less light but still lots going on. Lianas loop themselves through the branches and tree trunks. These thick vines provide transport for many animals including the largest of tree dwellers, the orangutan. Orangutans swing their huge shaggy bodies, often burdened with heavy babies, along these vines, using them as rope ladders to move from tree to ground level and back up again.Ever available inch of space is used, with orchids, ferns and bromeliads decorating the tree trunks. Bromeliads collect pools of rainwater in their leaves, creating micro-ponds for frogs to deposit their eggs and provide homes for tadpoles.

Strangler figs

Not all plants are user friendly. Take the Strangler Fig. Its seeds germinate in the compost which collects on the boughs of trees. As the fig grows, its roots reach down to dig into the soil at the tree’s base. Then it begins to grow rapidly, wrapping more roots around the tree trunk and producing its own crown of leaves that begins to overshadow the host tree. Eventually, and it may take up to a hundred years, the original tree dies and decays leaving a hollow, standing cylinder of living Strangler Fig to take its place in the jungle.

Heads up!

Some animals that normally travel along the ground have taken to the air to avoid the dense tangle of roots and buttresses. Frogs and lizards glide and even a species of snake has become airborne. The gliding frog has very long toes with webbing in between. When it jumps from a tree, its toes spread out and lock into place and the webbing can then trap the air and act as a parachute. It can then glide up to 45 metres. The 'flying' snake speeds along a branch before launching itself into the air. It then flattens its thin body to glide through the jungle like a falling streamer, much to the dismay of anyone happening to look up.

Completely Floored

The forest floor is a world of low light and high humidity – but it is not a wasteland. Fallen nuts and fruits and underground roots and tubers provide easy meals for mouse deer, royal antelope and agoutis. These animals are perfectly adapted for foraging on the forest floor. The size of a large rabbit, with the slenderest of legs ending in sharp claws or hooves, they seem to run on tiptoe. And they are highly alert, able to freeze in an instant before zigzagging away.

Seize the daylight

Trees fall all the time in rainforests, leaving gaps which are quickly filled by other plants. Wild yams take advantage of the extra space and light, growing an astonishing three metres in a day. Wild yams also increase their chance of survival by producing nectar that attracts ants, which in turn protect the growing plant by defending it from predators.

Elephant corridors

The elephants of the African rainforest are paler and smaller than their savannah cousins and are enthusiastic fruit eaters. One particular fruit weighs two kilos when ripe and falls to the ground with a resounding thud that can be heard from quite a distance by alert elephants. Smelling strongly and irresistibly of garlic, the skin is, however, extremely tough. But the elephants have learned to kneel and use their tusks to spear and prise the fruit open. They also keep a mental map of the locations of these trees and follow trails that they have carved out of the jungle to locate them at fruiting time.