|
|
Tropical Rainforest:
Animals
There
are billions of species of mammals, insects, birds and reptiles
found in tropical rainforests. There are so many that there are
millions that have not been named or even identified yet.
A tree kangaroo found in tropical rainforests
of Papua New Guinea
About half of all the world's animal species live in tropical rainforests, in all the layers of the forest.
It is estimated
that there are more than 50 million different kinds of insects
alone in tropical rainforests. Almost 50 different species of
ant were found on one tree in Peru.
Tropical rainforests are almost perfect for animal survival. It
is always warm, and there are no season changes bringing times
of little food. There is shade from the heat and shelter from
the rain. There is no shortage of water.
Tropical Rainforest:
Animal Adaptations
Because there are so many creatures living in the rainforest,
there is a great deal of competition for food, sunlight and space.
Some animals became
very specialised. This means that they adapted to eating
a specific plant or animal that few others eat. For example, parrots
and toucans eat nuts, and developed big strong beaks to
crack open the tough shells. 
Leafcutter ants climb tall trees
and cut small pieces of leaves which they carry back to their
nest.The leaf pieces are about 50 times their weight.The ants
bury the leaf pieces, and the combination of the leaves and the
ants' saliva encourages the growth of a fungus, which is the only
food these ants eat.
Sometimes there are relationships between animals and plants that benefit both. Some trees depend on animals to spread the seeds of their fruit to distant parts of the forest. Birds and mammals eat the fruits, and travel some distance before the seeds pass through their digestive systems in another part of the forest.
One problem with specialisation is that
if one species becomes extinct, the other is in danger too unless
it can adapt in time. The dodo, a flightless bird of Mauritius,
became extinct in 1681. Today there are just 13 calvaria
trees left on the island, each over 300 years old, and nearly
at the end of their life. Scientists realised that the seeds had
to pass through a dodo's digestive system before they could germinate.
It seemed that the tree species would also become extinct, but
scientists tried domestic turkeys and have successfully managed
to germinate some seeds.
Many
rainforest animals use camouflage to 'disappear' in the rainforest.
Stick insects are perfect examples of this. There are some
butterflies whose wings look like leaves. Camouflage is of course
useful for predators too, so that they can catch prey that hasn't
seen them. The Boa Constrictor is an example of a camouflaged
predator.
The South American three-toed sloth uses camouflage and amazing slowness to escape predators. Green algae grows in the sloth's fur, which helps camouflage it in the forest canopy. Sloths are among the slowest moving animals of all (inside too, as it takes about a month to digest food). They hang from branches in the canopy, and are so still that predators such as jaguars don't see them.
Some animals are
poisonous, and use bright 
colors to warn predators to leave them
alone. There are several species of brightly colored poison
arrow frogs. Native Central and South American tribes used
to wipe the ends of their arrows onto the frog's skin to make
their arrows deadly poisonous.
Click
here to
find out more about some rainforest animals
|
Temperate rainforests |
| Back to Biomes main page | Back to Planet Earth |
