Species are both dependent
and compete with each other, which leads to a fragile equilibrium.
The incredible biodiversity of the rainforest renders the equilibrium
The basic idea is that each specie, however modest, has its importance
in the general equilibrium and represents just one link in an immense
Example : pollinization
Most flowering plants of these regions totally depend on insects,
birds and bats for their survival : the rainforest's density renders
wind pollinization inefficient, except perhaps for the very large
Another example : that of the
atta type leaf-cutting ants (more than 200 species). They live in
colonies of up to 5 million individuals. They cut the leaves of
certain trees (not all
) and bring them under the earth. They
"cultivate" on these leaves a mushroom on which they feed.
This mushroom does not exist elsewhere in nature. It can digest
the leaf cellulose, something the ants are incapable of doing. The
ant cannot exist without this mushroom, which does not exist without
(A large tree, "hymenaea courbaril", has developed an
original protection to prevent the atta ant from denuding if of
its leaves : it contains elements which are toxic not for the ant
but for the mushroom !). The ecological impact of the attas is considerable.
They manage to form true 20 cm large "highways" on the
ground. Studies have shown that they consume by themselves as much
foliage as all the herbivorous vertebrates of the rainforest.
Last example even more fascinating
: Another specie of ants, pseudomyrmex ferruginea, lives on certain
acacias. They systematically attack any "visitor" (insect
or human hand). But they also cut with their mandibles plants that
start to grow on or above the tree and which might hinder its growth.
As a counter part, the acacia has developed cavities to shelter
ants and also secretes a nectar to feed them !
AND MIMICRY PHENOMENA
Nearly every specie has its
predator and each one has developed means of defense against them.
Before fight or violent confrontation, one of the principal means
of defense is to become undetectable. That is why you have the impression
that the forest is empty.
The mimicry phenomena are fascinating :
. Certain species disguise themselves to escape from predators (defense
. Others try to become undetectable by their eventual prey (offensive
. Often both kinds of mimicry are found in the same specie
A perfect example of defense
mimicry is found in the phasms, these insects look exactly like
Mimicry is never absolute,
it is always relative to the surrounding environment of the animal
or to certain of its elements. The coat of jaguar for example: its
black-spotted yellow looks garish against the cement of the Zoo
on which the animal rests. But believe me, in the forest, the camouflage
is very efficient. Most territorial animals of the rainforest are
nearly undetectable IF THEY ARE NOT MOVING.
How have they become so adapted
to their surrounding environment?
This is what the THEORY OF THE EVOLUTION
OF THE SPECIES, developed in the second half of the 19th Century by Charles
Darwin and Alfred Russel Wallace, tries to explain. Both stayed for a long
time in the Amazon zone and found there many sources of inspiration.
Schematically, within a specie, certain individuals have certain characteristics
that make them more apt to survive than others in a similar environment:
for example, the darker an animal is, the less detectable will it be against
a dark background.
From then on, the darker individuals have an advantage
susceptible of being seen by predators, their number will tend to increase
proportionately and the "dark" gene will become progressively
This evolution occurs sometimes "relatively" fast. One of the
best known cases is that of a butterfly. Following the 19th Century industrial
revolution and the smoke it generated, some specimen of this specie, originally
light grey, have become nearly black!
In Amazonia, this adaptation can be totally fascinating:
For example, an extraordinary
case of offensive mimicry: certain small spiders feed exclusively
Their body has evolved to strikingly resemble the body of one of
The cephalothorax (the characteristic thorax/head unit of arachnidae)
has divided itself in order to make believe there is a head.
The first pair of legs has lost its ambulatory function to simulate
a pair of antenna.
Thus these spiders can become undetectable by ants.
Other cases, this time of defensive mimicry, concern many harmless animals
imitating aggressive or poisonous species.
Certain butterflies resemble wasps so much that you cannot tell them apart.
Certain grass snakes imitate perfectly the spectacular skin of a very poisonous
coral snake specie.
These examples are relatively simple.
The mimicry phenomena can be much more complex in their relation to the
A study on the butterflies of Peru has shown that a specific colour of wings
corresponds to different strata of the great rainforest:
From ground level up to 2m high : the "transparent" zone : transparent
wings with black streaks.
From 2 to 7m high : the "tiger" zone : wings streaked with yellow,
brown, black and red.
From 7 to 13m high: the "red" zone: red is the dominant wing colour.
From 15 to 30m high: the "blue" zone.
From 30m to the canopy: the "orange" zone.
These are the dominant tendencies,
of course, and it does not mean that no blue butterflies will be found near
the ground! But the hypothesis being defended is that each "complex"
or "colour" corresponds to the best camouflage of the butterfly
when it flies, according to light conditions in the different forest strata.
More rarely, instead of mimicry, certain species "choose" to deliberately
attract attention by loud colours, generally based on yellow, orange and
red, to warn the predator of the danger they represent in case of attack.
These are generally poisonous or venomous species. In this case, it calls
upon the genetic memory of the aggressor.
Two splendid examples:
coral snakes (micrurus sp)
dendrobate frogs (their skin secrete an extremely active venom).
Unfortunately for the amateur photographer, coral snakes and dendrobates
are shy creatures, they hide most of the time in the humid ground cover
of the forest or under dead wood.
Finally, certain batrachians, reptiles
or insects show "flash" colours, with the aim of "blinding"
or momentarily impressing an aggressor thus giving them time to flee. "Agalychinis
Callydrias", a small tree-climbing frog of Central America has for
example large brilliant red eyes. It stays usually on leaves with closed
eyes. When it opens them, the effect is surprising!!
As a conclusion on mimicry, there are
Take for example the case of
the large macaw, linked to the parrots:
They are large and highly coloured.
They belong to the rare loud animals of the great rainforest. I
will even say VERY loud!
These animals make no effort to hide, I therefore thought that they
had no predator. How wrong! I once saw a great harpy eagle "murder"
one of these birds.
All this is fascinating, you will tell me, but a little discouraging.
Is there no chance of seeing wild animals in the rainforest?
There is, of course but YOU HAVE TO PUT ALL LUCK ON YOUR SIDE BY
LEARNING TO BEHAVE ADEQUATELY IN THE SURROUNDING ENVIRONMENT.
You know now that a walk through the forest is no safari. Any passive
attitude will be sanctioned by failure. You have to stay concentrated,
make great efforts of attention
First of all, there are AUSPICIOUS HOURS, and those that are not.
At the height of the heat, animals limit their moving about. Prefer
the morning or the end of afternoon.
Birdwatchers know it, it is
necessary to get up early.
Learn to use all your senses, in particular
hearing and smelling. As has been shown, it is rare to localize an animal
LISTENING IS FUNDAMENTAL :
First of all, some species, very hard
to see at first sight, can be localized by their cry. I have spoken of the
macaws, in fact, the discordant cries of all parrots can be heard from rather
The shrill whistling of the large toucans is easily recognizable.
A small bird, the screaming
piha (lipaugus vociferans) has what might be called a very characteristic
song (!) that you will hear very often
the males spend three
quarter of their time calling the females.
One of the most characteristic
sounds of the great rainforest is the cry of the howler monkey (alouatta
sp) : it is somewhat similar to the sound of the wind during a raging
These howls can be heard kilometres away and are very impressive
when close by.
They are due to a sort of goitre that these monkeys have and which
serves as resonance chamber.
Among insects, the sound of innumerable cicadae can be deafening
night, the batrachians take their turn, certain species can prevent you
from sleeping : one day, I camped under a large tree in the south of Venezuela.
Shortly after sundown, a true concert of tree-climbing frogs started above
The Ye'Kwana Indian chief who accompanied me got up from his hammock, requisitioned
a young Indian and showed him the tree. The next morning, the boy proudly
showed us the culprits : he had not killed them but had captured them and
had carefully tied them together with fine lianas. The chief ordered him
to liberate them
This small anecdote gives you an idea of the psychology
of the Indians, a subject that I will treat later.
All these are sounds that hardly go unnoticed.
In most cases, you will have to listen carefully to hear the slightest sound
The slightest rustle of dead leaves can mean a reptile on the ground, a
creak above you, a monkey in a tree.
The other senses
THE USE OF SMELLING IS ALSO FUNDAMENTAL
Some species smell strongly, either
directly like the wild pigs, or indirectly through their urine, like the
howler monkeys and the felines that mark their territory like this.
The only time I encountered a giant
armadillo (priondontes maximus), a rare nocturnal specie that can attain
60kg, I mostly heard him dragging himself along dry leaves and I smelt him!
The animal really stank!
No need to open your eyes wide
to look at what passes as a horizon, your chance of directly seeing
an animal is just about nil, but try to notice traces. When I speak
of traces, I don't mean only tracks on the ground, but also the
secondary manifestations of animal presence :
The foliage which moves a few meters ahead of you.
Branches that move in a tree in front. That is why it is simpler
to see monkeys if there is no wind
Similarly, if you pass through
a place littered with fruit, look carefully in the trees and around
you, there is a strong chance that a fruit-eating animal, mammal
or bird, is hiding nearby.
As a corollary, during hikes :
Don't speak continuously
to your guide. It is he who, most of the time, will spot the animals
that you will see. If he has to turn around every 30 seconds or
so, he will not be able to do his work correctly. Needless to say
that if you spot, hear or smell something interesting, you must
share it with your group, but keep questions of general interest
for later, if need be, write them in as small notebook.
Walks in the forest are usually done on narrow trails, single file.
Your guide must be at the head, for it is he who is most apt to
spot a snake coiled up on the trail.
Don't stay too close so as not to hamper him, especially if he has
to use his machete often, but don't stay too far either. Seeing
an animal is generally furtive, a few seconds or less (I am not
speaking of invertebrates).
If you are too
far, you will be told "I just saw an agouti, but he escaped
quickly" or "you just missed a group of spider monkeys"
and other frustrating remarks because you will not have seen anything.
If there are many of you, organize
rotations in order not to have always the same one be behind the
Be patient, don't get discouraged, try to remain in a state of concentration,
even if the walk is long. I remember guiding a hike that lasted
three days during which we saw nothing. The last evening, I offered
a night walk. During two hours, we saw nothing. Coming back to the
place where we had left our dug-out canoe, I found myself face to
face with a superb puma, not intimidated at all. I made desperate
signs towards the rear to try to attract the attention of my companions
but they were at least 50m away, in the process, I presume, of telling
each other about their last beach week-end. When they arrived at
last, the animal had of course disappeared!
My personal experience has
shown me that, in a group, it is always the same ones who see something,
and always the same ones who see nothing!
Remember however that even with the best intentions in the world,
the chance factor is important and the fact of having purchased
an organized tour does not give you a guarantee of meeting animals.
The rainforest is mostly an atmosphere. It is in the Zoo that you
will see the animals best from close!