Lemurs, Monkeys and Apes - not all on the same evolutionary tree
In this article I want to propose a new idea: that apes are not directly related
to monkeys or prosimians, and similarities in their form are merely features of evolutionary
convergence. Instead, I will describe a new pathway for rainforest ape evolution;
this idea was first conceived as a result of comparing brain morphology. That research
suggested a possible route of rainforest apes evolution from a predatory canid (African
hunting dog). This notion may seem preposterous at first, if not insulting to the
ego, but I believe this line of evolution is demonstrated by similarities in brain
architecture between apes and canids.
Brain architecture follows a linear evolutionary pathway which involves incrementally
added faculties. By contrast, other organs like skeletal structures and dentition
can change their form profoundly over short periods of time. For this reason, much
of the early classification of animals is likely to be erroneous. In the light of
a new appreciation of the process of reversion, animals can switch aspects of their
form quite dramatically. Consequently, I believe, no longer should animals be classified
in groups by similarities as say, the number of toes, the type of dentition, or the
way they move about in trees.
Predatory hunting dogs have roamed the savannahs of Africa for at least 30 million
years. These animals were perhaps the forerunners of a very successful family of
mammals - the Canidae which nowadays includes wolves, jackals, foxes and dingos,
to mention a few.
Predatory animals, generally, are much more intelligent as individuals than their
grazing or scavenging equivalents, because successful hunting demands group coordination
and elaborate repertoires of hunting behaviour.
Wild hunting dogs still exist on the open savannahs of Africa - although man has
reduced their populations and distribution to such a dangerously low level that they
now face extinction. Aside from this, it is evident that the hunting dog way of life
has been successfully sustained for many millions of years without need for change.
Another example of stasis. At times, during this period however, there will have
been severe constraints (perhaps due to overpopulation) on some groups of these
animals with the result that some may have needed to change their habitat to continue
to survive. Some of these dogs could have changed their hunting grounds to a nearby
rainforest habitat and got themselves established there.
To successfully adapt to this new habitat, however, would mean many changes in behaviour
Hunting would need to be carried out on an individual basis rather than in groups
because hunting in packs can only occur successfully in a relatively open environment.
Ground-based prey would be targeted first as those living in the trees would be inaccessible.
The First Stages
So how could a group of these canids adapt to an arboreal lifestyle and begin the
process of primatisation (taking on monkey-like characteristics)? It might have happened
A hunting dog may have leapt up onto the branches of a tree in pursuit of its prey
but could not go any further. While it was up there, another prey animal may have
passed by below and the dog was able to drop down and seize hold of it.
A learned manoeuvre like this would be repeated time and time again and others would
begin to copy it. The technique would be demonstrated to offspring and the strategy
would be passed onto many successive generations.
So already, behaviour patterns of the hunting dog pioneering the new rainforest habitat,
will have begun to change quite considerably. Now we can start to think of them as
rainforest hunting dogs. They are on their way to becoming a new species because
they are developing in isolation from ‘true’ hunting dogs of the savannahs.
Future generations of these animals would produce variations wherein some were able
to climb further up into trees and perhaps reach alternative food resources such
as snakes, chameleons and lizards. There would be natural selection for those individuals
with these abilities over those which had not and, perhaps, individual animals became
smaller in size, to fit the demands of the new environment.