Swimming Monkeys?

One of the subjects I have been studying since childhood has been evolution. Long before I knew of Wallace and Darwin, simple things in the natural world has intrigued me. I grew up surrounded by animals, and the favourite weekend pastime for my parents used to be trips to the Alipore Zoo. It was a heartbreak for me when "Adwaita", a Giant Aldabra Tortoise which was brought from Seychelles and gifted to the zoo in 1875, died in 2006 at a ripe age of 250 years! It was born around the Battle of Plassey in 1757! Astonishing! 

The great fascination with animals continued during my days at the Aurobindo and National Libraries, where I read any book I used to find on animals. However these days I am more focussed on the human species, and have been decoding many aspects which I never thought to be unique developments among our species. Like body hair for example. Hair is a multi-billion dollar industry, but it is also one of the great mysteries of evolution. 

The debate is so pronounced that Hair, or the lack of it thereof, has been the core point of debate in the two theories of human evolution. The savannah theory which is well established and the much recent but extremely convincing aquatic ape theory, which to most evolutionary biologists seems like blasphemy. It is pretty much like the geocentric or heliocentric models of the universe in the 15th century. However unlike the universe debate, there can be two winners in this case, as it is very mch possible that humans actually took something from both the sea and the savannah, in that order. 

In brief the Savannah Theory proposes that the onset of drier conditions severely reduced the amount of wooded habitats. During this period, when the forests became thin, early hominids adapted to an environment which was now more like the liminal forest-savanna mosaic zones of equatorial Africa. Consensus amongst scientists has the following sequence occurred:

• When human predecessors in the African jungles became overpopulated, some of them were forced to live on the open plain or savannah.
• Having to hunt game for food, they learnt to stand on their hind legs to see their prey more easily
• Because it was so hot out there, they shed their hair to enable sweat to flow freely
• Speech and intelligence grew from the need to communicate and hunt in packs

Hence humans evolved. 

However, the Savannah Theory is riddled with conundrums, such as:

• Primates such as baboons and vervet monkeys live on the savannah - they have not become bipedal, nor have they lost hair
• The many thousands of years it took to evolve from being able to move quickly on four legs, to beings able to run on two legs, would have left the prototype humans extremely vulnerable to predators.

Mammals are not designed to walk vertically, because it is grossly inefficient. If the first apes attempted it, they would have been like year old babies: falling over all the time. Furthermore, the “missing link” would have lacked the locking mechanism of the knees that we have today. Imagine trying to stand with your knees bent for a few hours. Without a high priority reason to do so, the human predecessors would have simply given up. 

Evolution does not have an agenda. It didnt happen exclusively to humans to give us a clear advantage over other species, which resulted in various bodily changes, which ultimately culminated in us becoming the most intelligent of all species. Then why did we suddenly make an effort to walk on two legs? 

The necessary trigger would have to be spread over a million years in order for the genetic modification in the anatomy, which is massive, to have taken place. So this trigger would have to be within the natural environment around, from which due to circumstances the early humans did not move out, till the changes had fallen in place. Only with the changes in place, were the humans able to move out into the continent, and start the savannah theory. 

The savannah theory does not explain the large brain size. The savannah theory is not possible without a large brain. Pack hunting and survival in an open environment takes considerable intelligence for such a frail species like humans to survive. We dont know how to swim, to fly or to run fast. We dont have camouflage, or poison or claws. We dont have armour, or horns or night vision. Without any of these defensive mechanisms it is highly improbable that the humans would have survived evolution at all in the wild and unforgiving savannah, with many more deadly carnivorous hunters than what is there in Africa now.