Fifty years ago this question of how we evolved from ape to man was a laughably simple question. The ancestors of the apes stayed in the trees and our ancestor went out into the savanna plains. This paradigm explained everything. It suggests that we had to stand up on two legs to see over the tall grass, to chase after prey and to free our hands for tools and weapons. Furthermore, we got so overheated in the case we had to take off our fur coat and throw it away. For generations this was held to be true. However, in the nineties something began to unravel. The paleontologists began to look at the fossils of the fauna that were from the same time and place as the early hominids. What they found was that these fauna weren’t savanna species. Then they looked at the fossils of the herbivores, and they weren’t savanna herbivores. So what these paleontologists concluded was that our early ancestors were running around on four legs in the trees before the savanna environment even came into existence. This investigation is not a minority theory, everybody agrees with. Professor Tobias Bender from the University College London says, “Everything we have been telling you the past 100 years, forget about it, it was wrong. We have to go back to square one and start again.” Yet, academia didn’t want to go back to square on. For academia this recent discovery must have been a terrible thing. I mean they had this beautiful paradigm and believed it for generations. No one had ever questioned it. Furthermore, academia constructed further theories on top of it. They had relied on the savanna hypothesis of human evolution and now it has been whipped away from under them. So what happens when a paradigm is proven to be wrong? Scientists carry on as if nothing had ever happened.
The Irony of this paradigm collapse is that for this occasion scientists didn’t need to wait for another paradigm to come about. In fact there has been one waiting shadows. This buried theory, first proposed by Alister Harding in 1960, came to be known as the Aquatic Ape Theory. The Aquatic Ape Theory suggests that when our ancestors moved onto the savanna they were already different from apes. It suggests that the significant loss of body hair, bipedalism, and other characteristics evolved some time earlier in an aquatic or semi-aquatic environment, when the human and ape lines first diverged. Most of the features of human physiology are rare or unique among land mammals, but are common among aquatic ones.
Some scientists suggest that humans became hairless to prevent themselves from overheating in the Savannah. But no other mammal has ever needed to do this. A covering of hair can act as a defense against the heat of the sun. That is why even desert-dwelling mammals, like the camel, kept their fur. Another suggestion is to make sweat-cooling possible, but many species use sweat-cooling effectively without losing their hair. There is one simple conclusion that can explain this: Although the best insulation for land mammals is a fur coat, the best insulation in water is a layer of fat.
Humans are, without question, the fattest primates. Our bodies contain ten times more fat cells than would be expected in an animal of our size. It would be very unlikely for humans to develop this feature after moving to the savanna and becoming hunters. If a land predator becomes too fat, it will become slow. It cannot afford to gain weight. The tendency of humans to gain weight probably came from an earlier aquatic past. All infant primates are very slender, with almost no fat. Their lives depend on how well they can cling to their mothers and support their whole weight with their fingers; only human infants are born fat. They begin to gain weight before they’re even born and continue to gain it for several months. White fat, commonly known as baby fat, is very rare in new-born mammals. While white fat isn’t very good for supplying heat and energy, it is good for insulation in water and for buoyancy. The fat is bonded to our skin. If you were to skin a rabbit or a dog, or even a chimp, any fat under the skin would remain attached to the tissues underneath. In humans, it would come away with the skin, as it does in aquatic species.
Humans are the only mammals in the world that habitually walk on two legs. Compared with walking on four legs, bipedalism has many disadvantages. It’s slower. It’s somewhat unstable. It takes many years to learn, something that is unacceptable in land mammals, who need to be able to walk and run very soon after they’re born. It exposes vital organs to attack. It would have been much more difficult for our ape-like ancestors to walk on two legs. Only a drastic change in their habitat could have forced them to adopt a way of walking that they were so ill suited for. There is one common hypothesis that suggests they developed big brains and began making tools, then began using just their hind legs to walk so their hands would be free to carry tools and weapons. Now, however, we know that bipedalism came first. Perhaps their habitat became flooded. To keep their heads above the water when they came down to the ground they would have been forced to walk on their hind legs. There are two other primates today that can stand and walk upright when on the ground. The proboscis monkey from the mangrove swamps of Borneo. Also, the pygmy chimp whose habitat includes a large part of seasonally flooded forest. Both these ape developed bipedalism to adapt to their aquatic environment.
The human respiratory system is different from that of all other land mammals. In most mammals breathing is an involuntary action like the heart beat or digestion. However, humans can consciously control their breathing. This voluntary breath control is an aquatic adaptation. It is enabled because of a descended larynx. This can be found in aquatic mammals, such as seals, dolphins, whales. When a dolphin or whale decides how deep they’re going to dive they can guess how much air they need to take in. Furthermore, humans can breathe through their mouths as easily as they do through their noses. This is most likely an aquatic adaptation, because a swimmer who needs to gulp in air quickly can inhale more of it through the mouth than through the nose. This is a common trait of marine or aquatic mammals.
The Aquatic Ape Theory attempts to answer a lot of unanswered questions that have plagued mankind about our heritage. The answers may be speculative, but no more than all of the other theories. The simple fact is that we love the water and feel comfortable in it. Some women even prefer to give birth in the water. We have swimming pools and Jacuzzis for recreation in the water. People have always been fascinated by the ocean and it has inspired some of the greatest stories and adventures. 90% of all life on earth evolved in the water, so is it unreasonable that our ancestors might go back to the most abundant food source in the world, the ocean? Something in our past changed us and put us on a course to what we are today. Our ancestors started walking upright on their hind legs becoming bipedal; the hair on their bodies changed direction and they became naked; they became fatter; they forgot how to pant;; their nostrils started to point downward; and they learned to speak. The Aquatic Ape Theory explains how all of these things could have happened.
Morgan, Elaine (1997). The Aquatic Ape Hypothesis. Penguin.
Bender, R.; Tobias, P. V.; Bender, N. (2012). “The Savannah hypotheses: Origin, reception and impact on paleoanthropology”. History and philosophy of the life sciences 34 (1–2): 147–184.
Hardy, A. (1960). “Was man more aquatic in the past” (PDF). New Scientist 7: 642–645.