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The Evolution of Two of Our Closest Relatives

The DNA of Humans, Chimpanzees and Bonobos is very similar.This is a fact, although there is much scope for disagreements about how close, and even more for interpretation of why it is close. The Theory of Evolution would explain the closeness by suggesting the three species evolved from a common ancestor.

This article is not about Evolution versus Creation, but is an attempt to explain the formation of two different species.

The Bonobo has only been recognized as a separate species by science since about 1928. For such an important animal this seems surprising, but its similarity to the chimpanzee fooled people. This was further confused by the existence of several distinct sub species of Chimpanzee.

As the two species were studied, many differences were found. At one time it was believed that Humans were the only creature to have sex face to face.  However, observations of the Bonobo showed that this animal frequently does the same. For more information about the sexual habits of the Bonobo, see Sex and the Bonobo. This is different from the Chimpanzee. There are very many physical, mental and cultural differences between the two species.

You might ask the question; "Can Chimpanzees and Bonobos interbreed?"  In the wild there are reasons to believe this never happens, but it does not  seem totally impossible to produce a hybrid between the Chimpanzee and the Bonobo under artificial conditions.  However, on the modern definition of species there is no doubt they are separate.

How did they separate? The answer to this seems simple. They both evolved from a common ancestor different from either of them, but two populations of this animal were separated geographically by the second mightiest river on our planet.  The Bonobo comes from the area to the south of the Congo River, while the chimpanzees occupy a much larger area to the North.

Like Humans, Apes cannot swim.  Before you object too much to this ridiculous statement, I should explain; most mammals can swim instinctively. Most Humans cannot; they need to be taught.  Apes are similar, so although there are rare reports of apes swimming, this is not usual, and that the mighty Congo River was a bar to travel by the apes on each side seems indisputable.  So Chimpanzees and Bonobos did not interbreed for a long time and have developed quite different strategies for survival.  This may be  partly because the areas they evolved in were not identical.

How well is the history of the evolution of these two species supported by the fossil record? This brings up an interesting point. The fossil record for some animals is good. The fossil record of the evolution of Humans is quite poor despite the effort put in by many brilliant and dedicated workers over many years. However, there are almost no fossils of the African apes.

Various reasons have been put forward for this, but my favorite one is that the animal that both the Chimpanzee and the Bonobo evolved from was one of the species of Australopithecus. The Bonobo seem remarkably like the reconstruction of Australopithecus, based on its skeleton, although the Chimpanzees and Bonobos have larger brains than Australopithecus.
Darwin might have liked the clear geographic separation that allowed the relatively gentle Bonobo to evolve without interference from the warlike Chimpanzee.

I hope the Bonobo and the Chimpanzee are allowed to survive.