This site is so compelling, it was hard to copy only part of it, and not the whole thing. I want to stress here, the evolutionary pressures would have been intense heat driving animals into water. This includes elephants, hippos, pigs- these almost hairless animals, lived in water, or wallow in water. If we include the geological and climate changes with the theory of evolution, it all makes sense.
Quote:
The Aquatic Ape Theory--Elaine Morgan
For example, we have a different way of sweating from other mammals, using different skin glands. It is very wasteful of the body's essential resources of water and salt. It is therefore unlikely that we acquired it on the savannah, where water and salt are both in short supply.
We weep tears of emotion, controlled by different nerves from the ones that cause our eyes to water in response to smoke or dust. No other land animal does this. There are marine birds, marine reptiles and marine mammals which shed water through their eyes, or through special nasal glands, when they have swallowed too much seawater. This process may also be triggered in them by an emotional excitement caused by feeding or fighting or frustration. Weeping animals, apart from ourselves, include the walrus, the seal and the sea otter.
We have millions of sebaceous glands which exude oil over head, face and torso, and in young adults often causes acne. The chimpanzee's sebaceous glands are described as "vestigial" whereas ours are described as "enormous". Their purpose is obscure. In other animals the only known function of sebum is that of waterproofing the skin or the fur.
The most widely discussed contrast between ourselves and the apes is that we have bigger brains. A bigger brain may well have been an advantage to early man, but it would have been equally of advantage to a chimpanzee: the question is why one of them acquired it.
One factor may have been nutritional. The building of brain tissue, unlike other body tissues, is dependent on an adequate supply of Omega-3 fatty acids, which are abundant in the marine food chain but relatively scarce in the land food chain.
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