aquatic ape theory

[...]Humans are so accustomed to erect locomotion that it takes a specialist to appreciate what a bizarre and costly adaptation it was. Owen Lovejoy commented: " "For any quadruped to get upon its hind legs in order to run is an insane thing to do. It's plain ridiculous." As a gait it is far more unstable than quadrupedalism; it takes very much longer to learn, greatly extending the period when the female is burdened with the task of carrying the infant; it is a deplorably ineffective defence posture, exposing the most vulnerable organs of the body to the risk of damage or evisceration; unlike in quadrupeds damage to one leg or foot can be crippling rather than a temporary inconvenience. For bipedalism to become as efficient as it is today required extensive remodelling of the body, affecting the cranium, spine, pelvis, legs, feet, and consequent adaptations in the muscles and other organs. After five million years of these modifications, the spine is still the first organ in our bodies to deteriorate due to wear and tear, and bipedalism is the direct cause of vascular disorders such as varicose veins and haemorrhoids, and of obstetric disorders that throughout most of history have been life-threatening.

[...]The original assumption concerning human nakedness, that the hominids shed their body hair to avoid overheating, offered no valid reason why they would have been more at risk from overheating than other species sharing the same habitat. It ignored the fact that depilating an animal on the savanna raises its core temperature, rather than lowering it The argument that nakedness must have been a necessary concomitant of sweat-cooling is invalidated by the example of the thick-coated but efficiently sweat-cooling patas monkey. The progressive shortening of body hairs until they were functionally useless was not an extrapolation of any existing primate trend. Russell Newman convincingly argued that hairlessness must have preceded the move to the savanna; but the feature is no more frequently encountered, and no more easily explained , in a forest habitat than on the open plains. Human skin also differs from that of primates in respect of its greater thickness and elasticity, a radical transformation of the skin glands, and the way it is connected to a layer of fibrous tissue and a fat layer, described by John Napier as "one of humankind’s greatest unsung hallmarks" and found elsewhere only in aquatic species. William Montagna after years of exhaustive research into all aspects of primate skin, reported in 1972 that the problem of human nakedness continued to defy solution.

[...]While speech is unique to humans, the physical modifications that made it possible are not. Humans but not apes can consciously exert control over the volume of air they inhale, how long they hold it, and how quickly they exhale it. The only other mammals known to be capable of this are diving mammals. It was an essential precondition of speech and the lack of it in apes is an entirely sufficient explanation of why they cannot be taught to speak. Another feature found in adult humans but no other land mammal is the descended larynx which has lost all connection with the palate. This arrangement has several disadvantages and it has been persuasively argued that it is a main factor contributing to the phenomenon of SIDS (crib deaths). One possible advantage to an aquatic hominid could have been that it facilitates mouth-breathing and makes it possible to inhale large volumes of air very quickly. The theory that it evolved in order to make speech possible, or was a precondition of speech, has now been invalidated. Professor Tecumseh Fitch of M.I.T. in Boston has examined a little girl of four years old in whom the larynx has never descended, but her speech is indistinguishable from that of any other child of her age.

[...]Homo has been described as an obese species; even the slimmest human has the potential for obesity since humans inherit ten times as many adipocytes as would be expected in a mammal of our size. The percentage of fat in a human neonate is greater than that of any other newborn land mammal . It is more than in the harp seal or the sealion, and about six times as much as in a baboon. After birth the baby - despite the high energy requirements of its growing brain – continues to devote roughly 70% of its growth potential to increasing this fat deposit, reaching peak adiposity of around 25% of its body mass by the age of nine months. These facts would not be predicted. either as part of the inheritance from early arboreal ancestors nor as adaptations to a life on the plains of Africa.

[...]The attribute of fat to which least attention has been paid is that it provides buoyancy. The amount of fat in diving mammals is liable to vary according to whether they are surface feeders, or deep divers for whom too much buoyancy would be an embarrassment. It is worth noting that a human baby – apart from adapting happily to the water if introduced to it early enough – will float, whereas a chimpanzee or gorilla infant would sink.

[Source: http://users.ugent.be/~mvaneech/Morgan.html]

Elaine Morgan site, withe her latest book available for free download: http://www.elainemorgan.me.uk/