The Ear

(The ears of humans are compared to those of primates and other mammals in position and degree of recessive development -- the pointed ears of other mammals are rounded, the apparent move of the ear of a new-born mammal towards the back of the head seems retarded in humans, etc.)

An even further recessive development of the ear has taken place with mammals who have specialised to a life under ground and in water. Considering the latter specialisation, B. Henneberg has shown through comparative studies that only the scapha itself has become more rudimentary, while the anthelix, tragus and antitragus and their corresponding muscles have kept the ability to close the ear canal when diving in water. He concludes, that the human ear also must have had this ability at some point in its development, an ability which seems most helpful to mammals who spend a lot of time emersed under water. Henneberg suggests that one shall search for persons whose ears' structure comes closest to that of the original, closable form. With these people, these muscles should be found to still be contractible. I myself know such a person, who I have searched for and found because of Hennegberg's work. Henneberg suggests that many questions impose themselves unto this problem, and that one could easily lose oneself in speculations. However, my consideration, that humans, based on the construction of kidneys and spleen, perhaps may have spent a period of time living as a sort of water mammal, has become less "speculative" through his observations of the ear.

(...) The condition of the "incomplete uniformation or consolidation" of the human spleen and kidneys has been surpassed only by one species of mammals, namely the Cetaceans, the whales (, dolphins and porpoises), compared to the kidneys of cows, of the pinnipeds, of seaotters and bear, hippopotamus and rhinoceros, in other words of animals, which used to or still live in or near water. Of special significance is the observation, that all new-born anthropoid apes have fully consolidated kidneys, as do the majority of mammals, while their spleen may in rare cases show remains of grooving; the consolidation has not yet reached its full extent. Humans (...) stand, in this respect, on one of the lower rungs of the ladder of evolution, while the anthropoids, their so-called closest relatives, as well as the other mammals have by far surpassed them in this respect. Whales, dolphins, seals, sea otters and bears seem much closer relatives to humans when we compare their spleen and kidneys than do anthropoids, who have by the way also developed remarkably far ahead of humans considering the consolidation of the aveolas of the lungs. These remarkable coincidences between such different species must naturally be interpreted as convergences. The fact that these species have a common environment, water, allows the consideration that in an early stage of human mammalian development there existed a being with an aquatic way of life.

The hypothetical aquatic mode of life?

The postulation of an aquatic mode of life during an early stage of human evolution is a tenable hypothesis, for which further inquiry may produce additional supporting evidence.
The shape of the human foot, broadening towards the front, could indicate a paludine habitat, especially when we note the observations of Mr O. Abel in his Palaeobiology (Stuttgart, 1912, pp. 229 – 30) where he discusses the secondary plantigradism of certain fossilised bog animals, for instance Mesodon and Coryphodon, whose footprint shows a remarkable similarity to that of humans, For such a mammal, moreover, a move to an aquatic environment would mean that powerful teeth would become unnecessary due to the relative softness of the available food resources.
The fact that man lacks hair – but probably was hairy at some earlier stage – suggests an analogy with the relative absence of hair in water mammals whale, sea-cow, hippopotamus), especially since so far there is no other plausible exp1anation. Another indication is the subcutaneous layer of fat in humans; its capacity for expansion appears to predate human civilization The so-called Venus statuettes, dating back to the Stone Age, support this assumption. The hitherto unsolved problem concerning pigmentation in humans may be related to this problem; rather than loss of pigment in the white races, the re may have been increased pigmentation in coloured ones, corresponding to the post-natal increase in pigmentation in children of all races.
In his latest book On the Significance of the Ear Muscle, Mr B. Henneberg also proposes an aquatic mode of life in the prehuman primate. He assumes that this ancestral hominid featured a contractile form of the ear muscle, with the anthelix tragus and antitragus) differing in shape from that of Homo, and that this origina1 form was subsequently lost during the transition to life on land. It is still easily possible to reproduce the original form in children by artificial means, and the original feature has in fact been observed in one living newborn baby. In his famous work Physiology of Movement [Philadelphia, 1949], Duchenne shows that electrical stimulation of the tragus and antitragus muscles in human beings is capable of closing the entrance of the ear, which is why he calls the two muscles ’constrictor conchae sup. and inf,’.
Man shares with the water mammals the regression of the olfactory organ, the bulbus and lobus olfactorius which, according to A. Kappera and Count Haller, is connected with a certain development in the conformation of the brain, not found in the macrosomatic animals,
As further evidence of an earlier aquatic way of living for man, one could also point to the existence of mucous glands in small benign tumours in the skin of man’s back which the Prague pathologist Schickel has investigated and which, in the absence of any other possible explanation, with reference to fish and frogs, he has called atavistic. Such mucous glands have survived as the normal condition in the hippopotamus as a physiological adaptation to its aquatic environment, while in humans they appear under pathological conditions about which little is understood.
To this can be added the not particularly rare web-like skin formation on the hand and toes seen also in Potamogale, the otter shrew), and the direction of the body hair towards the elbow on the lower arm in human beings and anthropoids, as well as in other apes and quadrupeds. The usual explanation, that the direction of the hairs functions as protection against rain when the arms are placed over the head, is too na7ve to be correct. Apart from the fact that the head does not even get covered, the water then would be conducted forward from the elbow between the hairs of the upper arm and thereby directly to the skin of the armpit and chest, which would hardly be advantageous, Even if this direction of the hairs were peculiar to man, I would see it as not insignificant support for my aquatic hypothesis, since such a direction of the hairs on the lower arm during swimming stretching the arms forward) would have been useful,
This summary should not be concluded without some reference to the ideas of the anthropologist, G. I.. Sera, in Naples. He takes the view that the form and development of the Adam’s apple, the shortness of the outer auditory passage, the form of the musculus glutaeocruralis (m. tenuisaimus), some characteristics of the female genitals, the formation of the kidneys, the form and development of the nasal cartilage, and the form of the ear muscle may constitute evidence of a possible aquatic phase in the evolution of the platyrrhine New World primates. And finally, I would point out that man’s way of mating is also the standard method among water mammals such as beavers, cetaceans and sirenians. The aquatic theory remains an open question. But such hypotheses, which at first sound so improbable, should at least serve as a stimulus to further research, on the principle that a good detective follows up the least promising clues as well as those which seem to point to a simple solution.

Bibliography

 

 

Abels, O.

Paläobiologie.Stuttgart. 1912.

Duchenne.

Physiologie der Bewegung.

Henneberg, B.

"über die Bedeutung der Ohrmuschel". Zeitschrift für Anatomie und Entwicklungsgeschichte, Bd 111, H 2. 1941.

--

"über die Ohrmuschel". Anat. Hefte, Bd. 40.

Krumbiegel.

edba. Bd 4. 1929.

Mertens, A.

Zeitschrift für Säugetierkunde. Bd 3 u. J. 1925.

Sera, G L.

Archivo Zoologico ItalianoVol XXV.1938.

Šikl.

Frankfurter Zeitschrift für Pathologie. Bd 43. 1932