View Full Version : Up from the Ape - Ears [by E. A. Hooton]

Wednesday, February 4th, 2004, 07:45 PM
by E. A. Hooton


Hearing begins with the evolution of land-dwelling vertebrates. In a previous section I have discussed the origin of the ear passages from the spiracular gill cleft of fishes and the transformation of certain bony elements of the reptilian jaw into the ossicles which transmit the sound waves to the inner ear (p. 62). There is little or nothing about the ear in man that is characteristically human. Most of the stages of auditory evolution are completed in the monkeys of the Old World.

The organ of hearing is lodged in the temporal bone, a portion of which projects wedge-like toward the center line of the skull and forms an important component of the skull base. It is in this petrous (rocky) portion of the temporal bone that the middle and internal ear are situated. In man, the anthropoid apes, and the Old World monkeys, the passage leading into the ear is surrounded by a bony ring (the tympanic bone) which is immediately behind the socket to which the lower jaw is hinged. This tympanic ring is expanded to enclose a chamber and forms an auditory bulla (knob) at the side of the skull base in New World monkeys, tarsioids, lemuroids, whales, and many lower mammals.

In man there are blunted conical bony processes of the temporal bone extending downward just behind the ear. These are called the mastoid processes. To them are attached muscles which run obliquely down the side and front of the neck and take their origins from the breast bone and the collar bone (Fig. 32). In addition to other functions these sternocleidomastoid muscles serve to rotate the head in one direction or the other so that the external ear is presented in a favorable position to catch sound waves. These muscles are present in some form or other in all of the primates, but reach their highest development in man. The conical process of the temporal bone to which they are attached, the mastoid processes, are found only in the gorilla and in man, being well developed in the latter and rudimentary in the former. The free poise of the human head upon the spinal column as a result of the recession of the jaws, the backward growth of the brain, and the erect standing posture, are, no doubt, responsible for the development of the mastoid processes and for the great mobility of the head in rotating movements. Man has also acquired a potential disability with the growth of this new feature. The bone cells inside the mastoid processes sometimes become infected from the ear or in some other way and cause the very serious disease, mastoiditis, to relieve which it is necessary to chisel away the hard bony covering of the mastoid region in order to drain the infected bone cells.

The first appearance of an external ear is represented by a fold of skin in certain lizards and owls. In many mammals the ears are long and pointed or covered with a flap of skin. The ears of lemurs and tarsiers are erect and more or less pointed and conform in general to the mammalian type. They can be "cocked" in one direction or another to catch sound waves. In the higher primates the habit of sitting erect and the free rotating movements of the head are thought to have brought about a reduction in size of the external ear and, to a great extent, the loss of its mobility. This is presumably because the head is now turned so that sound waves strike directly upon the ear, instead of the ear itself being moved.


The only part of the external ear which is degenerate in man is the portion which represents the ear flap or free tip of the ear in mammals. This flap originally served not only to catch sounds but to close the auditory passage. The external ear in apes, monkeys, and man is composed of a fibro-cartilaginous framework covered with skin. In man a rolled rim passes up from the anterior root of the ear over the top and down its hinder surface. This is called the helix. Concentric with the helix and inside of it is a ridge called the antihelix. This is generally forked in its upper portion. Inside the antihelix is the deep concha (shell of the ear) from the anterior part of which the auditory passage enters the skull. A flap called the tragus overlaps the auditory opening in front, and below and behind it is a smaller flap called the antitragus. The lowest part of the ear is the lobe, which contains no cartilage. In the process of evolution the root of the ear which is attached to the side of the head has not been reduced but has increased in area. (Fig. 33). The free tip, on the other hand, has been progressively shortened until in man, the orang-utan, and the gorilla, it has disappeared or is represented only by a tubercle or point on the inner edge of the rim of the helix, which is known. as Darwin's point. In monkeys, only the portion of the helix just above its root shows any rolling or infolding and the free point of the ear is still distinguishable. Among the anthropoid apes the helix is least rolled in the chimpanzee and shows the deepest infolding in the orang-utan (Fig. 34, p. 197). Both the orang and the gorilla have relatively and absolutely smaller and more degenerate ears than man, but the chimpanzee usually retains fine large ears. A progressive feature found in the human ear and in that of the orang-utan is the elevation of the antihelix so that it pro-trudes to catch the sound waves. The lobe is absent or rudimentary in the anthropoids and best developed in civilized races of man. It is a new feature which apparently serves no useful purpose, unless it is pierced for the carrying of ornaments, tobacco tins, or what not.


No experimental studies of the sense of hearing in the anthropoid apes have been made. Such comments and observations as are available seem to credit all of these animals with considerable auditory acuteness-equal if not superior to that of man. Sound discrimination in the gorilla and in the chimpanzee has been definitely noted by Yerkes.

The ear shows many individual variations in man, as is to be expected in an organ of which portions show distinct degeneration. Some persons have large, outstanding "chimpanzee" ears, with little roll of the helix and the free tip still visible in a nodule on the unrolled rim. More have the "orang" type of ear which is small, with a deeply rolled helix and a prominent antihelix. A helix pointed at the top is called a "Satyr point" and occurs in some human beings and occasionally in the gorilla (Cf. Fig. 54, p. 434). The muscles which move the ears in lower animals are reduced in size in the higher primates and are often impotent. Some talented persons are able to move their ears forward and backward as a result of these muscles being less vestigial than in the ruck of human beings.

It is evident that the organ of hearing in man takes on a new and increased importance in the reception of the sounds of articulate speech. But the auditory apparatus is no longer of primary use in detecting sounds made by enemies. Perhaps one may conjecture that the greater reduction of the ear in the gorilla and in the orang-utan as compared with man may be connected with their failure to use their ears as receptors of speech and with the fact that their size and strength make it unnecessary for them to bother about hostile sounds. But what about the chimpanzee? Does that anthropoid hear better or find it necessary to hearken to threatening sounds? Probably the differences between the various anthropoids and between them and man are, to a great extent, the result of hereditary, non-adaptive modifications.

Ears seem to be the least noticed of human features, unless they are unduly prominent. Ordinarily we look at the faces of people, not at their ears. It used to be the fashion, however, among students of criminal anthropology to pay minute attention to the variations of the form of the external car in criminals. There was a theory, to the effect that people with warped minds and anti-social tendencies were likely to have misshapen or peculiar ears, on the general supposition that degeneracy was likely to manifest itself externally in the form of this organ. Examination of criminal ears does show a great number of malformations and anomalies; but examination of the same organs in respectable, law-abiding, and eminent citizens indicates very clearly that almost any kind of an ear is likely to occur in the best of families. The form of the external ear is a variation of little or no functional importance; hence any particular ear form is not likely to interfere with its possessor's chance of survival. Consequently all forms occur and are transmitted with impunity.

Ears escape notice unless they are outstanding and obtrusive. Yet they are individually characteristic-so much so that criminologists measure, classify, and describe them in minute detail. Mozart had a peculiar anomaly of the pavilion of the car, but it probably had nothing to do with his musical genius. When I travel in the subway I often look at ears. Most of them are mediocre and those which are interesting are usually ugly. I once knew a girl who was very beautiful except for her ears, but I always had to look at those ears. They were long, flaccid, fish-belly white appendages, which looked more like bleached oysters than shells. If that girl has any children I hope they have not inherited her ears.

The external ear has been put by man to uses other than that of catching sound waves. The upper part of the ear may serve as a rest for spectacle bows, pens, pencils. The lobe is pierced by women and savages to receive ornaments and by doctors to extract blood to find out whether the owner of the ear is anemic. Yet this useful organ is little known in its racial variations.


Negroes and Negritos have short, wide ears; white races have longer and narrower ears; the longest and relatively the narrowest ears seem to occur in Mongoloid peoples. Professor R. B. Bean distinguished among the natives of the Philippine Islands at least eight types of ears, each of which he thought was associated with a definite cranial, facial, and bodily morphology. Most of these ear types also occur in Europeans. Bean's observations require confirmatory studies.

The only distinctive racial type of ear known to me is that of the Bushmen and Hottentots of South Africa (Fig. 54). This is a short, broad ear, with a very deep roll or infolding of the helix (rim). The upper border lies very close to the head and is sometimes attached to it. This superior border runs back almost horizontally, making an approximate right angle with the hinder border. The lobe is very small or absent and there is no "Darwin's point." This Bushman ear seems to be a variant of the Negro ear which is usually small and round with little or no lobe. The lobe is most developed in Europeans and Mongoloids, but these stocks oftener show a comparatively unrolled helix and more frequently have the cartilaginous knob or point on the edge of the helix where the upper and hinder borders join (Fig. 54). This "Darwin's point" is, of course, the vestige of the free tip of the mammalian car (Fig. 33, p. 196).

The attached or "soldered" ear lobe is a more primitive feature than the free lobe and probably occurs oftener in Negroids than in Whites. But it is scarcely possible to assert that the ear of the White is more highly evolved than that of the Negro or vice versa. The small Negro ear with its deeply rolled helix is certainly not primitive. A primitive ear should be large, with an unrolled helix. The chimpanzee is the only anthropoid with an ear unreduced in size and even among chimpanzees the bald-headed variety is said to display this "stigma of degeneracy." European ears are more chimpanzee-like than those of Negroes, because they are larger and oftener have unrolled helices. The lobe of the ear which is well developed in Europeans and Mongoloids is thought by some to be a progressive feature. But it sometimes occurs in the small and otherwise degenerate ear of the gorilla. I am inclined to regard the lobe as the useless, fatty excrescence of a vestigial organ.

Abby Normal
Wednesday, February 4th, 2004, 11:50 PM
You should make a poll about what type of ears the people on this forum have! That would be very interesting.

I almost definitely have "high type" ears. The "low type" ears look kind of funny and cartoonish for some reason... :D

Friday, September 8th, 2006, 06:51 PM
i was just wondering if the ears of a person define what race they are
is it an accurate analysis of their racial foundation
could anyone post any pictures detailing the differences???

Friday, September 8th, 2006, 11:49 PM
Elves have nice pointy ears. :)

Seriously though, it probably is a racial trait. If one's nose, occular structure, cheekbones, jawline etc. all vary by race, shouldn't ears too? Maybe one of the experts on taxonomy could offer an answer.