Part 8

By the year 1843 the size of the brain of whales was being related to the total size of the body. The very large brains of the large whales were reduced in importance by considering their weight in a ratio to the weight of the total body. This type of reasoning was culminated with a long series of quantitative measures published by Eugène Dubois (Bulletins de la Société d’Anthropologie de Paris, Ser. 4, VIII , 337-376).

Descriptions from those of Hunter and Tyson onwards agree that, in absolute size, the brains are as large and larger than those of man. All were agreed that the smaller whales, i.e., the dolphins and porpoises, have very large brains with relation to their body size. It was argued, therefore, with respect to the dolphin, “this creature is of more than ordinary wit and capacity.” (Robert Hamilton, The Natural History of the Ordinary Cetacea or Whales, p. 66, in Sir William Jardine, The Naturalist’s Library, volume 7, Edinburgh, 1843.)

Tiedemann’s drawings of the brain of Delphinus delphis and of Delphinus phocaena were published by H. G. L. Reichenbach in his Anatomia Mammalium in 1845. The four drawings are shown in Figure 6. These drawings show the improved awareness of the complexities of these large brains in regard to cerebral cortex, the cerebellum, and the cranial nerves. Correlations between the structure of this brain and the behavior of the animal possessing it, were (and are) woefully lacking. The only behavioral accounts were those of whalers hunting these animals. Hunters tend to concentrate on the offensive and defensive maneuvers of the animal, and can give useful information for other kinds of evaluation of the animal’s behavior and presumed intelligence.

In 1787 John Hunter, writing in the Philosophical Transactions of the Royal Society of London (LXXVII, 423-424), said the following: “The size of the Brain differs much in different genera of this tribe, and likewise in the proportion it bears to the bulk of the animal. In the Porpoise, I believe, it [the proportion] is largest, and perhaps in that respect comes nearest to the human....

“The brain is composed of cortical and medullary substances, very distinctly marked; the cortical being, in colour, like the tubular substance of a kidney; the medullary, very white. These substances are nearly in the same proportion as in the human brain.... The thalami themselves are large; the corpora striata small; the crura of the fornix are continued along the windings of the ventricles, much as in the human subject.”

Flatau and Jacobsohn in 1899 wrote, “the large brain of the Porpoise is one of the smallest in the Cetacean Order in which the organ attains to a much greater absolute size than any other.”

In 1902 G. Elliot Smith wrote of the brain of a species of dolphin called “Delphinus tursio” (which may be the modern Tursiops truncatus): “This brain is larger and correspondingly richer in sulci than that of the porpoise: but the structure of the two organs is essentially the same.” His drawings are shown in Figures 7 and 8. He said further, “the brains of the Beluga and all the dolphins closely resemble that of the porpoise.”

Smith summarizes the discussion of the huge size of the whale’s brain. “The apparently extraordinary dimensions of the whale’s brain cannot therefore be considered unusual phenomena, because this enormous extent of the cerebral cortex to receive and ‘store’ impressions of such vast sensory surfaces becomes a condition of survival of the animal.

“The marvelous complexity of the surface of the cerebrum is the direct result of its great size. In order, apparently, that the cerebral cortex may be efficiently nourished and at the same time be spared to as great a degree as possible the risk of vascular disturbances [such as would be produced by large vessels passing into it], its thickness does not appreciably increase in large animals. [He then quotes Dubois’ figures showing that the whale’s cortex is the same thickness as that of the human.] Such being the case, it naturally results that the increased bulk of cortex in large animals can only be packed by becoming thrown into increasing number of folds, separated by corresponding large number of sulci.”

In regard to communication between individual whales, Scammon in 1874 wrote the following: “It is said that the Cachalots [Sperm Whales] are endowed with the faculty of communicating with each other in times of danger, when miles ... distant. If this be true, the mode of communication rests instinctively within their own contracted brains.” Let us not forget that Scammon was talking about the mammal with the largest known brain on this planet. Instinct as the sole cause of communication with a brain this size seems rather improbable. This brain is not any longer considered “contracted.” Both of these statements illustrate an authoritative view of that time. If one peruses the paper by Tokuzo Kojima, “On the Brain of the Sperm Whale” (in the Scientific Reports of the Whales Research Institute, Tokyo, VI, 1951, 49-72), one can obtain a modern clear view of this brain. The largest one that he obtained (from a 49-foot sperm whale) was 9,200 grams. The average weight of the sixteen brains presented in his paper is 7,800 grams for average body lengths of 50 feet. (The brain weight per foot of body length varied from 118 to 187 grams per foot, averaging 157; man’s ratio averages about 250 grams per foot.)

In the literature of the time of Scammon, the scholars failed to give us new information about the behavior of cetacea. There seems to have been a distinctly ambivalent attitude towards these animals which is continued today. This point of view can be summarized as follows: the whale is a very large animal with a brain larger than that of man. This brain is the result of the huge growth of its body. All of this large brain is needed to control a large body. Because these tasks are so demanding, there is not enough brain substance left for a high degree of intelligence to develop. Thus the large brain cannot give the degree of intellectual capability that man has.

As an example of man’s attitudes to cetaceans, consider the case of the U. S. Fisheries Bureau Economic Circular No. 38, of November 6, 1918, by Lewis Radcliffe, entitled “Whales and Porpoises as Food.” Roy Chapman Andrews is quoted as saying that hump-backed whale meat is the best of the larger cetaceans but that porpoise and dolphin meat is even better eating than that of the larger whale. The composition of the whale meat is given as 30% protein, 6% fat, and less than 2% ash. From a hump-back whale one obtains six tons of meat, from a Sei Whale, five tons, and from a Finback, eight tons. Directions are given to remove the connective tissue between the blubber and the muscle to avoid the oily taste. For those who are interested, the paper includes twenty-two whale meat recipes and ten porpoise meat recipes.

It can well be imagined, if we ever do communicate with whales, dolphins, or porpoises, the kind of reception that this sort of literature will receive from the cetaceans.

The limited point of view of the whales as “dumb beasts” neglects the adaptations that have taken place in non-mammalian forms with very much smaller brains but with comparable bulk of body. The 60-foot whale shark, a plankton eater, and like the rest of the sharks a water-breather, has a bulk of body comparable to that of the larger whales. It has a large brain cavity but a very small brain in a small part of this large cavity. (It is very difficult to find the weight of these brains to compare with that of the cetacea and other mammals.) The problem of brain weight versus body weight versus intelligence is most clearly expressed by Gerhardt von Bonin in his paper in the Journal of General Psychology (1937). He gives a very extensive table for mammals, their brain weight, their body weight, and the values of 2 parameters for their specification. He then states, “it is clear from all that has been said above that the figures given here are nothing but a description of facts, a description which, in the mathematical sense of the term, is the ‘best’ one. It does not pretend to make any enunciation about the relation of intelligence and brain weight. For that purpose we need a much broader psychological basis than we have at present.

“Former attempts to analyze the relations between body weight and brain weight suffer from three deficits: (1) they presuppose a correlation between intelligence and brain weight, (2) they make suppositions about the intelligence of animals which are unproven, and (3) they are based on a conception of cortical function which can no longer be considered valid.... There is a close correlation between the logarithms of brain and body weight, and this co-relation is linear. Brain weight increases as the 0.655th power of body weight. The value of the cephalization co-efficient k differs from species to species. Whether or not this is an indication of the intelligence of animals must be left to the psychologists to answer.”

One of the problems that the whales have, as compared to, say, the large shark, is breathing air while living in the sea. This requires that these animals reach the air-water interface relatively frequently—at least every one hour and a half for the bottlenose whale (Hyperoödon), three-quarters of an hour for the Sperm Whale (Physeter catadon), and every six minutes for Tursiops truncatus. This puts very stringent requirements on the relationship of the whales to other events within the sea. Each whale must know where the surface of the sea is at each instant and compute his future actions so that when he does run out of air he is near the surface. He is essentially a surface-to-depth and depth-to-surface oriented animal. He must travel at high speed at times in order to recapture enough air to continue whatever he is doing under the surface. This means that he must calculate his chances of obtaining a good breath of air during rain storms and similar situations. He can be violently thrown around at the surface unless he comes up in the trough rather than at the crest of the wave. Such calculations probably require an exercise of something more than just “instinct.”

Water-breathing animals, on the other hand, have no need for such calculations. If the surface gets rough, they move downward and stay there. The required maneuvers are very much simpler and the amount of computation is very much less.

This requirement for the whales implies that the information coming from every one of the senses, not just the skin, needs to be correlated very rapidly and in complex patterning to allow the animals to predict their future course safely and accurately. It also requires the use of large amounts of information from memory.

The predators of the sea, other than the whales themselves, make life in the sea rather a complex business for mammals. The very large sharks can and do attack whales, dolphins, and porpoises. At times such attacks are by overwhelming numbers of sharks on a relatively small number of dolphins. All of the older animals in our experience have at least one shark bite on them—the younger animals are protected by the older ones and most of them are not so dramatically scarred.

The whales, in turn, must track their own prey in order to obtain food. With the single known exception of Orca, none of their predators are air-breathers. In general, the whales’ diet consists of fish, squid, or other water-breathing organisms of the sea.

A scientific assessment of the position of these animals in the competitive environment of the sea is not yet fully evaluated quantitatively. Any pronouncement of the requirements in regard to new complex adaptations to new complicated situations and hence the evaluation of intelligence of these animals at this time is premature and presumptuous. The whole issue of the meaning and the use of these large brains is still very much unknown. As I say in Man and Dolphin, I am espousing a plea for an open-minded attitude with respect to these animals. It would be presumptuous to assume that we at the present time can know how to measure their intelligence or their intellectual capacity. The usual behavioral criteria used in evaluation of intelligence of other animals are obviously inapplicable to a mammal living in the sea. As McBride and Hebb so clearly stated, they cannot place the dolphin in any sort of intellectual comparative intelligence scale; they did not know the appropriate experimental questions to ask in order to compare the dolphins with the chimpanzees, for example. Comparing a handed-mammal with a flippered-mammal, each of which lives in an entirely separate and distinctive environment, is a very difficult intellectual task even for Homo sapiens.

In pursuing possible measures of intellectual and intelligent capacity, what line should one pursue? I explored this question somewhat in Man and Dolphin, but wish to summarize and extend it here in this discussion. The invariants that we are seeking somehow do not seem to be as concrete as “tool-making and tool-using ability” by means of the hands which has been one of the major alleged criteria for human adaptation and success. The chimpanzee and the gorilla have the hands but they do not have the brains to back up the use of the hands. Man has both the hands and the brain. Thus we can quite simply and concretely contrast the performance of the large brains of man with his hands to the smaller brains of the primates with their hands. When we consider the whales, we seem obsessed, as it were, with the necessity of our own nature to look for an analog of the hand and the manipulative ability. May it not be better to find a more general principle than just handedness and its use?

I suggest that we think more in terms of a physiologically appropriate set of more general mechanisms which may subsume several other human functions under the same principle. It seems to me that we must look for abilities to develop generalized dexterity of use for certain kinds of end purposes for any or all muscular outputs from the central nervous system. If there is a task to be done, such as lifting a stone, whether in water or air, a given animal may turn it over with his foot, with his flipper, with his hand, with his tail, or with any other body part with which he could obtain a purchase on the stone. The end task is turning over the stone, to obtain food or whatever. It makes little difference what kind of muscular equipment he uses just so he uses it appropriately.

Let me illustrate with a more complex example seen in our own laboratory. A baby dolphin was being nursed in a small tank artificially. It apparently needed the constant attention of a human attendant. Its mother had not been caught with it. After several days it discovered that if it banged on the bottom of the tank with its flipper in a rhythmic fashion it could bring the humans from the other room. (We heard a loud thumping sound transmitted from a hydrophone in its tank.) Previous to this it attempted to bring the humans from the other room by whistling the distress call of the dolphins; unlike its mother, the humans did not respond to the whistle. In a sense this distress call is in his instinctual pattern for obtaining food and aid by other dolphins. The secondary adaptation and the new effort was that of manipulating the flipper rather than the phonation mechanism in the blowhole. Thus driven by whatever the instinctual need is, it tried different outputs from its brain and finally discovered one which brought the desired results. This ability to change the output from unsuccessful ones to successful ones seems to me to be evidence of a “higher nervous system” function. Of course in fine gradation and small differences, the same kind of pattern can be shown for smaller-brained animals. It is the seeking a new output, not necessarily instinctually tied in, and the radicalness of the change of output, plus the relating of many of the variables to one another thus generating the new output, that seems to be the hallmark of the large brain. These problems are not single variable ones with simple cause and effect, but are simultaneous multiple variable ones.

Among the manipulable outputs (muscular groups) I would include those of respiration and phonation. The dexterous and finely differentiated use of these muscles generates all the complexities of human speech. As more of the physiology and psychology of human speech are analyzed and made part of our sciences, the sharper will be our criteria for separating man from the other animals, and from those with smaller brains. Scientific descriptions of human speech are of relatively recent origin. Scientific descriptions of the physiology of the vocal tract are anything but a closed book at the present time. The neuroanatomy and neurophysiology of speech is in a relatively primitive state of development as a science. With such a lack of knowledge of the intimate and detailed mechanisms concerned, it would be rather presumptuous to evaluate at the present time their role in the measurement and testing of intelligence and intellectual capacity.

However, I wish to point out that these factors are important in such an evaluation and become even more important in terms of evaluating a species that is not human. Thus it is necessary, in order to evaluate the intelligence of even the dolphins, much less the whales, to know something of their abilities in the areas of phonation and other kinds of bodily gestures and manipulations and hence in their abilities to communicate with one another. As I implied in Man and Dolphin, it is not possible to measure accurately the intelligence of any other being than that of a human being, mainly because we do not exchange ideas through any known communication mode with such beings.

The difficulties of such understanding as we can possibly gain of the real situation of the whales in the sea and their adaptation as mammals to this particular environment, can be illustrated by their use of sonic generators for the location of their prey and of the boundaries of their container by means of the perception of echoes. As is well known, the small mammals, such as the bat, use this mechanism in air. The bottlenose dolphin also uses this same kind of mechanism underwater. Because these animals are immersed in a medium of a density and a sound velocity comparable to the density and sound velocity of their own bodies, they can presumably use their sonar also in looking, as it were, inside one another’s body. The sonar view of the inside of the body of a dolphin may possibly be very instructive to other dolphins and possibly even aid in diagnosis of the causes of certain problems, especially of those of the baby by the mother. For example, their buoyancy depends upon maintaining their center of gravity below their center of buoyancy; otherwise they turn over and drown. If the baby develops gas in stomach #1, he can develop problems in his buoyancy relationship which turn him over; however, the mother dolphin can probably easily find out whether or not there is a bubble of gas in the baby’s stomach by her echo ranging abilities. When she discovers such a bubble, she can then burp the baby by banging on the belly with her beak. We have seen such operations take place in our tanks. Here is another instance of the animal using a given output, coupled with the proper input, to diagnose a problem and to manipulate other outputs in the solution of that problem. How much of this is labeled “instinctual,” i.e., “unlearned,” is purely a matter of intellectual taste.

In the sea it is necessary to use sonic mechanisms for sightings and recognition. If one goes into the sea one realizes that one’s range of vision even under the best of circumstances is rarely beyond 100 feet and most of the time is less than that even near the brilliantly lit surface of the tropical seas. With sonic means, one’s range is extended up to several miles under the best of circumstances and under the worst to a few hundred feet.