The intelligence of whales has been the subject of speculation by writers since Ancient Greece.[1][2] The discovery of the large brains of the Cetacea in the eighteenth century led to inevitable comparisons of these brains to those of the humans and of the lower primates. The winds of scholarly opinions concerning the whales have anciently blown strongly for high intelligence but during later centuries shifted strongly against high intelligence. At the time of Aristotle (384-322 B.C.) the dolphin, for example, was held in high esteem, and many stories of the apparently great abilities of these animals were current.[2] By the time of Plinius Secundus (A.D. 23-79) the beginning of a note of skepticism was introduced. Plinius said, “I should be ashamed to tell the story were it not that it has been written about by ... others.”[1]
In the middle ages the strong influence of religious philosophy on thinking placed Man in a completely separate compartment from all other living creatures, and the accurate anatomy of the whales was neglected. This point is illustrated by [Figure 1], published in the 1500’s in Historia Animalium by Konrad Gesner. This was apparently a baleen whale. It has two tubes which apparently symbolize the double blowhole of the Mystacocetae. There is no modern whale known that has such tubes sticking out of the top of his head. There is a huge eye above the angle of the jaw. All whales have the eye at or near the posterior angle of the jaw. The eye is very much smaller than the one shown here. A print published in 1598 of the anatomy of these animals is shown in [Figure 2]. The drawing of the male organ is accurate (apparently it was measured with a walking stick), but the eye is too large and is misplaced.
These pictures illustrate very well man’s most common relationship to the whale, which has continued to the present day. For commercial reasons man continues to exploit these creatures’ bodies.
It was not until the anatomical work of Vesalius and others that the biological similarities and differences of man and other mammals were pointed out. It was at this time that the investigation of man’s large and complex brain began.
All through these periods intelligence and the biological brain factors seemed to be completely separated in the minds of the scholars. At the times of the Greeks and the Romans there was little, if any, link made between brain and mind. Scholars attributed man’s special achievements to other factors than excellence of brain structure and its use.
After the discovery of man’s complicated and complex brain and the clinical correlation between brain injury and effects on man’s performance, the brain and mental factors began to be related to one another. As descriptions of man’s brain became more and more exact and clinical correlations increased sufficiently in numbers, new investigations on the relationships between brain size and intelligence in Homo sapiens were started. The early work is summarized by Donaldson.[3]
In the late 1700’s and the early 1800’s the expansion of the whaling industry offered many opportunities for examination of these interesting mammals. Figures [3] and [4] are dramatic examples of the state of the industry in the late eighteenth and early nineteenth centuries.
One of the earliest drawings of the complex brain of one of the cetacea is that of Gottfried Reinhold Trediramus in 1818 ([Fig. 5]). This is an anterior view of the brain of the common porpoise Phocaena phocaena. This is one of the earliest pictures showing the complexity of the fissuration and the large numbers of gyri and sulci.
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 [1897], 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.)