Broca then proceeded to present arguments against the hypothesis that the marks on the fossil bones of
Here Broca seems to be thinking that the shark would completely devour the whale carcass, thus breaking apart the rib cage. Given the feeding frenzies of sharks, especially the great white shark, present in the Pliocene as
Some years later, de Mortillet (1883, p. 62) suggested, in
Broca continued: “Among the incisions, the majority penetrate obliquely into the bone. One of the sides of the V-shaped incision slices into the bone at a small angle, departing only slightly from the horizontal plane of the surface of the bone; while the opposite side, shorter than the first, is abrupt, almost vertical. The incision shows breakage. That is to say, the cutting action results in the separation of a small shaving of bone, broken at its base [Figure 2.1]. The cutting action of a sharp edge produces marks of this type. I don’t believe that the teeth of any animal could produce the same effect” (Capellini 1877, p. 58). The same thing was admitted by de Mortillet himself, who raised the point in his discussion of the bones of St. Prest (Section 2.1).
“Finally,” said Broca, “—and I insist on this point, which Capellini touched upon only lightly—the direction of certain of the marks is incompatible with the idea of a bite. The jaws do not execute such a movement. They open and they close.
The sort of curve described by a tooth rests always on the same plane. The incision produced by a pointed tooth on a hard surface, convex and immobile, is of determinate form. It is that of a plain curve, from one point to another by the shortest path, like a meridian on the surface of a sphere. The majority of incisions before our eyes do not present such a character. Here is one among others in which the direction changes many times [ Figure 2.2]. . . . the whole incision is made up, first, of a path perpendicular to the axis of the rib, then another longitudinal path, and finally an oblique one. It is a turning movement that a jaw could not make. The human hand, on the contrary, is capable, because of its multiple articulations, of perfect mobility, of guiding and inclining in every direction over the surface the instruments with which it is armed” (Capellini 1877, pp. 58–59).
Figure 2.2.
A Pliocene whale scapula from Monte Aperto, Italy, with cut marks similar to those described by Broca (de Quatrefages 1887, p. 97).Even though there may be some justification for pursuing the shark hypothesis with regard to the markings on the Pliocene whale bones of Italy, there is no reason to immediately abandon the hypothesis of human action, for which there is a great deal of evidence.
It is interesting that Broca, one of the foremost authorities on bone physiology of his time, favored Capellini’s view that the marks on the fossil whale bones were the product of intentional human work. Perhaps not all of Broca’s observations about the action of teeth on bone are correct. But this does not detract from Capellini’s conclusions, which were founded on years of painstaking research, and not on Broca’s extemporaneous statements.