Dental Caries in Wild Bears

Abstract

E. RAYMOND HALL University of Kansas, Lawrence Of American, wild-taken bears, 384 specimens (195 subgenus Euarctos, black bears and 165 subgenus Ursus, grizzly and big brown bears) in the collections of the University of California Museum of Vertebrate Zoology and the University of Kansas Museum of Natural History were examined for dental caries. Six Euarctos and three Ursus, or nine bears in all (2 per cent), had dental caries. Of 3,401 other specimens of wild-taken American carnivores and 2,256 insectivores examined* in the first-mentioned collection, no instance at all of dental caries could be found. Why should bears, alone, among these animals have dental caries? In pondering this question a person recalls first that bears, among all the Carnivora, have molars with low rounded crowns which most resemble the corresponding tooth-surfaces in man. The suggestion, then, is that in these two kinds of animals, bears and man, so extensively affected by dental caries, the occlusal faces of the teeth because of their characteristic topography may in some mechanical way, now unknown, lend themselves, better than in other animals, to penetration of the enamel and decay of the dentine. On second thought, I recall that the abovementioned similarity in toothform is probably an adaptation to an omnivorous diet and that other mammals of unrelated kinds that are omnivorous have molar crowns of corresponding form-pigs (Suidae) and peccaries (Tayassuidae), for example, have similar teeth but I have no knowledge of the frequency of caries in their wild (free-living) populations. By thus remarking on a general similarity of food habits (omnivorous as opposed to, for example, carnivorous, insectivorous or herbivorous), one is led to consider diet itself and the question of whether there be a parallel between, on the one hand those dentally carious persons among men, and on the other hand the bears, similarly afflicted among the Carnivora. In the voluminous literature on dental caries,t students of the subject commonly maintain that a