Skull Measurements in the Northern Virginia Deer

Abstract

Several years ago it occurred to me that a large series of measurements of skulls of a selected species from a restricted area might be of general interest. In the first place, if the figures were carefully tabulated and subjected to a biometric analysis they might point out the values of the different skull measurements. By relative value I mean value to the systematist, as shown by their constancy (lack of variability). By working with sufficiently large series, it seemed that the coefficients of variability of the different skull measurements might be compared directly, one with another, and thus subjected to the acid test. Another question was that of the maximum and minimum variation within the race or subspecies, a study of which might form a basis for comparison with other races. It was also thought that in taking a large mammal, the actual technique of measurement was subject to less error, and as the northern Virginia deer (Odocoileus virginianus borealis) was the only large species available in any numbers, it was accordingly chosen. Special care was taken to throw out any specimens that were not fully adult, and after measuring 109 skulls of males, 13 of them, having an antler length of 38 cm. or under, were discarded, as being perhaps not fully developed. The remaining 96 specimens represent, in my opinion, a selected class of adult males with antlers between 38 cm., and 72.5 cm., and an average of 47.6 cm. The type of O. v. borealis in the Museum of Comparative Zoology has antlers 66 cm. long. A series of skulls of females was not available. All these deer heads came into the taxidermist shop of Mr. M. Abbott Fraser of Boston, and they were nearly all secured in the Boston market, being picked out because of their value for ornamental purposes. Practically all came from northern and eastern Maine, and possibly one or two from northern New Hampshire and Vermont. (One I am certain was from Vermont.) I am indebted to Mr. Fraser for placing this material at my disposal. It is probable that these animals are four years old, or older, and a few showed by their worn teeth that they had about reached the extreme age limit. 130