Boros István (szerk.): A Magyar Természettudományi Múzeum évkönyve 2. (Budapest 1952)

Szunyoghy, J.: The effect of castration on the skull of the domestic cat, and the establishment of differentiating characters on the skulls of the domestic cat and the wild cat

First of all I wanted to know what place the skull of my castrated specimen fills in regarding male and female feline crania in relation to its sexual character. Accordingly, an investigation had to be made into the sexual characters of the male and female skulls of the demestic cat. It can be stated that there is no essential difference. The features and form of the brain case and the facial region of the skull, the direction of the profil, the form of the mandible (regardless of smaller individual abei rations) are the same in both sexes. On the skulls of very old (senile) males the processus zygomaticùs ossis frontalis meet with the processus frontalis ossis zygomatici. By this way the temporal fosse can well be separated from the orbit. I do not, however, maintain that this contact is characteristic of senile male skulls as there is a similar inclination in adult female specimens, though I have never as yet observed it. Investigation into the dentition shows that the more gross and stronger developed canines may be indicators for the male. To separate however the sexes on this base could only be effected by larger cranial series and not even then with security. As a corollary, my castrated male catskull

—orskulls — cannot represent a transitory form between the sexes, as it was shown in the case of some domestic animals. The skulls of castrated specimens conform with both sexual types of the domesticated cat and does not deviate from them either in the form of the.facial — and/or cranial skull or the jaws. In spite of this conformity they have characteristic thick and massive bones causing an abundant growth of weight in the skull. For example, the linea temporalis bordering the planum parietale — while showing only seldom and dimly on adult and senile male and female skulls — appears very markedly in castrated animals. A further character is the meeting of the processus zygomaticus ossis frontalis and the processus frontalis ossis zygomatici , the same as on the senile male skulls of the domestic cat. They also agree with the senile males in that the sutures of the os interparietale soon ossify. I have deliberately left till the last the one character by which the skulls of castrated specimens really differ both from normal male and female crania, and this is a growth in size. This increase is however only in bulk and does not mean any morphologic deviation. To illustrate differences in size I insert craniographic figures (T. I. II. 1—8.) in dorsal, lateral and ventral view (magnified on the same scale) of the castrated specimen and of the largest male and female in my possession, together with some craniometric values (see table). The skulls of castrated individuals attain or even exceed the cranial values of the much larger wild cat, as one of my examined specimen witnesses. It will not be then superfluous to compare the magnified skulls of castrated individuals — representing also typical Felis catus — and uncastrated ones with those of Felis silvestris, and try to state the morphologic differences as a base for the separation of the two species.

1 The skulls of the domestic and wild cat show a great similarity so that to distinguish between them is not an easy task. There are some authorities, e. g. Miller (1) and Bau mann (2), in whose opinion the two species cannot be distinguished osteologically or on their skulls alone. Again, there are others, to mention only Blasius (3), S a t u n i n, О g n e V (4), A. and G. Z i m m e r m a n n (5), who hold possible a separation on base of the skulls. 1 My examined material were 22 domestic cat skulls, 1 domestic and wild cat mongrel and 19 wild cat skulls. 178