Anatomical study of the Iranian brown bear’s skull (Ursus arctos): A case report

Abstract

The Brown bear (<em>Ursus<br />arctos</em>) is a species at risk of extinction. It is considered the largest<br />carnivore and lives in northern Iran. Several studies on the structure of skull<br />have been accomplished in different<br />animals. The aim of this study was the inscription of gross anatomical<br />characteristics of skulls of three Iranian adult male brown bears that were<br />transferred to the Anatomical Department<br />of the Faculty of Veterinary Medicine of Semnan University. After processing,<br />that included cleaning, degreasing and bleaching, skulls were studied from the<br />dorsal or frontal, ventral, lateral, rostral, caudal and medial views. The<br />facial part of the brown bear's skull from dorsal view was small and the<br />cranium was seen quadrilateral and larger than the dogs. The facial part of<br />lacrimal bone and also the optic groove of presphenoid were absent. There was<br />not articulation between maxillary and nasal bones. The interincisive canal was<br />present and situated inter palatine processes of incisive bones. The orbital<br />cavity was small in brown bear. Lacrimal canal was formed by lacrimal and<br />maxillary bones. The interparietal bone and external sagittal crest in brown<br />bear were seen as being shorter than the dogs. Tympanic bulla was very small<br />and jugular foramen rounded. The external acoustic meatus was formed by<br />squamous and tympanic part of temporal bone. In conclusion, the brown bear's<br />skull has different important macroscopic characteristics compared to other<br />carnivores