Anatomical structure of the orbits of the European beaver (Castor fiber)

Understanding the specifics of the orbit of each species is a fundamental and crucial step in developing veterinary ophthalmology. This article describes the bone structure, foramina piercing the bones, and the shape of the orbit in the European beaver (Castor fiber). Additionally, a morphometric analysis of the orbit was conducted, measuring its height, width, and depth, and the orbital index was calculated. A total of 27 skulls of this species were used for the study. It was shown that the average length and depth of the orbit were greater in females, while the average width was comparable in both sexes. Males, however, had a higher average orbital index. The observed regularities, assessed with a T-test, showed statistically significant differences between individuals. These results are the first step towards developing reference values for the discussed dimensions for this species, which will allow for the assessment of the correctness of the orbit structure of the European beaver.