Insight into the Functional Gross Morphology and Morphometry of the Cerebral Hemispheres and Olfactory Brain, and Sexual Dimorphism of the African Striped Ground Squirrel (Xerus erythropus)

This study was undertaken to document the normal features on gross morphology and morphometry of the olfactory brain and cerebral hemispheres of both sexes of African striped ground squirrel (Xerus erythropus) and to discuss the structure-function paradigm. The study was conducted by direct observation of ten (10) adult African striped ground squirrels comprising of five males and five females. The main morphological features were: a) a large club-shaped, non-pendulous olfactory bulb projecting from the cerebral hemispheres ventro-rostrally; b) cerebral hemisphere devoid of sulci and gyri; c) a well-developed corpus callosum connecting the cerebral hemisphere; and d.) a fornix which appeared as an arch shaped commissural fiber, consisting of a crus, a body and a commissure. Morphometric data values indicated that the males had statistically significant higher body and brain weights than the females. There was no significant statistical difference between sex in the mean values of the olfactory bulbs and cerebral hemispheres weight and dimensions (length and width). A significant statistical difference between sexes was reported with respect to the weight of the olfactory bulb (0.46 ± 0.03g in males and 0.32 ± 0.01g in females) and cerebral hemispheres width (1.87 ± 0.03cm in males and 1.79 ± 0.01cm in females). The well-developed corpus callosum and fornix, a very crucial organ in the function of formation and consolidation of memory, and the large size of the olfactory bulb, an organ for olfactory acuity supports the use of this rodent model for precise radio-tracking and identification of location.