Skull Bone Anatomy of the Young Common Hippopotamus (Hippopotamus Amphibius)

Abstract

Abstract Hippopotamidae family is nowadays represented by two species within two different genera: pygmy hippopotamus (Choeropsis liberiensis) and common hippopotamus (Hippopotamus amphibius). The common hippopotamus has a very unique anatomy, and the shape of the body, especially the head is adapted for a semi-aquatic life style. The morphological examination and description of the gross anatomical features of the hippopotamus skull is described in this paper. The shape of the skull is adapted for the amphibian way of life. Their eyes, ears and nostrils are placed high on the roof of the skull which allows these organs to remain above the surface of the water while the animal is being submerged underwater. The skull is massive, but the brain case (neurocranium) is extremely small compared with the splanchnocranium and complete head. The dental formula of the common hippopotamus is: incisors (I) 2/2, canines (C) 1/1, premolars (P) 3-4/3-4 and molars (M) 3/3. Incisors and canine teeth are formed in the shape of tusks and are used for threat or “demonstration of power” among animals when vigorously fi ghting. Incisor teeth grow continuously and are twice bigger in males than in females.