The hippopotamus is a large semiaquatic mammal native to sub-Saharan Africa and have barrel-shaped bodies with short tails and legs, and an hourglass-shaped skull with a long muzzle. Their skeletal structures are graviportal adapted to carrying their enormous weight, and their dense bones and low centre of gravity allows them to sink and move along the bottom of the water. Hippopotamuses have small legs because the water in which they live reduces the weight burden.
The eyes, ears, and nostrils of hippos are placed high on the roof of their skulls. This allows these organs to remain above the surface while the rest of the body is submerged.