The caudal vertebrae (tail backbones) angled down at the end to support a large upright fin, similar to the tail of a fish. Swishing this from side to side provided the thrust for speedy swimming.
The caudal vertebrae (tail backbones) angled down at the end to support a large upright fin, similar to the tail of a fish. Swishing this from side to side provided the thrust for speedy swimming.