The body of Basilosaurus cetoides was extremely long and slender, with a structure that made it look like a mix between a modern cetacean and a sea snake due to its serpentine shape. Its head was large and elongated, with a snout full of sharp teeth of different sizes, indicating that it was an active predator that hunted fish, sharks and possibly other smaller cetaceans. Unlike modern cetaceans, Basilosaurus did not have sophisticated echolocation, suggesting that it relied more on sight and smell to find prey.
Its hind limbs were vestigial, meaning extremely reduced and not functional for locomotion, revealing its evolution from terrestrial mammals. These small hind legs had no use for swimming, but were probably used during mating. In contrast, its elongated body was well adapted for swimming, propelling itself primarily with its tail, which had a caudal fin like that of modern cetaceans.
Basilosaurus cetoides lived in warm, shallow seas, which today correspond to areas including the Gulf of Mexico and part of the Atlantic. This cetacean is especially known from the numerous fossils discovered in Alabama, Louisiana, and other areas of the United States.
Basilosaurus cetoides represents an important link in cetacean evolution, showing a clear transition between ancient terrestrial mammals and modern, fully aquatic cetaceans. Although its body had some primitive adaptations, such as its flexible spine and vestigial legs, it was perfectly adapted to marine life and was one of the most fearsome predators in its ecosystem. This Eocene giant has been key to understanding the evolution of marine mammals and their total adaptation to the aquatic environment.
Approximate measurements of Basilosaurus:
- Complete 1:100 scale
- Length 51 mm
- Height 104 mm
- Width 28 mm
- Snout-tail length 190 mm
- Complete 1:50 scale
- Length 101 mm
- Height 207 mm
- Width 55 mm
- Snout-tail length 380 mm