Dolphins and whales, belonging to the cetacean group, have undergone significant evolutionary changes to thrive in aquatic environments. Unlike their terrestrial relatives, these mammals have adapted by losing hind limbs and developing streamlined bodies with flippers and tails.
A recent study published in Nature Communications sheds light on how the vertebral column of cetaceans has been reorganized over millions of years. Researchers found that, contrary to previous assumptions, cetacean spines possess multiple regions, making them distinct from terrestrial mammals.
Lead author Amandine Gillet from Harvard University explained that as cetaceans transitioned to water, their spines became the primary structure facilitating movement in aquatic settings. This adaptation allowed them to navigate with agility and speed.
The study identified a hierarchical organization of the cetacean spine, consisting of a pre-caudal segment and a caudal segment, each divided into several modules. Depending on the species, these modules can have between six to nine distinct regions.
Interestingly, species living in open ocean environments tend to have more vertebrae and regions, which correlates with their swimming speed. In contrast, those inhabiting rivers and bays exhibit fewer vertebrae but possess more defined regions for enhanced maneuverability.
This research not only enhances our understanding of cetacean anatomy but also opens avenues for studying how these adaptations relate to swimming performance and habitat preferences.