Unlike bony fish, elasmobranchs possess a skeleton made entirely of cartilage. This remarkable material is lighter and more flexible, allowing for increased maneuverability in the water. Cartilage is also self-repairing, offering a significant advantage in the harsh marine environment. The intricate vascularization of the cartilage is a key factor in its resilience and ability to withstand immense pressure.
Elasmobranchs lack a swim bladder, a gas-filled organ used by bony fish for buoyancy. Instead, they rely on a unique mechanism called the buccal pump. By forcefully expanding and contracting their mouths, they actively push water out, creating an upward force that propels them through the water. This process is incredibly energy-intensive but provides unparalleled control and maneuverability.
Elasmobranchs possess exceptionally acute senses. Their ampullae of Lorenzini are specialized electroreceptors that detect the weak electrical fields generated by the muscle contractions of their prey. They also have heightened senses of smell and hearing, enabling them to locate food and navigate their environment with extraordinary precision. The ability to sense magnetic fields is also suspected in some species, potentially aiding in navigation and orientation.