What structural adaptation helps aquatic mammals efficiently catch food?

The elongated skull is a structural adaptation that helps aquatic mammals efficiently catch food by enhancing their hydrodynamic design. This adaptation allows for a streamlined body shape, which reduces water resistance while swimming and facilitates quick movements when pursuing prey. An elongated skull can also provide a longer rostrum (snout), which can be beneficial for capturing fish or other marine organisms. In addition, having a longer skull can improve the sensory capabilities of aquatic mammals, making it easier for them to detect prey in murky waters or during low visibility conditions.

This adaptation also allows for a better arrangement of teeth, which can be optimized for grasping slippery prey, further aiding in their feeding efficiency.