A Sawshark, with its distinctive, flattened, sword-like snout.

Sharks have evolved a wide range of feeding mechanisms to cope with the demands of their varied diet. The loosely attached structure of the jaw, in particular, allows them to protrude their upper jaw forwards. Combined with a startling array of tooth designs, this flexibility of the jaws has led to feeding techniques that include, not just the gouging and cutting exhibited by the movie-star species, but sucking of food from the sea-bed for crushing and grinding too.

In the plankton-feeding species, such as basking sharks and whale sharks, evolutionary feeding adaptations have completely changed the shape and size of the jaw, greatly reducing the size of the teeth and modifying the gill structure so they became huge plankton sieves. Thresher sharks, even use the elongated upper lobe of the tail to strike at schools of fish and stun them before eating them.

Perhaps the most dramatic feeding adaptations are seen in the saw sharks and sawfish, which have developed distinctive flattened sword-like snouts armed with blunt teeth that the fish uses to stun smaller fish and other creatures.