^w^ The jaws of the shark are not attached to bone. They are attached to the cartilage skeleton by muscles and ligaments.
^w^ When the shark opens its mouth to bite, the nose swings up and out of the way. The upper jaw protrudes, exposing the upper teeth, and the lower jaw drops.
^w^ The jerk of the head with large sharks is an instinctive motion to tear off a piece of the bait. Like most predators, sharks' teeth are not designed to chew, and they tend to select food they can swallow whole.
^w^ The bite force of a shark has been measured at 18 tons of pressure per square inch, strong enough to break through steel. But humans and many other animals also have an incredible bite force. It's the size of the jaw and the jaw muscle that makes a shark's bite so powerful.
