The Predator in the Corner
"Cat people" love their cats. And when their cats love them back, they tend to bite--or rather almost bite--the hand that feeds them. Domestic cats, like the big cats of the wild, have an exceptionally strong bite that they use not only to catch prey, but also to carry their young from place to place, sometimes in a hurry if a larger predator is in the area. House cats have a shorter history as companion animals than do dogs. By temperament and habit, they are more self-reliant and are closer to wild than our canine friends. The secret to the cat's incredibly strong jaws is found in its anatomy and evolution.
The cat has a broad, flat face. This makes its mandible, or lower jaw, very short. Strong muscles, called the temporalis and masseter, connect the mandible to the skull. Since the cat does not chew but rather tears its food, these muscles are large and well-developed. The shortness of the cat's jaw increases its effectiveness. Both muscles attach to the skull at a bone called the zygomatic arch. Mr. Cat, with his wide, flat head, has a longer zygomatic arch and therefore more room for a massive temporalis muscle. Since the cat's jaws only move up and down, not side to side, these muscles must be strong enough to shred prey so that it can be swallowed conveniently. Scientists have also found that animals with smaller brains, relative to the size of their heads, tend to have larger jaw muscles. So the bone structure and musculature of the cat's head and jaw are specialized in terms of geometry and mass to make it an efficient carnivore.
Early cats did not have as strong a bite as modern-day house cats for several reasons. They were much larger cats and tended to be able to bring down larger prey, providing more food for their families in less hunting time. The second reason was that the first cats brought down prey by stabbing it with long canine teeth. In order to snag its prey this way, early cats were able to open their mouths further. The zygomatic arch on the side of the skull was shorter, making the temporalis muscle on the side of the jaw less massive. Since a saber-tooth tiger with a broken canine could not be a successful hunter, the 7-inch canine became shorter as the species evolved. As cats got smaller, stabbing prey became less of an option, and the cat developed an ability to crush its victim's windpipe or tear open its throat in order to subdue it. This called for a strong bite and a short nose, which is just how Miss Kitty comes to us today. Cats today still need to hunt and subdue, which is why they are given toys to chase and bite.