Crocodiles and alligators have a maximum biting force of 2000 psi (that’s more than 10 times the pressure in your bike tire) that allows them to snap their jaws to capture their prey, yet they are also gentle enough to carry their young in their mouths. They must have some way to sense or control the amount of force they use.
One clue is found in a strange feature of crocodiles and alligators. A way to distinguish between different specimens is by examining the pattern of spots that cover the head in alligators and head and body in crocodiles. Until now, no one really knew the purpose of these unusual bumps.
Recently, a paper was published in the Journal of Experimental Biology that determined that the spots are like tiny, extremely sensitive pressure sensors. These special adaptations are even more sensitive than human fingers!
The researchers believe that this pressure sensing allows the animals to respond to nearby fluctuations that signal the presence of prey. Once they have reached the prey, the sensors allow them to determine whether it really is something tasty to eat or just a hard rock. Thus, it also may provide an answer to how the animals know how hard to bite.
If you ever cross a croc remember – freeze!
Movie of crocodiles and alligators sensing: http://jeb.biologists.org/content/suppl/2012/11/05/215.23.4217.DC1/Movie1.mov