Yet the muscles that open the jaws have little strength. For example, a rubber band around the snout of a 2 m long crocodilian is sufficient to prevent it opening its mouth.
The crocodile jaw has very little opening strength, though; a crocodile's mouth can be held shut with just a rubber band. In addition to their strong jaws, crocodiles have very keen hearing.
The jaws can easily be held shut with a hand, but it is safer to use an elastic band, masking / duct tape or some other kind of fabric loop - otherwise a struggling animal can slice through your flesh with its sharp teeth which project above and below the jaw-line even with the mouth shut.
The palatal valve is present in all species and plays an essential role in preventing water in the mouth from entering the throat, oesophagus and trachea when the crocodile is underwater. This enables the crocodile to open its mouth at any time underwater (see right), and is particularly useful during prey capture.
Unfortunately, a croc's jaw has so much power that once it's locked, no amount of struggling will get it back open. Trying to pry a croc's mouth open with your hands won't work.
It can exert 3,700 pounds per square inch of force, which is more than thirty times that of a human bite” [1]. According to Science Daily, crocodiles have likely retained this ability since the Mesozoic Era, when dinosaurs roamed the earth].
An average crocodile that weighs 700 pounds and measures over 10 feet long is going to be too powerful for a human to overcome.
Crocodile's tongue
Crocodiles have a membrane that holds their tongue in place on the roof of their mouth so it doesn't move. This makes it impossible for them to stick it outside of their narrow mouths. That can be handy for the reptile when snapping its jaws shut rapidly.
The "winners"—saltwater crocodiles—slammed their jaws shut with 3,700 pounds per square inch (psi), or 16,460 newtons, of bite force. By contrast, you might tear into a steak with 150 to 200 psi (890 newtons).
Crocodiles cannot bite underwater
They have a palatal valve that seals off the back of the mouth/throat, preventing water entering the lungs when underwater.
Their jaws close with tremendous force and sink into prey with tons of pressure (alligator = 2,980 psi [pounds per square inch] — Crocodile = 5,000 psi), but the muscles that open the jaws are weak.
The muscles that engage their jaw gives them one of the most powerful bites in the animal world. Once their jaw is shut, they will lock that position and crush any unfortunate animals that they're preying on.
With its jaw back open, that is your chance to escape. "Alligators clamp down with powerful jaws, then twist and roll. If an alligator bites your arm, it may help to grab the alligator and roll with it to reduce tearing of the arm," according to advice from the South Carolina Department of Natural Resources.
Crocodilians, including the alligator (Alligator mississippiensis), perform a spinning maneuver to subdue and dismember prey. The spinning maneuver, which is referred to as the ;death roll', involves rapid rotation about the longitudinal axis of the body.
“They are messy eaters.” After latching onto an animal and drowning it, a crocodile will dismember its victim into “bite-size” pieces by rolling it underwater, violently shaking the carcass, and banging it on rocks, marking and fracturing the bones in the process.
The researchers found that crocs and gators can snap their jaws shut around prey within 50 milliseconds, a reaction time likely enabled by their super-sensitive skin.
In the wild, an older, weaker croc is more likely to face starvation or competition, but even in captivity, the animals inevitably die.
Crocodiles' skin is tough, thick, and bony, but they are not bulletproof. They may be able to fend off low-caliber bullets, but that doesn't necessarily make them bulletproof.
American Alligators have a bite force of about 2125 PSI. And the strongest known bite force of the entire animal kingdom is…. The Crocodile -- specifically, the Saltwater Crocodile (the highest recorded “live” bite of 3700 PSI) and the Nile Crocodile (estimated 4000-5000 PSI)!
"If they've got hold of you, poking the eyes is the only possible way you can fight back - they have thousands of years of instinct telling them this is the only vulnerable part of their body and they need to let go," Mr Cooper says.
A crocodile can't stick its tongue out.
Professor Secor said the experiment had been carried out to show that a python could easily digest an alligator, which had been killed prior to being fed to the python. Although relatively small in this case, Burmese pythons have been known to take on much larger alligators and crocodiles.
But how quickly can they run? Most crocodiles can achieve speeds of around 12 to 14 kph for short periods, which is somewhat slower than a fit human can run. Don't believe the hype - if you're reasonably fit, you can definitely outrun a crocodile!
Australia has a large population of crocodiles but as the research noted, there are only an average of 1.9 attacks a year.