why does a crocodile open its mouth?

Answer 1

Alligators and crocodiles gape as a means to lower body temperature without going back into the water. They cannot stick out their tongues and pant like a dog, so they sit with their mouth propped open and it has the same effect.

Their mouth drying out from this is merely an effect of evaporation being used to cool themselves. This may aid in loosening any leeches or other parasites in their mouth, but is not the main reason.

Also, most prey items are smart enough to avoid a crocodilian with it's mouth open.

A study was conducted by the University of Florida a few years back. They made a hydraulic bitemeter and took it to the St. Augustine Alligator farm. What they found out, was that an average adult alligator giving a simple "get away from me" type bite, closes it's jaws at 2000 psi. When used on one of their largest alligators that they had really ticked off, the bitemeter broke. It was built to withstand up to 5000 psi.

And no. Two fingers will NOT hold an alligator or crocodile's mouth shut unless it is a small one. And even if it would, you still have the rest of the body to deal with.

Answer 2

a crocodile unlike humans is a cold blooded animal, so when its regulating its body temperatures it opens its mouth as the mouth has a bunch of blood vessels...

also a crocodile will probably like to keep its mouth open in order to kill its prey

a crocodile's jaw muscles are strong enough to close the jaw with the force of 2500 pounds but you can use just 2 fingers and keep it closed as it does not have a powerful opening mechanism

Answer 3

to give warning hisses ,
and
to dry its mouth out ,
its a form of cleaning
and to cool down ,
also it is ready to grab anything
a crocodile is like a trap
something get in it and bamm ,it is closed with a tremendous force
40 pounds for an adult crocodile

Answer 4

It's a play behavior. I've listed a link that explains it to a point.