There are many myths surrounding crocodilians. Some are rather far fetched, born from fear of the unknown blown out of proportion as stories are retold. Some myths are not far from fact, the reality simply misunderstood.
One such myth we hear regularly is that crocs can’t bite underwater because they can’t open their mouths underwater. This is obviously not true as most species of crocodilians hunt and eat fish as a large part of their diet, but it’s easy to see where this myth originated.
Crocodilians cannot swallow anything of decent size with their heads submerged. When you see crocs swallow prey, they lift their whole head above the water. The reason for this is because of a flap of skin called a palatial valve which prevents water going down their throat. With the palatal valve in place, crocs can hunt underwater and catch prey, or hold prey in their open mouth without fear of drowning.