Mastiff: 556 Pounds per Square InchIn the wild, Spotted/Striped Hyenas (which eat bones) can clampw at 1100 PSI,
Rottweiler: 328 PSI
German Shepherd: 238 PSI
American Pitbull: 235
Saltwater crocodiles, at 7700 PSI, have the most powerful jaws of any living creature (including tigers, rhinos, grizzlies and sharks) but their jaw opening muscles are quite weak, which is why the crazed humans who wrestle them try to lock down their jaws — not hard to do, if you can ride out the thrashing.