This defense mechanism will asphyxiate the larger creature. The great squid and salt-water crocodile are both fierce shark hunters. The killer whale has been seen to swallow a shark whole. While dolphins and sharks have been known to coexist peacefully, a dolphin can efficiently dispose of a shark. One technique of the dolphin is to swim full-speed towards the abdomen of the shark, smacking into this tender area and causing the shark s delicate intestines to hemorrhage.
Dolphins also bump into the gills of the shark, which destroys the shark s ability to breathe.
In one case, there was an aquarium where a shark and several dolphins had been living together without difficulty for some time when the dolphins, for unknown reasons, threw the shark out 20 feet away onto the floor. For man, only approximately 10 percent of sharks are dangerous. However, there are no known infallible shark repellents. In order to be effective, a shark repellent must work before the shark attacks, as nothing short of death will deter a shark once it has begun its run. The perfect shark repellent must be effective against all species of sharks suspected of being dangerous to man.