The diet of hatchling, juvenile and subadult saltwater crocodiles has been subject to extensively greater scientific study than that of fully-grown crocodiles, in large part due to the aggression, territoriality and size of adults which make them difficult for biologists to handle without significant risk to safety, for both humans and the crocodiles themselves; the main method used for capturing adult saltwater crocodiles is a huge pole with large hooks meant for shark capture which restrict the crocodile's jaws but can cause damage to their snouts and even this is unproven to allow successful capture for crocodiles in excess of 4 meters .