Many shark behaviours have a communication function, often in relation to social hierarchies. Many sharks eat other shark species, as well as members of their own species, and therefore social hierarchies, which are often size dependent, serve as anti-predatory tactics on the part of subordinate sharks. For example, white sharks dominate blue sharks when feeding on a whale carcass. Blue sharks will not scavenge until the white shark is finished.
For the most part, the behaviour of sharks is unknown; however, we are slowly filling in the gaps. There is a considerable wealth of existing knowledge that attempts to explain shark behaviour.