Cockfighting falls into a category of sporting activities known as blood sports and it dates back several centuries to ancient Asia.
Two roosters, known as "gamecocks" that are usually trained to battle, face off until either one of the birds has died, or one of them refuses to fight any more.
Roosters are very aggressive, especially towards males of the same species.
The roosters fight in a walled pit and are accompanied by their handlers and a referee.
In some fights, birds are outfitted with weapons on their legs that can be called gaffs, cockspurs or knives. In other fights, known as peck fights, the birds do not have extra weapons.
In many countries, cockfighting is illegal and considered cruel to animals.
Common terms that have come from this sport include "the pecking order," "cocky" and "cockpit."