Male crickets establish their dominance over each other by aggression. They start by lashing each other with their antennae and flaring their mandibles. Unless one retreats at this stage, they resort to grappling, at the same time each emitting calls that are quite unlike those uttered in other circumstances. When one achieves dominance, it sings loudly, while the loser remains silent.
Limited overs cricket is always scheduled for completion in a single day. There are two types: List A which normally allows fifty overs per team; and Twenty20 in which the teams have twenty overs each. Both of the limited overs forms are played internationally as Limited Overs Internationals (LOI) and Twenty20 Internationals (T20I). List A was introduced in England in the 1963 season as a knockout cup contested by the first-class county clubs. In 1969, a national league competition was established. The concept was gradually introduced to the other leading cricket countries and the first limited overs international was played in 1971. In 1975, the first Cricket World Cup took place in England. Twenty20 is a new variant of limited overs itself with the purpose being to complete the match within about three hours, usually in an evening session. The first Twenty20 World Championship was held in 2007. Limited overs matches cannot be drawn, although a tie is possible and an unfinished match is a "no result".