The game on the field is regulated by the two umpires, one of whom stands behind the wicket at the bowler's end, the other in a position called "square leg" which is about 15–20 metres away from the batsman on strike and in line with the popping crease on which he is taking guard. The umpires have several responsibilities including adjudication on whether a ball has been correctly bowled (i.e., not a no-ball or a wide); when a run is scored; whether a batsman is out (the fielding side must first appeal to the umpire, usually with the phrase "How's that?" or "Owzat?"); when intervals start and end; and the suitability of the pitch, field and weather for playing the game. The umpires are authorised to interrupt or even abandon a match due to circumstances likely to endanger the players, such as a damp pitch or deterioration of the light.
If the match has only a single innings per side, then a maximum number of overs applies to each innings. Such a match is called a "limited overs" or "one-day" match, and the side scoring more runs wins regardless of the number of wickets lost, so that a draw cannot occur. If this kind of match is temporarily interrupted by bad weather, then a complex mathematical formula, known as the Duckworth-Lewis method after its developers, is often used to recalculate a new target score. A one-day match can also be declared a "no-result" if fewer than a previously agreed number of overs have been bowled by either team, in circumstances that make normal resumption of play impossible; for example, wet weather.
Some species of cricket are polyandrous. In Gryllus bimaculatus, the females select and mate with multiple viable sperm donors, preferring novel mates. Female Teleogryllus oceanicus crickets from natural populations similarly mate and store sperm from multiple males. Female crickets exert a postcopulatory fertilization bias in favour of unrelated males to avoid the genetic consequences of inbreeding. Fertilization bias depends on the control of sperm transport to the sperm storage organs. The inhibition of sperm storage by female crickets can act as a form of cryptic female choice to avoid the severe negative effects of inbreeding. Controlled-breeding experiments with the cricket Gryllus firmus demonstrated inbreeding depression, as nymphal weight and early fecundity declined substantially over the generations' this was caused as expected by an increased frequency of homozygous combinations of deleterious recessive alleles.
Cricket is a bat-and-ball game played on a cricket field (see image, right) between two teams of eleven players each. The field is usually circular or oval in shape and the edge of the playing area is marked by a boundary, which may be a fence, part of the stands, a rope, a painted line or a combination of these; the boundary must if possible be marked along its entire length.
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".
A phylogenetic study by Jost & Shaw in 2006 using sequences from 18S, 28S, and 16S rRNA supported the monophyly of Ensifera. Most ensiferan families were also found to be monophyletic, and the superfamily Gryllacridoidea was found to include Stenopelmatidae, Anostostomatidae, Gryllacrididae and Lezina. Schizodactylidae and Grylloidea were shown to be sister taxa, and Rhaphidophoridae and Tettigoniidae were found to be more closely related to Grylloidea than had previously been thought. The authors stated that "a high degree of conflict exists between the molecular and morphological data, possibly indicating that much homoplasy is present in Ensifera, particularly in acoustic structures." They considered that tegmen stridulation and tibial tympanae are ancestral to Ensifera and have been lost on multiple occasions, especially within the Gryllidae.
Crickets have a cosmopolitan distribution, being found in all parts of the world with the exception of cold regions at latitudes higher than about 55° North and South. They have colonised many large and small islands, sometimes flying over the sea to reach these locations, or perhaps conveyed on floating timber or by human activity. The greatest diversity occurs in tropical locations, such as in Malaysia, where 88 species were heard chirping from a single location near Kuala Lumpur. A greater number than this could have been present because some species are mute.
Cricket entered a new era in 1963 when English counties introduced the limited overs variant. As it was sure to produce a result, limited overs cricket was lucrative and the number of matches increased. The first Limited Overs International was played in 1971 and the governing International Cricket Council (ICC), seeing its potential, staged the first limited overs Cricket World Cup in 1975. In the 21st century, a new limited overs form, Twenty20, made an immediate impact. On 22 June 2017, Afghanistan and Ireland became the 11th and 12th ICC full members, enabling them to play Test cricket.
The wicket-keeper (sometimes called simply the "keeper") is a specialist fielder subject to various rules within the Laws about his equipment and demeanour. He is the only member of the fielding side who can effect a stumping and is the only one permitted to wear gloves and external leg guards. Depending on their primary skills, the other ten players in the team tend to be classified as specialist batsmen or specialist bowlers. Generally, a team will include five or six specialist batsmen and four or five specialist bowlers, plus the wicket-keeper.
Off the field in televised matches, there is usually a third umpire who can make decisions on certain incidents with the aid of video evidence. The third umpire is mandatory under the playing conditions for Test and Limited Overs International matches played between two ICC full member countries. These matches also have a match referee whose job is to ensure that play is within the Laws and the spirit of the game.
In 1611, the year Cotgrave's dictionary was published, ecclesiastical court records at Sidlesham in Sussex state that two parishioners, Bartholomew Wyatt and Richard Latter, failed to attend church on Easter Sunday because they were playing cricket. They were fined 12d each and ordered to do penance. This is the earliest mention of adult participation in cricket and it was around the same time that the earliest known organised inter-parish or village match was played – at Chevening, Kent. In 1624, a player called Jasper Vinall died after he was accidentally struck on the head during a match between two parish teams in Sussex.
The innings (ending with 's' in both singular and plural form) is the term used for each phase of play during a match. Depending on the type of match being played, each team has either one or two innings. Sometimes all eleven members of the batting side take a turn to bat but, for various reasons, an innings can end before they have all done so. The innings terminates if the batting team is "all out", a term defined by the Laws: "at the fall of a wicket or the retirement of a batsman, further balls remain to be bowled but no further batsman is available to come in". In this situation, one of the batsmen has not been dismissed and is termed not out; this is because he has no partners left and there must always be two active batsmen while the innings is in progress.
The folklore and mythology surrounding crickets is extensive. The singing of crickets in the folklore of Brazil and elsewhere is sometimes taken to be a sign of impending rain, or of a financial windfall. In Álvar Núñez Cabeza de Vaca's chronicles of the Spanish conquest of the Americas, the sudden chirping of a cricket heralded the sighting of land for his crew, just as their water supply had run out. In Caraguatatuba, Brazil, a black cricket in a room is said to portend illness; a gray one, money; and a green one, hope. In Alagoas state, northeast Brazil, a cricket announces death, thus it is killed if it chirps in a house. In Barbados, a loud cricket means money is coming in; hence, a cricket must not be killed or evicted if it chirps inside a house. However, another type of cricket that is less noisy forebodes illness or death.
There are various formats ranging from Twenty20, played over a few hours with each team batting for a single innings of 20 overs, to Test matches, played over five days with unlimited overs and the teams each batting for two innings of unlimited length. Traditionally cricketers play in all-white kit, but in limited overs cricket they wear club or team colours. In addition to the basic kit, some players wear protective gear to prevent injury caused by the ball, which is a hard, solid spheroid made of compressed leather with a slightly raised sewn seam enclosing a cork core which is layered with tightly wound string.