While the umpire (1) in shot stands at the bowler's end of the pitch, his colleague stands in the outfield, usually in or near the fielding position called "square leg", so that he is in line with the popping crease (7) at the striker's end of the pitch. The bowling crease (not numbered) is the one on which the wicket is located between the return creases (12). The bowler (4) intends to hit the wicket (9) with the ball (5) or, at least, to prevent the striker (8) from scoring runs. The striker (8) intends, by using his bat, to defend his wicket and, if possible, to hit the ball away from the pitch in order to score runs.
Gryllus firmus exhibits wing polymorphism; some individuals have fully functional, long hind wings and others have short wings and cannot fly. The short-winged females have smaller flight muscles, greater ovarian development, and produce more eggs, so the polymorphism adapts the cricket for either dispersal or reproduction. In some long-winged individuals, the flight muscles deteriorate during adulthood and the insect's reproductive capabilities improve.
Red parasitic mites sometimes attach themselves to the dorsal region of crickets and may greatly affect them. The horsehair worm Paragordius varius is an internal parasite and can control the behaviour of its cricket host and cause it to enter water, where the parasite continues its lifecycle and the cricket likely drowns. The larvae of the sarcophagid fly Sarcophaga kellyi develop inside the body cavity of field crickets. Female parasitic wasps of Rhopalosoma lay their eggs on crickets, and their developing larvae gradually devour their hosts. Other wasps in the family Scelionidae are egg parasitoids, seeking out batches of eggs laid by crickets in plant tissues in which to insert their eggs.
It is generally believed that cricket originated as a children's game in the south-eastern counties of England, sometime during the medieval period. Although there are claims for prior dates, the earliest definite reference to cricket being played comes from evidence given at a court case in Guildford on Monday, 17 January 1597 (Julian calendar; equating to 30 January 1598 in the Gregorian calendar). The case concerned ownership of a certain plot of land and the court heard the testimony of a 59-year-old coroner, John Derrick, who gave witness that:
The most famous player of the 19th century was W. G. Grace, who started his long and influential career in 1865. It was especially during the career of Grace that the distinction between amateurs and professionals became blurred by the existence of players like him who were nominally amateur but, in terms of their financial gain, de facto professional. Grace himself was said to have been paid more money for playing cricket than any professional.
As illustrated above, the pitch is marked at each end with four white painted lines: a bowling crease, a popping crease and two return creases. The three stumps are aligned centrally on the bowling crease, which is eight feet eight inches long. The popping crease is drawn four feet in front of the bowling crease and parallel to it; although it is drawn as a twelve-foot line (six feet either side of the wicket), it is, in fact, unlimited in length. The return creases are drawn at right angles to the popping crease so that they intersect the ends of the bowling crease; each return crease is drawn as an eight-foot line, so that it extends four feet behind the bowling crease, but is also, in fact, unlimited in length.
Subject to certain variations, on-field clothing generally includes a collared shirt with short or long sleeves; long trousers; woolen pullover (if needed); cricket cap (for fielding) or a safety helmet; and spiked shoes or boots to increase traction. The kit is traditionally all white and this remains the case in Test and first-class cricket but, in limited overs cricket, team colours are worn instead.
At the grassroots level, local club cricket is essentially an amateur pastime for those involved but still usually involves teams playing in competitions at weekends or in the evening. Schools cricket, first known in southern England in the 17th century, has a similar scenario and both are widely played in the countries where cricket is popular. Although there can be variations in game format, compared with professional cricket, the Laws are always observed and club/school matches are therefore formal and competitive events. The sport has numerous informal variants such as French cricket.
Crickets have many natural enemies and are subject to various pathogens and parasites. They are eaten by large numbers of vertebrate and invertebrate predators and their hard parts are often found during the examination of animal intestines. Mediterranean house geckos (Hemidactylus turcicus) have learned that although a calling decorated cricket (Gryllodes supplicans) may be safely positioned in an out-of-reach burrow, female crickets attracted to the call can be intercepted and eaten.
Given Derrick's age, it was about half a century earlier when he was at school and so it is certain that cricket was being played c. 1550 by boys in Surrey. The view that it was originally a children's game is reinforced by Randle Cotgrave's 1611 English-French dictionary in which he defined the noun "crosse" as "the crooked staff wherewith boys play at cricket" and the verb form "crosser" as "to play at cricket".
The match details, including runs and dismissals, are recorded by two official scorers, one representing each team. The scorers are directed by the hand signals of an umpire (see image, right). For example, the umpire raises a forefinger to signal that the batsman is out (has been dismissed); he raises both arms above his head if the batsman has hit the ball for six runs. The scorers are required by the Laws to record all runs scored, wickets taken and overs bowled; in practice, they also note significant amounts of additional data relating to the game.
If a fielder is injured or becomes ill during a match, a substitute is allowed to field instead of him, but the substitute cannot bowl or act as a captain. The substitute leaves the field when the injured player is fit to return. The Laws of Cricket were updated in 2017 to allow substitutes to act as wicket-keepers, a situation that first occurred when Mumbai Indians' wicket-keeper Ishan Kishan was injured in a match on 18 April 2018.