Previous versions of the Spirit identified actions that were deemed contrary (for example, appealing knowing that the batsman is not out) but all specifics are now covered in the Laws of Cricket, the relevant governing playing regulations and disciplinary codes, or left to the judgement of the umpires, captains, their clubs and governing bodies. The terse expression of the Spirit of Cricket now avoids the diversity of cultural conventions that exist in the detail of sportsmanship – or its absence.
Crickets chirp at different rates depending on their species and the temperature of their environment. Most species chirp at higher rates the higher the temperature is (about 62 chirps a minute at 13 °C (55 °F) in one common species; each species has its own rate). The relationship between temperature and the rate of chirping is known as Dolbear's law. According to this law, counting the number of chirps produced in 14 seconds by the snowy tree cricket, common in the United States, and adding 40 will approximate the temperature in degrees Fahrenheit.
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.
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.
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.
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".
Captive crickets are omnivorous; when deprived of their natural diet, they accept a wide range of organic foodstuffs. Some species are completely herbivorous, feeding on flowers, fruit, and leaves, with ground-based species consuming seedlings, grasses, pieces of leaf, and the shoots of young plants. Others are more predatory and include in their diet invertebrate eggs, larvae, pupae, moulting insects, scale insects, and aphids. Many are scavengers and consume various organic remains, decaying plants, seedlings, and fungi. In captivity, many species have been successfully reared on a diet of ground, commercial dry dog food, supplemented with lettuce and aphids.