The gestation period of queens is between 64 and 67 days, with an average of 66 days. Data on reproductive capacity of more than 2,300 free-ranging queens were collected during a study between May 1998 and October 2000. They had one to six kittens per litter, with an average of three kittens. They produced a mean of 1.4 litters per year, but a maximum of three litters in a year. Of 169 kittens, 127 died before they were six months old due to a trauma caused in most cases by dog attacks and road accidents. The first litter is usually smaller than subsequent litters. Kittens are weaned between six and seven weeks of age. Queens normally reach sexual maturity at 5–10 months, and males at 5–7 months. This varies depending on breed.
The Late Latin word is generally thought to originate from an Afro-Asiatic language, but every proposed source word has presented problems. Many references refer to "Berber" (Kabyle) kaddîska, 'wildcat', and Nubian kadīs as possible sources or cognates, but M. Lionel Bender suggests the Nubian term is a loan from Arabic قِطَّة qiṭṭa. Jean-Paul Savignac suggests the Latin word is from an Ancient Egyptian precursor of Coptic ϣⲁⲩ šau, 'tomcat', or its feminine form suffixed with -t, but John Huehnergard says "the source [...] was clearly not Egyptian itself, where no analogous form is attested." Huehnergard opines it is "equally likely that the forms might derive from an ancient Germanic word, imported into Latin and thence to Greek and to Syriac and Arabic". Guus Kroonen also considers the word to be native to Germanic (due to morphological alternations) and Northern Europe, and suggests that it might ultimately be borrowed from Uralic, cf. Northern Sami gáđfi, 'female stoat', and Hungarian hölgy, 'stoat'; from Proto-Uralic *käďwä, 'female (of a furred animal)'. In any case, cat is a classic example of a word that has spread as a loanword among numerous languages and cultures: a Wanderwort.
Cats premiered in the West End at the New London Theatre on 11 May 1981. The musical was produced by Mackintosh and Lloyd Webber's Really Useful Group, with direction by Nunn, choreography by Lynne (who also served as the associate director), set and costume design by Napier, lighting design by David Hersey, sound design by Abe Jacob and music direction by Harry Rabinowitz. It played a total of 8,949 performances before closing on its 21st anniversary, 11 May 2002. The final performance was broadcast live on a large outdoor screen in Covent Garden for fans who could not acquire a ticket. Cats held the record as London's longest-running musical from 1989, when it surpassed Jesus Christ Superstar, until 8 October 2006, when it was surpassed by Les Misérables.
Serious damage is rare, as the fights are usually short in duration, with the loser running away with little more than a few scratches to the face and ears. However, fights for mating rights are typically more severe and injuries may include deep puncture wounds and lacerations. Normally, serious injuries from fighting are limited to infections of scratches and bites, though these can occasionally kill cats if untreated. In addition, bites are probably the main route of transmission of feline immunodeficiency virus. Sexually active males are usually involved in many fights during their lives, and often have decidedly battered faces with obvious scars and cuts to their ears and nose.
The origin of the English word cat (Old English catt) and its counterparts in other Germanic languages (such as German Katze), descended from Proto-Germanic *kattōn-, is controversial. It was thought traditionally to be a borrowing from Late Latin cattus, 'domestic cat', from catta (used around 75 AD by Martial), compare also Byzantine Greek κάττα, Portuguese and Spanish gato, French chat, Maltese qattus, Lithuanian katė, and Old Church Slavonic kotъ (kot'), among others.