bull

A bull is a male bovine animal, typically of domestic cattle (Bos taurus). The term is generally reserved for sexually mature males; a female is a cow, and a castrated male used for work or beef is a steer or ox. Bulls are also designated for adult males of other bovine species, such as buffalo or zebu, when discussed in a cattle context.

Bulls are usually larger and more muscular than cows, with horns on many breeds. Coat color and patterns vary widely. They are social animals with a herd structure; bulls may form bachelor groups or guard breeding herds. They can be territorial and may exhibit aggressive behavior, particularly during the rut or breeding season.

Maturity occurs around 12 to 18 months; breeding occurs through natural mating; gestation is about 280-290 days; calves are born and raised by the cow. Bulls kept for breeding contribute to genetic selection via the offspring they sire; many breeding programs rely on artificial insemination using semen collected from bulls rather than keeping every bull in a herd.

In agriculture, bulls are used for breeding and, in some systems, for meat or draft work when not castrated; most beef production, however, relies on steers and heifers. Bulls participate in cultural activities such as bullfighting in some regions, and appear as symbols in heraldry and in financial markets where a rising market is described as bullish.

Domestic cattle descend from wild aurochs (Bos primigenius); modern bulls show wide variation across breeds in size, horn shape, and temperament.