Fighting bulls are characterized by their aggressive behaviour, especially when solitary or unable to flee. Many are coloured black or dark brown, but other colours are normal. They reach maturity more slowly than meat breeds as they were not selected to be heavy, having instead a well-muscled "athletic" look, with a prominent
morrillo, a complex of muscles over the shoulder and neck which gives the bull its distinctive profile and strength with its horns. The horns are longer than in most other breeds and are present in both males and females. Mature bulls weigh from . Among fighting cattle, there are several "encastes" or subtypes of the breed. Of the so-called "foundational breeds", only the bloodlines of Vistahermosa, Vázquez, Gallardo and Cabrera remain today. In the cases of the last two only the ranches of
Miura and Pablo Romero are deeply influenced by them. The so-called "modern foundational bloodlines" are Saltillo, Murube, Parladé and Santa Coloma, all of which are primarily composed of Vistahermosa blood. Cattle have
dichromatic vision, rendering them red-green colourblind and falsifying the idea that the colour red makes them angry; they just respond to the movements of the
muleta. The red colouring is traditional and is believed to both conceal blood stains and provide a suitable light-dark contrast against the arena floor.
Growth . Fighting cattle are bred on wide-ranging ranches in Spain's
dehesas or in the Portuguese Montados, which are often havens for Iberian wildlife as the farming techniques used are extensive. Both male and female calves spend their first year of life with their mothers; then they are weaned,
branded, and kept in single-sex groups. When the cattle reach maturity after two years or so, they are sent to the
tienta, or testing. For the males, this establishes if they are suitable for breeding, the bullfight, or slaughter for meat. The testing for the
bullfight is only of their aggression towards the horse, as regulations forbid their charging a man on the ground before they enter the bullfighting ring. They learn how to use their horns in tests of strength and dominance with other bulls. Due to their special aggression, these combats can lead to severe injuries and even death of the bulls, at great cost to their breeders. The females are more thoroughly tested, including by a bullfighter with his capes; hence a bull's "courage" is often said to descend from his mother. If fit for bullfighting, bulls will return to their peers. Cows passing the tienta are kept for breeding and will be slaughtered only when they can bear no more calves. At three years old males are no longer considered calves; they are known as
novillos and are ready for bullfighting, although
novilladas are for training bullfighters, or
novilleros. The best bulls are kept for
corridas de toros with full
matadors. Under Spanish law they must be at least four years old and reach the weight of 460 kg to fight in a first-rank bullring, 435 kg for a second-rank one, and 410 kg for third-rank rings. They must also have fully functional vision and horns that are even (and have not been tampered with) and be in generally good condition. A very few times each year a bull will be
indultado, or "pardoned", meaning his life is spared due to outstanding behaviour in the bullring, leading the audience to petition the president of the ring with white handkerchiefs. The bullfighter joins the petition, as it is a great honour to have a bull one has fought pardoned. The president pardons the bull showing an orange handkerchief. The bull, if he survives his injuries, which are usually severe, is then returned to the ranch he was bred at, where he will live out his days in the fields. In most cases, he will become a "seed bull", mated once with some 30 cows. Four years later, his offspring will be tested in the ring. If they fight well, he may be bred again. An "indultado" bull's lifespan can be 20 to 25 years. ==Miura==