Bulls can often be fierce and dangerous, especially in the presence of their herd of cows and heifers. In the wild, they will often fight each other over mating rights and their herds of cows and will use their horns to "gore" each other. Some bulls will fight to the death: others will fight until either one of the bulls decides to run off. They also protect the herds from other animals such as wolves, jackals, bears, tigers and lions. On farms, bulls are usually quieter and more docile and can be led by a nose-ring by their owners, but they can be aggressive with other bulls and with strange people or animals who might get too near his herd. Dairy bulls like Jerseys and Holsteins tend to be more aggressive than bulls of beef breeds like Hereford and Angus. Not all cattle have horns. Bulls with no horns fight by head-butting the other's head, neck, side or belly, and will use their heads to push each other around. 