Does the color red really make bulls angry? Spanish matadors began using a small red cape, or muleta, in bullfighting around the 1700s. Ever since, it seems, people have perpetuated the color-charged myth that red makes bulls go wild.The color red isn't what causes bulls to attack. In fact, bulls don't seem to have any color preference at all. They'll charge whichever object is moving the most, which means this old myth can get tossed right out of the ring.