The color red makes bulls aggressive
The much-believed premise behind bullfighting is that the red cape gets the bull revved up and makes him charge at the matador. In reality, cattle are dichromatic (colorblind) and don’t see red as a vivid color. What they are responding to is the movement of the cape and the overall threat of the situation. (We don’t blame them, we’d be mad too.)
On a happier note, pictured here is Spanish torero Jose Tomas during the last bullfight in Catalonia before the government prohibition of bullfighting took place in 2011.