The misconception that bulls are provoked by the color red likely originates from bullfighting practices in some cultures where the matador waves a red cape or muleta to provoke the bull. However, the red color itself is not the main trigger for the bull's aggression.

Bulls, along with all other cattle, are color-blind to red. Thus, the bull is likely irritated not by the muleta ’s color, but by the cape’s movement as the matador whips it around. In support of this is the fact that a bull charges the matador’s other cape — the larger capote — with equal fury.

The idea that bulls are angered by the color red is a common misconception. Bulls are actually color-blind to the color red and green. The reason why they react aggressively towards matadors’ red capes is due to the movement of the cape, not the color. Bulls naturally charge towards movement, especially when they feel threatened.

The reason why red couldn’t possibly be what makes bulls angry is that they can’t even see the color, since their eyes lack L-cones – the cone cells associated with detecting the color red. This lack of L-cones makes bulls dichromatic creatures, and it causes them to have trouble differentiating red from green.