“Bulls are enraged by the color red.”

It's a widely held belief that the color red sends bulls into a furious rage, causing them to charge aggressively. However, this popular notion is a classic misconception. The truth is that bulls, like many other mammals, are dichromatic, meaning they are largely colorblind to red and green hues. Their vision is more akin to a human with red-green colorblindness, perceiving these colors as shades of grey or yellow.

The aggressive reaction seen in bullfights, which often fuels this myth, is not triggered by the vibrant crimson of the matador's cape. Instead, it is the erratic and sudden movement of the fabric that agitates the animal. A bull's vision is highly sensitive to motion, and the dramatic waving and flapping of the cape, regardless of its color, are what provoke its charge. If the matador were to stand still with a red cape, the bull would likely remain calm, but any sudden movement, even with a white or blue cape, would elicit the same aggressive response.

This enduring myth likely stems from the long-standing tradition of using red capes in bullfighting. The deep red color serves a practical purpose for the human spectators and participants, as it effectively disguises bloodstains that may occur during the fight, making the spectacle more palatable. Over time, the visual association of the red cape with the bull's charge led many to incorrectly assume a causal link between the color and the animal's temperament, solidifying a belief that science has long since disproven.