“Bulls are enraged by the color red”

The enduring image of a bull charging a matador's vibrant red cape is deeply ingrained in popular culture, leading many to believe that the color itself is what ignites the animal's fury (Review). This dramatic scene, central to bullfighting traditions, has inadvertently fueled a widespread misconception about bovine vision and temperament.

However, scientific evidence reveals that cattle, including bulls, are dichromatic. This means they possess only two types of cone cells in their eyes, unlike humans who have three. Consequently, bulls perceive the world in a spectrum of blues and yellows, making them unable to distinguish between red and green. Their reaction in the bullfighting arena is not to the hue of the cape, but rather to its sudden, sweeping movements. The matador's flourishes and the constant motion of the fabric are what agitate the animal, prompting it to charge.

This persistent myth largely stems from the visual spectacle of bullfighting itself. The vivid red cape, known as a muleta, is a powerful symbol within the tradition, designed to be visually striking for human spectators. Over centuries, the association of the red cape with the bull's aggressive charge led to the assumption that color was the direct cause, rather than merely an incidental characteristic of the moving object. It's a classic example of correlation being mistaken for causation, where a compelling visual narrative overshadows biological reality.