The long-standing belief that bulls become enraged by the color red is a widespread misconception. This idea, deeply ingrained in popular culture, particularly due to bullfighting imagery, does not align with scientific understanding. Bulls do not react to the color red itself; their aggressive responses are triggered by other factors.
The Myth of Color Perception
Bulls possess dichromatic vision. This means their eyes have two types of cone cells for color detection, unlike humans who have three. Bulls lack the cone receptor sensitive to red light, making them red-green colorblind. A red object would likely appear to them as a shade of yellowish-gray or dull brown.
Their visual system is more attuned to detecting movement and variations in brightness rather than specific hues. Research, including experiments like those conducted by the Discovery Channel’s “MythBusters,” has demonstrated that bulls charge at moving objects regardless of their color. This indicates that the color red is not inherently provocative to them.
Factors That Trigger Aggression
A bull’s aggressive behavior stems from a combination of natural instincts and responses to perceived threats. Rapid or erratic movement is a primary trigger for their charges. Any sudden, unpredictable motion can be interpreted by a bull as a challenge or an incoming threat, prompting a defensive fight-or-flight response.
Beyond movement, factors such as stress, agitation, and territorial instincts play a significant role in a bull’s aggression. Bulls are powerful animals, and if they feel cornered, threatened, or perceive an intrusion into their space, they may react with force. Hormonal influences, particularly testosterone, also contribute to their temperament, especially during breeding seasons.
The Matador’s Cape
Despite bulls being unable to distinguish red, the cape (muleta) used in bullfighting is traditionally red. This choice is not for the bull’s perception but for human tradition and practical reasons. The movement of the cape, not its color, is what attracts the bull’s attention and provokes its charge. The matador’s skill lies in using the cape’s motion to direct the bull, creating a dramatic spectacle.
The red color also serves to mask bloodstains that may occur during the bullfight, making the event less graphic for the audience. Therefore, while the red cape is iconic to bullfighting, its color is primarily for the human audience and tradition rather than inciting aggression in the bull itself.