“The color red makes bulls angry and causes them to charge”

It's a common scene in popular culture and bullfighting arenas: a matador waves a vibrant red cape, and the bull charges furiously. This imagery has ingrained the belief that the color red enrages bulls, leading to the widespread misconception that scarlet hues are a visual trigger for aggression in these powerful animals. This myth largely originates from the spectacle of bullfighting itself, where the red muleta is a central prop.

However, scientific evidence busts this long-held belief. Cattle, including bulls, are dichromatic, meaning their vision differs significantly from humans'. They are largely red-green colorblind, perceiving these colors as shades of gray or yellow. Therefore, a bull cannot distinguish a red cape from a green, blue, or white one. What truly provokes a bull to charge is movement. The matador's sweeping and flapping of the cape, regardless of its color, is what catches the bull's attention and instigates the charge.

The tradition of using a red cape in bullfighting isn't for the bull's benefit, but for the audience and practical reasons. The deep red color of the muleta serves to mask bloodstains that may occur during the fight, maintaining a more aesthetically pleasing appearance for spectators. It also adds a dramatic visual element to the performance. When tested with various colored capes held still, bulls show no preference for charging at red over any other color, further confirming that it is the motion, not the hue, that stimulates their response.