Bulls charge at bullfighters because they’re irritated by the flapping of the cape, not because the cape is red. In fact, they can’t even see the color red. Cattle are colorblind. The bull would charge at any flapping fabric that was irritating it, regardless of the color. Basically, what bulls react to is movement.

Bulls are known to become agitated and charge at the sight of the color red. This seemingly strange behavior has its roots in bull biology and psychology. Understanding why bulls react to red helps explain their behavior and the role this plays in bullfighting and rodeo sports involving bulls.

The charging behavior is a key element of the traditional bullfighting spectacle, where the matador (bullfighter) uses the cape to engage with the bull. The basic reasons why a bull charges at a red cape are the following: Provocation and stimulation Movement and visual stimuli Conditioning and training Reinforcement and reinforcement removal