Nope! Bulls don’t actually hate the color red. In fact, they can’t even really see the color red. Bulls, like all other cattle, are colorblind to red. So why do they charge at a bullfighter’s red cape then?
Bullfighters, known as matadors, use a small red cape, called a muleta, during a bullfight. It appears that bulls get irritated by the cape’s movement, not its color. The television show Mythbusters tested this hypothesis during one of their shows.
Their tests showed that bulls had the same reaction to white capes and blue capes as they did to red capes. Moreover, their tests revealed that bulls only became interested and began charging the capes when they were moved around.
Since Spanish matadors have been using the muleta since the early 18th century, the association with bulls charging at the color red has stuck in people’s minds. In reality, though, the bull would charge at any waving muleta, regardless of its color.
So, if the color doesn’t make a difference to the bull, why are red muletas used? The answer has more to do with the audience than the bull. First, the ornate costumes and red capes are considered an important part of the culture and tradition of bullfighting. In the same way that sports teams always wear the same colors, the red capes are seen as part of the bullfighting uniform.
There’s also a practical reason for using red. While there are some non-lethal bullfights, in most cases the bull is killed by the matador in the end. The red color of the muleta thus helps to cover the sight of the bull’s blood.