The word “Spain” often brings upon an image of a handsome matador taunting a fierce bull with his red cape. Because of this, it is commonly thought that the colour red aggravates bulls, and this is often used in cartoons.
However, as bulls are colour blind, they cannot tell a red cape apart from a blue cape. They are actually responding to the movement of the cape and being provoked by the matador. Furthermore, the bulls used in bullfights tend to be a more aggressive breed. This type of charging behaviour is common in large herbivores such as hippos, rhinos and elephants, as it is very useful in nature when faced with a predator.
Also, the real reason the cape is red is not only because it symbolises passion and power, but because it also hides the blood from the bull during the fight.