Fact:

One of the most common myth-conceptions around the world is that bulls are intimidated by the color red. In reality, however, chances are the bulls are more infuriated by the ridiculous costumes that matadors wear than the actual color of the capes. Why is that? The reason is that bulls are color blind.

An approximate number of 250,000 bulls are tragically murdered each year in bullfights (PETA). The ritual of the famous Spanish bullfights begins with a swinging act by the matador holding a red cape in front of the bull. The bulls immediately start running after the matadors and this has probably led to the misconception that the color red enrages bulls.

Professional experiments were conducted whereby matadors held different flags at different times. Some experiments included motionless red flags and in these cases the bulls were not enraged. Other experiments included waving flags that were not red, and the bulls became infuriated and aggressive. The resultof the experiments revealed that it was the motion of the waving cape/flag that elected extremely aggressive bulls. (Discovery).

A color psychologist, Jill Morton from “Color Matters”, explains that the term “colorblind” has one meaning but different dimensions. For example, dogs are colorblind creatures that see mostly shades of grey, blue, and yellow. (Color Matters). Bulls, however, have a different kind of colorblindness: they can only tell blue apart from other colors. As for the rest of the other colors, they all appear the same to bulls. (The Naked Scientist) 

Resources:

PETA, Bullfighting: A Tradition of Tragedy, Retrieved from,

http://www.peta.org/issues/animals-in-entertainment/bullfighting-a-tradition-of-tragedy.aspx

Discovery, Myth Busters Data Base, Retrieved from,

http://dsc.discovery.com/tv-shows/mythbusters/mythbusters-database/color-red-makes-bulls-go-ballistic.htm

Color Matters, How Animals See Color, Retrieved from,

http://www.colormatters.com/color-matters-for-kids/how-animals-see-color

The Naked Scientist, Science Questions, Can Bulls See Red, Retrieved from,

http://www.thenakedscientists.com/HTML/questions/question/1336/