Let us set the scene.

We have all come across this image at some point. The brave and foolish matador vexes the bull by swaying a vibrant red cape. The bull, utterly incensed, rampages straight toward it, hurtling with dangerous aggression. He is evaded with a flourish, and the dance continues…

Without his bright red cape, the matador would surely be incapable of exciting the rage of his bovine opponent. Except, there’s a problem with this theory.

Cows can’t see the colour red.

In truth, cows are dichromatic organisms. This means that their eyes only perceive variations of two colours - yellow and blue. They have no red-receptors on their retinas, making them colourblind to even the swankiest of capes.

On the other hand, we are trichromatic - meaning we see blue, yellow, and crucially red as well.

Of course, humans can be born with dichromatic conditions, limiting our colour vision - in some cases quite severely.

Protanopia and deuteranopia are both forms of red-green colourblindness, meaning that wavelengths in the red-to-green spectrum will be confused. Colours like orange, brown and other similar shades can become difficult or even impossible to differentiate.

There is also the very rare tritanopia, which affects only one out of every 100,000 people! This unusual condition affects our ability to see the colour blue, and totally changes the way you see the world.

While some of us have more in common with bulls than others, don’t believe anyone who tells you that it is the colour red that makes them angry.

They simply dislike capes and the merry gentlemen flaunting them.

Sources:

1. ColourBlindAwareness.org.
2. BlueCross.org.
3. ‘The perception of color by cattle and its influence on behavior’ - CJ Phillips, CA Lomas.
4. ‘Are Cattle Colourblind?’ - Pets.on.mom.com .