Please pay attention as there will be a test when you are done.
The tricky thing about colour blindness is that many people don’t know they are colour blind until they get tested (40% of colour blind pupils currently leaving secondary school are unaware that they are colour blind – http://www.colour-blindness.com/general/prevalence/). Why would they? They naturally assume that what they have seen all their lives is correct just like the rest of us. My optometrist told me once that he was doing an eye exam for a person wanting to become a police officer who was severely dismayed to hear that he was colour blind and therefore, could not pursue his dreams.
Red Green Colour Blindness is caused by a gene on the X chromosome therefore, since males have 1 X and 1 Y while females carry 2 X’s, this issue is predominately found in males (7-10% of the overall population) and is very rarely seen in females. For these people, they cannot see red and green light.
Blue Colour Blindness is equally unlikely for both males and females as the deficient gene is found on chromosome 7 which is not sex-linked. The issue is caused by a mutation in the gene which prevents the person from seeing blue light.
In both these cases, the problem isn’t as straight forward as not seeing blue, red or green light. If what they are looking at contains these colors, they will not be seen.
Want another explanation? Here’s an excellent video
So now that you know a little more, how many animals can you see? CLICK HERE to see the answer.