For camoflauge. A leopard, tiger and lion all have the same type of coloring ..kind of. The yellow hides the giraffes' legs in the long savana grasses.God has created a self protective mechanism for every creature
I think it's a variation of the basic wild animals hair colour which is agouti - each hair contains bands of black, brown and yellow or black brown and white, so early colour mutations to crop up tend to be black, yellow or brown and if one proves to be advantageous in terms of less easily spotted by predators that animal will breed more and produce offspring like it.
Giraffe's aren't exactly yellow. They are spotted in an intricate pattern that can include yellow, orange, and red spots, and can also look a tan like brown. The number of spots is unique to each giraffe. It does help them to blend in with the branches in the trees.
Over the course of hundreds and hundreds of years, giraffes that are yellow with brown spots have been more likely no survive, reproduce and produce offspring than giraffes of other colors. Hence, we now have yellow giraffes. Giraffes with this color scheme are more camouflage and less likely to fall victim to a predator. It is an example of evolution and natural selection.
I have a normal corn and one that has no brown at all, just black gray and yellow bottom what will iokay, I have a normal and one that is black with no brown but some yellow on the bottom not sure what that is called...