According to many penguins researchers, penguins grow their yellow hairs to make them attractive and mate.
Based on a spectroscopic analysis of macaroni penguins’ crest feathers and king penguins’ neck feathers, researchers found that the yellow features found on penguins are completely different from the yellow hair of all the other birds.
In birds, most yellow or similar color hairs come from food – birds eat something that contains yellow carotenoid pigments, like seeds, fruits, insects, etc. As a result, birds will have bright yellow feathers.
However, as discovered, nothing on penguins’ food list contains such a yellow carotenoid pigment that makes feather yellow. It’s believed that penguins will grow yellow hairs with internal pigment.
And the brighter the yellow hairs are, the most chance that a penguin will be loved by other penguins, and have more chances to mate.