Researcher Daniel Thomas told the Smithsonian Insider : “Penguins use the yellow pigment to attract mates and we strongly suspect that the yellow molecule is synthesised internally.

“[It’s] distinct from any of the five known classes of avian plumage pigmentation and represents a new sixth class of feather pigment.

“As far as we are aware, the molecule is unlike any of the yellow pigments found in a penguin’s diet.”