The chemical pigments that cause the coloration of auburn hair are often pheomelanin with high levels of eumelanin.
[citation needed] "Auburn" can be used to describe many shades of reddish hair with similar definitions or hues.
[6] Auburn hair is common among people of northern and western European descent,[7] but it is rare elsewhere.
Auburn hair occurs most frequently in Scandinavia (Denmark, Norway and Sweden), Britain, Ireland, continental Germanic Europe (Germany, Austria, the Netherlands, Belgium, and Luxembourg), northern France, Poland, and Russia.
This hair color is less common further south and southeast, but can occur somewhat regularly in Southern Europe (more so in Spain, and to some extent Portugal and Italy).