Ear hair canal is sometimes trimmed for cosmetic reasons. Excessive hair growth within or on the ear is known medically as "auricular hypertrichosis". Some men, particularly in the male population of India, have coarse hair growth along the lower portion of the helix, a condition referred to as "having "hairy pinnae"" ("hypertrichosis lanuginosa acquisita"). Hair is a protein filament that grows from follicles in the dermis, or skin. With the exception of areas of glabrous skin, the human body is covered in follicles which produce thick terminal and fine vellus hair. It is an important biomaterial primarily composed of protein, notably keratin.
Human hair color can be found spread around most of Europe. Studies in 2012 showed that naturally blond hair of Melanesians is caused by a recessive mutation in tyrosinase-related protein 1 (TYRP1). In the Solomon Islands, 26% of the population carry the gene; however, it is absent outside of Oceania. Black hair is the darkest hair color. It has large amounts of eumelanin and is more dense than other hair colors. Auburn hair ranges along a spectrum of light to dark red-brown shades. The chemicals which cause auburn hair are eumelanin (brown) and pheomelanin (red), with a higher proportion of red-causing pheomelanin than