Tattoos have been used by humans for centuries in various cultures.
Researchers at the University of Wroclaw in Poland tested their hypothesis that tattoos were chosen to hide imperfections, a way to hide behind them. But what they found was that the men who got tattoos had a greater symmetry in their features, something considered to be more highly desired innately by women.
This leads to a new theory of men who tattoo themselves, that only those with a solid biological quality can risk the behavior of the needle which can cause infection. This shows a form of strength to endure injury and survive is a sign of Darwinian fitness.
This new perspective matches many traditional customs of tattoos in various cultures through the ages.