A tattoo is a permanent marking made by inserting ink into the layers of skin to change the pigment for decorative or other reasons. Tattoos on humans are a type of decorative body modification, while tattoos on animals are most commonly used for identification or branding.
Tattooing has been a Eurasian practice at least since Neolithic times. Ötzi the Iceman, dating from the fourth to fifth millennium BCE, was found in the Ötz valley in the Alps and had approximately 57 carbon tattoos consisting of simple dots and lines on his lower spine, behind his left knee, and on his right ankle. Other mummies bearing tattoos and dating from the end of the second millennium BC have been discovered, such as the Mummy of Amunet from Ancient Egypt and the mummies at Pazyryk on the Ukok Plateau.
Pre-Christian Germanic, Celtic and other central and northern European tribes were often heavily tattooed, according to surviving accounts. The Picts were famously tattooed (or scarified) with elaborate dark blue woad (or possibly copper for the blue tone) designs. Julius Caesar described these tattoos in Book V of his Gallic Wars (54 BCE).Tattooing in Japan is thought to go back to the Paleolithic era, some ten thousand years ago.[citation needed] Various other cultures have had their own tattoo traditions, ranging from rubbing cuts and other wounds with ashes, to hand-pricking the skin to insert dyes.[citation needed
Tattooing in the Western world today has its origins in Polynesia, and in the discovery of tatau by eighteenth century explorers. The Polynesian practice became popular among European sailors, before spreading to Western societies generally