A tattoo is a marking made by inserting indelible ink into the dermis layer of the skin to change the pigment for decorative or other reasons. Tattooing has been practiced for centuries worldwide. Tattoos on humans are a type of decorative body modification while tattoos on animals are most commonly used for identification. Tattooing has been a Eurasian practice at least since around Neolithic times. Ötzi the Iceman, dating from the fourth to fifth millennium BC (found in the Ötz valley in the Alps), had 57 carbon tattoos consisting of simple dots and lines on his lower spine, behind his left knee, and on his right ankle. These tattoos were thought to be a form of healing because of their placement which resembles acupuncture. Other mummies bearing tattoos and dating from the end of the second millennium BC have been discovered (the Mummy of Amunet from Ancient Egypt). Today, people choose to be tattooed for cosmetic, sentimental/memorial, religious, and magical reasons, and to symbolize their belonging to or identification with particular groups (criminal gangs), but also a particular ethnic group or law-abiding subculture. Extensive decorative tattooing is common among members of traditional freak shows. While tattoos are considered permanent, it is sometimes possible to remove them with laser treatments (fully or partially). Pre-laser tattoo removal methods include dermabrasion, salabrasion (scrubbing the skin with salt), cryosurgery, and excision with skin grafts for larger tattoos. Tattoos have also been used for identification in other ways. Tattoos are sometimes used by forensic pathologists to help them identify burned, putrefied, or mutilated bodies.
