People have also been forcibly tattooed. A well known example is the identification system for inmates in Nazi concentration camps during the Holocaust. Tattoos have also been used for identification in other ways. For example, in the period of early contact between the Māori and Europeans, Māori chiefs sometimes drew their moko (facial tattoo) on documents in place of a signature. Tattoos are sometimes used by forensic pathologists to help them identify burned, putrefied, or mutilated bodies. Tattoo pigment is buried deep enough in the skin that even severe burns are not likely to destroy a tattoo.[citation needed] For many centuries seafarers have undergone tattooing for the purpose of enabling identification after drowning. In this way recovered bodies of such drowned persons could be connected with their family members or friends before burial. Therefore tattooists often worked in ports where potential customers were numerous. The traditional custom continues today in the Royal Navy (Great Britain) and in many others.

Tattoos are also placed on animals, though very rarely for decorative reasons. Pets, show animals, thoroughbred horses and livestock are sometimes tattooed with identification and other marks. Pet dogs and cats are often tattooed with a serial number (usually in the ear, or on the inner thigh) via which their owners can be identified. Also, animals are occasionally tattooed to prevent sunburn (on the nose, for example). Such tattoos are often performed by a veterinarian and in most cases the animals are anesthetized during the process. Branding is used for similar reasons and is often performed without anesthesia, but is different from tattooing as no ink or dye is inserted during the process.