Naturally preserved or mummified bodies are rare, especially 5,000-year-old ones, so Ötzi the Iceman is quite an extraordinary find. Curious to discover why Ötzi is so well preserved, scientists have examined his body and conducted experiments to find the answer. All of Ötzi's toenails and body hair, and all but one of his fingernails had fallen off his body, as had the epidermis, or outer layer, of his skin. If his body had been preserved purely by being dried out, these items would have remained on his body. So his body had to have been preserved some other way.
Scientists know that bodies immersed in water for an extended period of time will lose their fingernails, toenails, and hair. Therefore, at some point, Ötzi must have been in water, not just ice, and this had to have happened before he was dried out and frozen. Another clue pointing to water submersion is the layer of fat under Ötzi's skin—it had turned to adipocere, also known as grave wax, which only forms when a body is in water. Adipocere is almost totally resistant to decay, and so the combination of the fat layer converting to adipocere and the body then drying and freezing, explains why Ötzi's body is so well preserved.