A search-and-rescue (SAR) dog is a dog trained to respond to crime scenes, accidents, missing persons events, as well as natural or man-made disasters. These dogs detect human scent, which is a distinct odor of skin flakes and water and oil secretions unique to each person and have been known to find people under water, snow, and collapsed buildings, as well as remains buried underground. SAR dogs are a non-invasive aid in the location of humans, alive or deceased.