Cadaver dogs are trained to specifically find the odor of decomposing *human* remains.
Cadaver dogs are trained to ignore live human scent and animal scent, and only indicate on human remains. These dogs can be used to find human remains related to crime scenes, missing persons cases and forensic evidence related to decomposing human remains.
Cadaster
Cadaver dogs that have special training in the context of disaster scenes and debris (cadaster dogs) can also be used to locate human remains following a natural or manmade disaster. Illinois Search Dogs routinely cross-trains their cadaver dogs to be operational as cadaster dogs as well, to compliment our disaster dog teams.
Water
A specialty subset of cadaver dogs is water cadaver dogs. Similar to cadaver dogs, these dogs have been trained to find the odor of decomposing human remains. However, water cadaver dogs have been specifically trained to locate and indicate the source of the odor to assist divers in a more directed and speedy recovery of a drowning victim.
http://www.illinoissearchdogs.org/capabilities/cadaver_dogs.shtml