As they drift in the air, they are carried backward in an inverted cone shape. An area dog crisscrosses from one edge of the cone and back to the other edge until the cone narrows and the lost individual is found. Trailing dogs follow a path of fallen skin cells that are similar to an article of clothing or a belonging of the missing person. Disaster dogs use a number of different techniques. In an earthquake, for example, Search and Rescue dogs are trained to indicate and locate human scent beneath rubble by barking as close to the location as possible.
Dogs can distinguish between living and dead humans and give off corresponding signals.
This is important when time is of the essence.