The rats are trained to search for human odor. In the case of an earthquake, for example, the rats would be sent in. If they come across a human, a brain recognition pattern would be detectable, and the rescue team would know an area to search for survivors. Rats are obviously much more able than dogs or humans to get into small spaces and have an excellent sense of smell.

As creepy as I think rats are, I would be quite happy to see one of these guys if I was, say, trapped under three floors of rubble.