A British experiment found that after separating female dog from their young children, they were mixed with a group of adult dogs and puppies of the same kind, and then put the female dogs into the pack. The female dog will soon join her children. Studies have shown that dogs' body odor is the basis on which they identify each other. Puppies can't tell the smell of their mother from that of other female dogs. So every female dog can tell the smell of her children.
The method used in the above argument is to determine one of the two alternative interpretations of a phenomenon by excluding the other.