People smell as well as dogs do

" ...a study at the University of California Berkeley reports that if humans keep their noses to the ground they can indeed follow a scent much like a dog (though not as effectively as a bloodhound, the sad-faced dog that can detect a scent four days old with a nose said to be a million times more sensitive than a human's)... " Reported on CBC News Dec. 18, 2006.
My first reaction was "No way!" But then again, stick your nose into the lawn...and, Who'd a thunk?