In a study conducted by Udo Groeger and Lutz Wiegrebe from the Ludwig-Maximilians-Universitaet in Munich, Germany, two vampire bats were taught to associate recordings of different humans breathing with different cattle blood dispensers, providing food rewards. They were then played short clips of people breathing and had to associate them with the correct individual by going to the correct dispenser. Four human participants were asked to associate the same short clips with the correct individual.
The vampire bats were able to spontaneously associate the clips with the particular individuals, regardless of whether the individual was recorded breathing at rest or breathing while under physical strain. The human participants were also able to recognise some clips, but they were unable to recognise the clips of breathing recorded under physical strain.