"It is widely believed that the human sense of smell is inferior to that of other mammals, especially rodents and dogs," John McGann writes in the abstract of his latest paper, recently published in Nature Neuroscience . However, McGann argues that it might not be how strong our sense of smell is, but what we're trying to smell.
"Dogs may be better than humans at discriminating the urines on a fire hydrant and humans may be better than dogs at discriminating the odors of fine wine," he writes.
It was originally thought that sense of smell was based on the size of the olfactory receptors, according to IFLScience.com. French physician Paul Broca, in particular, suggested in 1879 that the smaller the olfactory receptor relative to the brain served as the main indicator of how strong or weak a species sense of smell would be. McGann argues that this isn't the case and that "there is no evidence that sense of smell is directly linked to the size of the olfactory bulb, and our sense of smell is just as good as that of other animals," Johnathan O'Callaghan wrote.
McGann ultimately concluded that the number of neurons, which are comprable in both humans and other animals, that determines strength of sense of smell.