Sniffing, a common behavior in dogs, cats and other animals, has been observed to also serve as a method for rats to communicate-a fundamental discovery that may help scientists identify brain regions critical for interpreting communications cues and what brain malfunctions may cause some complex social disorders.
Researchers have long observed how animals vigorously sniff when they interact, a habit usually passed off as simply smelling each other. But Daniel W. Wesson, PhD, of Case Western Reserve University School of Medicine, whose research is published in Current Biology, found that rats sniff each other to signal a social hierarchy and prevent aggressive behavior.
Wesson, who drew upon previous work showing that, similar to humans, rodents naturally form complex social hierarchies, used wireless methods to record and observe rats as they interacted. He found that, when two rats approach each other, one communicates dominance by sniffing more frequently, while the subordinate signals its role by sniffing less. Wesson found that if the subordinate didn't do so, the dominant rat was more likely to become aggressive to the other.
Wesson theorized the dominant rat was displaying a "conflict avoidance signal," similar to a large monkey walking into a room and banging its chest. In response, the subordinate animal might cower and look away, or in the case of the rats, decrease its sniffing.