In humans, especially teenage boys, one's body odor can cause most anyone to step away. Turns out gorilla B.O. can be "louder" or "softer" to communicate status, fear or more subtle information to those around them, researchers report after following a group for a year.
The odor became stronger from anger and distress, and when the mother of the youngest infant was not close by, the researchers said in the journal PLOS One. Not only can the odors signal emotional responses such as to danger, they can be modulated and can be used to regulate the behaviors of other gorillas, they said.
"Our results suggest that silverback odor strength can be 'turned up' or 'turned down' as well as 'turned on' or 'turned off' as a function of the context and relationship between the emitter and perceivers and that varying odor intensities may communicate different context specific types of information," said the researchers, Michelle Klailova and Phyllis Lee, from the University of Stirling in Britain. Klailova also is associated with other institutions.
The gorilla could use scent to get other gorillas to stay away, or to tell those in his group that he was there.
Mammals, the researchers noted, communicate with sounds and visual signals – and with chemical signals through smells for mate choice, resource defense and competition. The use of odor cues has been rarely studied, and the researchers wrote that this was the first study of wild gorilla "chemo-communication."
They observed the animals, 13 in all, for a year in the Central African Republic. That location might make odor especially important, the researchers wrote, because there is limited visibility in the forest.
Western lowland gorillas, or silverbacks, live in groups with one protector male. In this group, that was a silverback the researchers named Makumba.
The researchers set up an odor intensity index – ranging from zero for no detectable smell to 3 for extreme smells that became the only scent that could be detected by humans. Previous studies have shown that gorillas can discriminate among different odors, and they produce individually identified smells.
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