Spotted hyena in Kenya (photo credit: Joanna Goldby)
Spotted hyenas live in groups of 40-80 animals. These groups called ‘clans’ are complex and contain multiple subgroups that can be spatially distinct. Throughout the day different subgroups form and break up over and over again. Yet individual clan members are very successful at recognizing other members of their clan. This is important as hyenas are quite hostile to intruding hyenas from other groups.
How does a hyena know whether another hyena is an intruder? Besides visual and vocal cues, hyenas also do something called “pasting” which involves rubbing their anal scent glands against grass stalks and leaving a strong odor trail (humans can detect the smell more than a month after the pasting). A recent study published in Scientific Reports found that odor-producing bacteria from hyenas from the same group are more genetically related than bacteria from hyenas from different groups, and that “pasting” may be one method for how hyenas announce their clan identities (in fact, members of the same clan often paste on top of one another–presumably as a way to mix and share their “clan scent”). This research, performed by scientists at Michigan State University, is the first to provide evidence that hyenas harbor clan-specific bacteria in their scent glands.