Hyenas Communicate with the Help of Bacteria

Hyenas, Africa's most successful predators, communicate with each other with the help of bacteria present in sour-smelling paste secreted by their clan members, according to a latest finding.

Other animals receive ample  information about the animal's sex, willingness to mate, social status and much more from these secretion,  reports LiveScience.

A team of researchers at the Michigan State University analyzed the bacteria present in the nasty-smelling scent posts and found that these contain symbiotic bacteria that play a key role in sending messages and have a mutually beneficial relationship with their hosts.

Hyenas that exhibit complex social behaviour, often scent mark their territories by pasting a secretion of rancid yellow substance on the grass stalks.  A large fist-size gland that is present beneath their tail near the anus secretes this substance. Hyenas adopt this strategy to optimise the distribution of scent marks over a massive area.

"When hyenas leave paste deposits on grass, the sour-smelling signals relay reams of information for other animals to read," Kevin Theis, the paper's lead author and MSU postdoctoral researcher, said in a statement. "Hyenas can leave a quick, detailed message and go. It's like a bulletin board of who's around and how they're doing. Scent posts are bulletin boards, pastes are business cards, and bacteria are the ink, shaped into letters and words that provide information about the paster to the boards' visitors. Without the ink, there is potentially just a board of blank uninformative cards."

All animals have microbial communities that make important vitamins and nutrients available to the host. Similarly, the microbial community in Hyenas is long suspected to play a key role in the animal's life.

To test this, Theis along with his colleagues collected pastes from striped and spotted hyenas from various locations in Kenya. On analyzing the paste samples in the lab they easily detected the presence of bacteria and also noticed a clear difference between the microbial communities of spotted and striped hyenas that reside in the same territory. The researchers identified 461 bacteria out of which only 11 bacterial groups were common between the striped and spotted hyena.

According to LA Times, the researchers identified that in one clan of spotted hyenas the microbial communities were different for males, pregnant hyenas and lactating females, as all the three had different subsets of microbe type that were unique to them. Out of 343 types, 120 were exclusive to males, 54 to lactating females and 46 to pregnant females.

With molecular survey the researchers looked at the diversity of the microbes inhabiting hyenas' scent glands. They also state that the diversity of the bacteria present in the scent gland that is responsible for the odor is in fact much greater than what the previous studies of mammals suggested.

"There have been around 15 prior studies pursuing this line of research," Theis said. "But they typically relied on culture-based methods, an approach in which many of the similarities and differences in bacterial communities can be lost. If we used those traditional methods, many of the key findings that are driving our research wouldn't be detected at all."

The team next plans to manipulate the bacterial communities present in the scent gland of the mammal to check if the change in their odor is predicted.  

The findings are documented in the current issue of the Proceedings of National Academy of Sciences.