Scent-Gland Bacteria Help Hyenas Identify Friends, Strangers, and Pregnant Females

By Joseph Castro | July 8, 2011 12:53 pm

spacing is important

Spotted hyenas are sometimes portrayed as cowardly scavengers, always laughing, always up to some kind of mischief. If you’ve ever seen Disney’s The Lion King, then you may already have that image in your head. Here in the non-Disney universe, spotted hyenas are actually fascinating creatures. For example, they hang out in matriarchal “clans,” and the females, with their aggressive behavior and pseudo-penises (large clitorises), are very difficult to tell apart from the males. But it turns out that spotted hyenas may be even stranger than we initially thought: they may use bacteria to help communicate with one another, suggests Michigan State University zoologist Kay E. Holekamp in a recent, amusing New York Times blog post.

Unlike many other carnivorous species, spotted hyenas do not mark their territory by lifting their legs and peeing. Instead, the animals produce a yellowish paste in their scent glands located above their anuses. The paste accumulates in adjacent pouches, which the hyenas then rub on grass stalks. In previous research, Holekamp and her students learned that the paste odor provides a wealth of information to roaming hyenas, such as the sex of the paste owner, whether it’s pregnant or lactating, and which clan it’s from. But how does this all work?

Kevin Theis, one of Holekamp’s former PhD students, realized that the anal pouches are warm, wet, and rich in nutrients, making the sacs the perfect breeding ground for growing bacterial colonies. When he analyzed the communities of bacteria in hyena pouches, he learned that the microbes vary among different social groups, and they help produce various odors in clans, families, individuals, and females in different reproductive stages.

Holekamp suspects that young hyenas actually pick up the bacteria from other hyenas’ pastes, since the cubs rub their sacs on grass stalks even though they don’t generate paste themselves. She also thinks that male spotted hyenas adopt microbial colonies in the same manner when they join other clans.

To find out, Holekamp and her students are collecting more anal paste to analyze. After a hyena deposits its paste on the stalks, her students walk slowly through the grass, sniffing individual stalks to find the deposits. The students look like “demented entomologists searching for new life forms,” Holekamp wrote in her blog.

Add that to your list of jobs you probably don’t want.

(via New York Times)

Image: Flickr/Tambako the Jaguar


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