For the first time, researchers have recorded African monkeys eating bats. And both are known to harbor diseases that can spread to people. These so-called zoonotic diseases include Ebola virus disease, and primates can become infected when they eat fruits contaminated by bat saliva or feces. But according to these new findings, published in EcoHealth this month, there’s an alternate – and more direct – route of disease transmission.
Cercopithecus monkeys are found in forests throughout Africa, and they prefer to eat fruit. But as opportunistic omnivores, they’ve also been known to eat leaves, bugs, and even lizards, snakes, birds, mice, and flying squirrels. These primates also share habitat and food resources with bats, but their predator-prey interactions have been poorly documented and thought to be rare – until now.
Accounts of Cercopithecus monkeys preying on bats in Tanzania’s Gombe National Park and Kenya’s Kakamega Forest date back to 1979. Using cameras and video recorders, Florida Atlantic University’s Elizabeth Tapanes and colleagues documented monkey predation on bats in Gombe and Kakamega between April of 2007 and October of 2014.
In that time, the team witnessed 13 bat predation events. The monkeys were successful 11 of those times. Individual monkeys spent between 10 and 66 minutes consuming a single bat (depending on size), and sometimes they’d eat the entire carcass, bones and all. Bats roosting in trees during the day were especially vulnerable to being snatched up since they were either torpid or asleep. And while feeding on bats, the monkeys would exhibit aggressive behavior, like growling.
In the two unsuccessful cases, several monkeys pursued just one bat. "The persistence of these monkeys to capture their prey indicate that bats are desirable items in their food repertoire," study co-author Kate Detwiler of Florida Atlantic University explained in a statement.
All of the hunting and feeding events happened in or near the edge of a forest or a human-modified habitat (like a plantation). It’s possible that deforestation and other sorts of man-made habitat changes have an effect on bat predation.
Observations of African monkeys handling and eating bats suggest that direct predation may be an important pathway of disease transmission. While cases of human infection mostly occurred through contact with infected primates, bats are also a reservoir for Ebola viruses.
Image in the text: Felix Angwella/Gombe Hybrid Monkey Project