First Account of African Monkeys Eating Bats Raises Concerns About Spread of Zoonotic Diseases

For the first time, a recent study has captured African monkeys eating bats—a finding that raises concern about the spread of zoonotic diseases such as Ebola.

Elizabeth Tapanes, Florida Atlantic University in Boca Raton, and colleagues published the results of their study in the journal Ecohealth.

“[W]e provide the first behavioral details, accompanied by photographic and video documentation, of predation on bats by Cercopithecus monkeys, including C. mitis and a C. mitis x C. ascanius hybrid. These observations suggest an alternative pathway for bat-Cercopithecus disease transmission that has implications for zoonotic disease transmission to humans,” the authors write.

Although forest-dwelling Cercopithecus monkeys prefer to eat fruits and leaves, they are opportunistic omnivores and sometimes eat animals such as lizards, snakes, birds, and mice. These monkeys also share environmental and food resources with bats, which are known reservoir hosts for zoonotic organisms such as Ebola, Marburg and Henipa viruses, as well as some bacteria and parasites.

This has led researchers to hypothesize that monkeys’ consumption of fruits that are contaminated with an infected bat’s saliva or feces could allow zoonotic disease transmission. Yet, despite its potential to contribute to zoonotic disease transmission, the relationship between forest-dwelling bats and primates is poorly documented.

Tapanes and colleagues therefore conducted a study to examine Cercopithecus predation on bats after observing monkeys preying on two different bat species in Gombe National Park in Tanzania. The group is the first to have documented monkeys preying on bats, and they recorded this behavior using photography and video.

Over the course of approximately 6.5 years, the researchers observed 13 predation attempts on bats, and 11 successful kills, in 2 forests in Kenya and Tanzania. According to the authors, the monkeys’ behavior during the predation attempts showed that they consider bats to be a source of food: “Aggressive behavior and close visual attention to conspecifics, and an uncommonly long bout of alarm calls by a monkey that persisted in eating a bat rather than flee from an alarming stimulus indicate bats are desirable food items.” They also note that “[m]onkeys sometimes had prolonged contact with the bat carcass, consuming it entirely.”

Inevitably, the results of this study raise concerns about the potential for a different pathway for disease transmission between bats and monkeys. In addition to being exposed to diseases by eating fruits contaminated by bat saliva and feces, monkeys may also be exposed by handling and eating the bats.

The authors do, however, note that all predation events occurred near forest edges or human settlements. Indeed, monkeys in these regions have been forced to increasingly use these types of forest-edge and human-modified habitats in recent decades due to forest fragmentation and loss. They emphasize that “[w]hile effects of habitat change on bats are unknown and merit further study, our observations suggest that Cercopithecus preying on bats may be habitat specific, and possibly affected by anthropogenic habitat change”.

Nevertheless, Tapanes and colleagues conclude that ‘[p]redator—prey relations between bats and primates are little considered by disease ecologists, but may contribute to transmission of zoonotic disease, including Ebola virus.”

This article is co-published on www.americanveterinarian.com.

Dr. Parry graduated from the University of Liverpool, England in 1997 and is a board-certified veterinary pathologist. After 13 years working in academia, she founded Midwest Veterinary Pathology, LLC where she now works as a private consultant. She is passionate about veterinary education and serves on the Indiana Veterinary Medical Association’s Continuing Education Committee. She regularly writes continuing education articles for veterinary organizations and journals, and has also served on the American College of Veterinary Pathologists’ Examination Committee and Education Committee.