Wednesday, May 25, 2016

Cercopithecus monkeys opportunistically prey on bats

C. mitis, photo Diana Robinson
Two species of Cercopithecus monkeys in Kenya have been observed and documented feeding on bats when the opportunity presents itself. Tapanes and colleagues (2016) photographed and filmed this behavior in Blue monkeys, Cercopithecus mitis, and in one monkey which was a hybrid species of C. mitis and C. ascanius, the Red-tailed monkeyThey report on thirteen observations of bat predation attempts over six and a half years at two sites, Gombe in Tanzania and the Kakamega Forest in Kenya). Of these thirteen attempts, eleven were successful. Surveying researchers of blue and red-tailed monkeys at other sites did not identify further instances of bat predation.

Although identifying the bats was challenging, Tapanes and colleagues determined that multiple species of bats were consumed. Researchers observed two instances where an individual grabbed a lone roosting bat and consumed it. In the other observations, the researchers did not witness the individual capturing the bat.

Unsurprisingly, the evidence suggests that bats are a preferred food item for Cercopithecus monkeys. In two of a successful predation event, other monkeys gathered around and observed the monkey feeding on the bat. Three instances were observed where some sort of aggressive display or behavior to either obtain or retain the bat, implying this food item is worth fighting over.

All observed instances of this behavior occurred in either forest edges or human-modified habitat, raising the question as to whether or not this behavior occurs naturally or is a product of habitat destruction and alteration due to human activities. It is possible that anthropogenic changes to the landscape have resulted in blue and red-tailed monkeys altering their feeding patterns and behaviors accordingly, with increased consumption of bats as a potential modification. Thirty-six years of data collection at Kakamega forest show that bat predation coincides with increased use of plantation forests that has occurred due to forest fragmentation and loss. Tapanes and colleagues (2016) also suggest that bat predation could be more widespread, but it is simply easier for researchers to observe this rare behavior within altered habitats. They do not think this reason is likely, stating that observation conditions were similar in both plantation forest and forest that is more natural.

Blue monkey feeding, photo Christoph Strässler
These findings have important implications for the transmission of zoonotic diseases, or diseases that can be transmitted from animals to humans. It has previously been hypothesized that primates contract diseases from bats when they consume fruit with an infected bat's saliva or feces (Dobson, 2005; Alexander et al., 2015; Rodhain, 2015). This latest study forces us to consider the fact that directly handling the bats themselves may be a method for disease transfer. As monkeys can transmit many diseases to humans, it is worth studying this phenomenon more, if possible.

Links of potential interest:
IUCN Redlist page for C. mitis
Primate zoonotic diseases
Which primate is likely the source of the next pandemic?
Ebola, primates, and bushmeat

Works cited:
Alexander, K. A., Sanderson, C. E., Marathe, M., Lewis, B. L., Rivers, C. M., Shaman, J., ... & Eubank, S. (2015). What factors might have led to the emergence of Ebola in West Africa?. PLoS Negl Trop Dis, 9(6), e0003652.
Dobson, A. P. (2005). What links bats to emerging infectious diseases?. Science, 310(5748), 628-629.
Rodhain, F. (2015). Chauves-souris et virus: des relations complexes. Bulletin de la Société de pathologie exotique, 108(4), 272-289.
Tapanes, E., Detwiler, K. M., & Cords, M. (2016). Bat Predation by Cercopithecus Monkeys: Implications for Zoonotic Disease Transmission. EcoHealth, 1-5.