Getting Into Some Bat Business
Updated: Jul 25, 2020
On a recent work trip to Myanmar I decided to put the elephants to one side briefly and get mixed up in some bat business. Smithsonian researchers have been working in Myanmar for around 30 years with different research projects across many fields. One of the research teams with whom we have a lot of overlap is the Smithsonian Global Health Program who do incredible work all over the world including being part of the “PREDICT” program which uses the expertise of medical doctors, veterinarians and ecologists to identify potential pandemic diseases arising from human/animal contact and build capacity in developing countries to monitor them. This means that the team spend a lot of time taking samples from animals that humans interact with either directly or indirectly to identify what pathogens are out there and how they might be spread.
My good friend and colleague Dr. Marc Valitutto collaborates with us on our elephant work and helps to train local veterinarians in disease monitoring and management. Marc recently approached me to ask if I would advise him and his intern Jennifer Kishbaugh on a bat tracking project. These large fruit bats (Pteropus giganteus.) roost in trees in the middle of villages, close to schools and in one case directly above a small pig farming operation. They could potentially be shedding pathogens all the time and Marc and his team had a good idea of what they might be carrying but the missing piece was where are they coming from and going to. Attaching tracking devices to these bats could answer a multitude of important questions. How far do they travel in a day, a week, a month? How many different locations do they visit? What kind of mixing occurs between groups of bats? What are the environmental conditions in the places they visit? All of these questions could really shine a light on not only the ecology of these bats but also on the potential flow of disease across a human impacted landscape.
After a few months of development and trial and error with setting up technology and a lot of hard work from Jen who had never been involved with this kind of work, the project was ready to go. We went with a collaring system that uses a direct download of data to a base station. The bats go about their batty business with the collar logging their position every hour and when they return within range of the base station the data is downloaded and we find out where they have been. This does have the drawback of not transmitting remotely and if the bats decide to move their roost or some other fate befalls them we don’t get any information. There is a lot to be said about the various trade-offs of collar weight, battery power, sampling rates and ease of data collection but I think that is best saved for another post. The system used here was the best choice given all the various criteria we needed to meet.
The bats were captured around their roost tree using mist nets. The netting and extraction was handled expertly by our local partners who have been catching bats for many years (although rarely for research!). On our first trip we had a bit of false start where technological issues combined with field logistical problems meant we spent a few long nights and only captured some smaller (but still cool) bats like the Greater short-nosed fruit bat (Cynopterus sphinx). After regrouping and rethinking a bit the team went out for round two and I planned to join them the following day as i was in Bangkok doing elephant related things.The team were actually so successful at catching bats that they deployed all 10 collars on male bats the day before I arrived on site. I still got to assist with the capture and sampling of a few bats but didn’t get to actually see the collars go on and will have to content myself with looking at the data as it comes in. The bats had measurements, swabs and blood samples taken and were given some sugar water to keep them happy during the short handling period.
So far we have seen some fairly typical bat behaviour with different bats heading off to different feeding sites mostly within a 10km range of the communal roost. Bats will revisits the same feeding site for a few nights in a row if it is profitable. Sometimes we see that other bats catch on to the fact that their neighbour has found a good spot (perhaps by smelling them) and follow them to that area the next night. There are a lot of gaps in the data possibly down to the dense canopy of the roost trees making transmission difficult and from bats taking longer journeys. After a worrying couple of weeks one bat returned to the roost site and showed that he had been 73km away for a few days.
The next steps for this project will be to complete disease surveys of animals and humans at the roost site and at the feeding sites identified through the tracking data and to hopefully deploy a lot more collars at more locations and really build up a map of where these bats move around the country as they represent an important vector for potential disease outbreaks.
My involvement with the bat project was supported by the Smithsonian Movement of Life Initiative.