Bat Man of Borneo

“It’s like in Batman Begins, when young Batman is standing in a bat cave with the bats swirling all around him,” says National Geographic grantee Donald McFarlane, comparing his real-life work to a scene featuring the iconic superhero. McFarlane may not fly but, as a bat ecologist, he does repel hundreds of feet into the bowels of Borneo’s Gomantong Caves to study the bats that live there.

“We don’t worry about bats flying into us because it happens all the time. It’s going to happen continuously,” McFarlane explains, adding that the bats exist in “tremendous numbers.” And with tremendous numbers of bats come tremendous amounts of bat droppings and urine. McFarlane says he trudges through “pyramid-like accumulations of guano that are sometimes 60 or 70 feet high” and wears a face mask to protect his lungs from the dangerous levels of ammonia released from bat urine into the atmosphere.

Contact with bats and their excrement also puts McFarlane at risk for contracting rabies, histoplasmosis, and less studied tropical diseases. “It’s a pretty good environment to spread microorganisms,” McFarlane says.

So what exactly is McFarlane hoping to achieve by descending into this disease-ridden underground world? In part, he just wants to discover how far and how deep the caves go and push forward into the unexplored passages. But he’s also trying to figure out how bats and other cave dwellers are affecting the geology of the caves.

To fully comprehend the interaction between the caves’ geology and animals, McFarlane’s team is using state-of-the-art 3-D laser scanning technology and drone photography, and there’s no doubt that the sheer density of life is having a major effect on cave formation. “The cathedral-like passages that make the caves so spectacular in the first place do seem to be very largely created by the bats and birds,” says McFarlane. “It’s a case of the animals creating their own habitat in large part.” The bats and birds poop and pee so much that the excrement erodes the walls and actually makes the caves bigger, potentially by 50 percent.

The caves are also home to swiftlets, a type of bird whose nests have been harvested at Gomantong for about three centuries. McFarlane wants to better understand how the edible nest trade is effecting the swiftlet population in order to help advance sustainable practices. Swiftlet nests are considered a delicacy, as the saliva found in the nests is prized for its flavor and gelatinous texture.

Saliva, feces, and urine. It may not be sanitary, but it’s science!

See Pictures of Gomantong From Your Shot

More Video of Bats in Gomantong Cave



Nora Rappaport is a producer and editor on National Geographic's Science and Exploration Media team. She produces content that highlights the awe-inspiring work of National Geographic explorers around the globe. When not working with her colleagues to inspire people to care about the planet, Nora can be found hanging out with any number of dogs.