My colleague Pham Duc Tien and I spent most of a rainy afternoon in June 2008 working our way across slippery slopes to reach a mountainous stretch of Vietnam's Chu Mom Ray National Park as part of our bat-diversity survey. We happened upon the entrance to a small cave, but saw nothing to suggest it might be used by bats. The storm was worsening, however, so we decided to climb into the cave simply to escape the rain. That proved to be a fortunate choice.
We were surprised to spot several large bats within the cave, so we set up a harp trap at the entrance and quickly captured two rather large individuals – one juvenile and an adult. At first sight, their faces and other features looked like those of great leaf-nosed bats (Hipposideros armiger). However, we were surprised that they remained quite gentle while being captured and placed in separate cotton bags, actions that visibly anger great leaf-nosed bats. We also found that the echolocation calls of these bats were distinct from any leaf-nosed bat known in the region.
Thus began our years-long investigation of the bats from that nondescript little cave, which eventually proved to be members of a fascinating, new-to-science bat species that shines a spotlight on the diversity of Vietnam's bats.
Vietnam ranks among nations with the greatest biodiversity, and earlier surveys suggest that includes a rich variety of bat species. What has always been missing, however, were scientists trained to study bats. As the first Vietnamese biologist to specialize in bats, I had to look outside my country for professional guidance and research support.
Fortunately, I was able to find both. Grants from Bat Conservation International's Global Grassroots Conservation Fund, the Harrison Institute of the United Kingdom, the University of Tuebingen in Germany and others have supported my research into bat taxonomy and echolocation. A scholarship from the Government of Vietnam allowed me to earn my Ph.D. last year at the University of Tuebingen.
Much of my research has focused on the insectivorous horseshoe and Old World leaf-nosed bats of Vietnam. Both families are notable for the distinctive nose leaf – a complex and often-crinkled fleshy growth at the end of the muzzle. The nose leaves apparently are used to focus the bats' echolocation calls.
Many of these species are so similar in their morphology that they are often difficult to reliably identify. In fact, previous records that report some of these species in Vietnam appear problematic. In hopes of reducing the uncertainties and ambiguities, my teammates and I undertook a systematic study of the taxonomy and echolocation characteristics of these two bat families. From 2006 through 2011, following consistent protocols, we conducted bat surveys at various sites around the country, using hand nets, mist nets and harp traps to capture bats for measurements and identification. We also took tissue samples for genetic analysis and used bat detectors to record each bat's echolocation calls.
These surveys provided extensive data on bat diversity. And it was this project that brought us to the little cave in Chu Mom Ray National Park and the two captured bats. In addition to distinctive echolocation calls, lengthy examination revealed several key features of skulls and teeth that differed significantly from all known Hipposideros species. Genetic analysis also confirmed the uniqueness of these bats.
We twice revisited the cave and other areas of the national park to collect additional individuals, but were unable to find more bats with these characteristics. What we considered an exciting discovery remained uncertain for more than a year. In August 2009, as part of our surveys, we placed an echolocation-recording system beneath the forest canopy at the Cat Ba National Park, about 600 miles (1,000 kilometers) north of Chu Mom Ray. The recordings revealed echolocation calls similar to those of the two strange bats captured in 2008.
We set five mist nets across a footpath and collected three males and a female. Morphology, genetics and echolocation analysis all confirmed that these bats and those captured at Chu Mom Ray are identical. Meanwhile, we also captured several great leaf-nosed bats at Cat Ba, which were clearly differentiated from our new species.
Since the new species was first recognized by its echolocation frequencies, it is named after the late Professor Donald Redfield Griffin (of Cornell, Harvard and Rockefeller universities), who first reported bat echolocation in 1940 and who, in fact, coined the term.
This new species is Hipposideros griffini. It was officially reported in the February 2012 issue of the Journal of Mammalogy. Griffin's leaf-nosed bat received an unusual amount of attention from international news media, perhaps because of its somewhat peculiar appearance.
Our surveys, meanwhile, also revealed one species previously unreported in Vietnam (Hipposideros khaokhouayensis) and a subspecies (Hipposideros alongensis sungi) that is new to science. As more bat biologists begin working throughout Vietnam, they almost certainly will discover much more that is new and unusual. We have barely scratched the surface.
VU DINH THONG is a mammalogist/bat specialist at Hanoi's Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology.