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Ghost Bats and Gold Mines
Underground across the north of Australia, a unique native mammal finds shelter where humans have found precious metals.
Get to know the ghost bat
Its eldritch name might conjure scenes from Halloween and spooky movies, but the ghost bat proves it’s more than that with unique anatomy and impressive acoustic abilities.
Officially known as Macroderma gigas, the ghost bat is the only living member of its genus, meaning technically that no other bat’s scientific name starts the same way and genetically that no other bat is quite like it.
On a global scale, about 20 per cent of all mammal species are bats. That means there are a lot of different bats! Of those, the ghost bat is one of the few carnivores. The species is listed as vulnerable under federal legislation in Australia.
Ghost bats are ferocious predators that feed on frogs, birds, reptiles, small ground-dwelling mammals and sometimes even other bats. What’s more, they find their prey in the dark of night, through a combination of specialised senses.
On their evening expeditions, ghost bats make use of vision, hearing and echolocation to hunt. This is aided by their large eyes, long ears and a specialised structure known as a nose-leaf — fancy nostrils, if you will. Together with the pale fur that earns the ghost bat its name, these features make for a creature ‘globally unique’ in appearance.
A ghost bat’s face up close. Photo credit: Dr Nicola Hanrahan
The ghost bat’s nose-leaf is particularly striking, in both form and function. When the bat emits sound produced by the larynx, the nose-leaf helps to focus the outgoing pulses into a directional beam. The bat will then listen out for returning echoes to identify where they are and what's around them. Humans can learn to do this too, as remarkable individuals like Daniel Kish demonstrate.
When daylight comes, ghost bats typically return to a long-term roost site. Female ghost bats in particular are philopatric, meaning they return to the roost site where they were born. The roosts are often underground, deep in caves or disused mine sites. It’s the latter, of course, that make the connection between ghost bats and gold mines.
A gold mine in the historic town of Pine Creek south of Darwin, for example, has been known to host ghost bats for many decades. Shared interest in such sites, between the bats, conservationists and prospectors old and new, makes it all the more important to understand the nuances of ghost bat life.
However, among the ghost bat’s remarkable traits are those that make it particularly challenging to study: they’re active at night, live underground and often use sounds that we can’t hear. Luckily for the ghost bat, researchers are up (at all hours) for the challenge.
Ireland to the arid zone
Dr Nicola Hanrahan was studying undergraduate science in Dublin, Ireland, when she was first introduced to bats. A particularly passionate lecturer of hers often used bats as examples in teaching, and this made a strong impression on the budding bat ecologist. That same lecturer went on to supervise Nicola’s honours research, a lab-based study of bat genetics.
Dr Nicola Hanrahan. Photo credit: Hannah Maddison-Harris
Nicola went on to meet the ghost bat while working as an ecological consultant across the Top End and Central Australia. Her own words best express how she was drawn by the unique characteristics of the species: ‘Wow, they are crazy!’
Drawn also by the chance to do something different, Nicola went looking for research opportunities. At the BatsLab at Western Sydney University, she found just that with a PhD scholarship for a project focusing on the social vocalisations of the ghost bat. This research laid the foundation for studies continuing to this day.
Now based at Charles Darwin University, Nicola is a postdoctoral researcher in the Macroderma Lab. As for the reputation of a career in bat research now, Nicola reports two very different reactions. ‘Eww, I don’t like them’ offers an opportunity to dispel myths, while ‘Oh I love them!’ means she’s found a fellow bat aficionado.
Studying the sounds of a spectre
Ghost bat calls are many and varied and aren’t always out of human hearing range. Through a series of increasingly in-depth studies, Nicola and her colleagues have documented a whole range of ghost bat calls.
Over a two-year study, 12 distinct non-echolocation vocalisations were identified, from chirps and trills to whistles and squabble calls. Moreover, there were clear differences between colonies, akin to different human dialects.
Previously, researchers studying bat calls would use the technique of ‘downshifting’ or ‘downscaling’ recordings of bat calls to a level audible by the human ear. Some researchers can even identify bats by those adjusted tones alone! These days, researchers can also use graphical representations known as spectrograms.
Comings, goings and conservation
Another aspect of getting to know the ghost bat is studying their activity patterns. For this, a day in the field might begin around 4 pm with setting up a net in the vicinity of a roost to catch the bats as they emerge. From shortly after sunset through to midnight, the researchers will be kept busy tagging and examining the bats before sending them on their way.
A ghost bat being released. Photo credit: Dr Nicola Hanrahan
As Nicola puts it, captured ghost bats are not 'super feisty’ but will, naturally, look for a way to get away. They do have big teeth but also ‘a super sweet face’. In fact, they tend to stay quiet in researchers' hands and might even close their eyes and stick their tongue out. Given the opportunity, they are still capable of biting, so researchers take precautions, wearing thick gloves, doing training in handling and keeping up to date with vaccines that protect against Australian bat lyssavirus.
Captured bats will often be given a PIT tag, much like the microchip your dog or cat might have. In the Top End, over 100 bats in the Pine Creek colony have now been tagged, and an antenna has been installed at the mine entrance. At around 3:15 each afternoon, Nicola gets an email with an update on bat movements past the antenna.
Knowing a few demographic facts about each bat along with when they come and go gives researchers more clues about cave life from the outside. Females, for example, might leave the roost later or return earlier to spend more time with pups.
Nicola will soon be heading out into the field to see the Pine Creek bats in person again and collect data for comparison and consolidation with findings from the same time last year.
With each new piece of information gleaned from fieldwork, lab work and collaboration, researchers are building up a knowledge base on bats to better protect them. A national ghost bat recovery plan has just been released, and Nicola hopes the shared interest of industry will provide an incentive for continued work to inform conservation.
More broadly, there’s hope that ongoing research will support monitoring techniques that suit other species that are under threat and hard to study. As for ghost bats in gold mines and beyond, each new finding will inform steps for protection, squabble call by squabble call and sweet face by sweet face.
A ghost bat roosting. Photo credit: Dr Nicola Hanrahan
References
Bat Call WA. (2021). A review of ghost bat ecology, threats and survey requirements. https://www.dcceew.gov.au/sites/default/files/documents/review-ghostbat-ecology-threats.pdf
Garrick, M. (2020, January 29). Threatened ghost bats a “main issue” for Northern Territory gold mine’s green light. ABC News. https://www.abc.net.au/news/2020-01-30/ghost-bat-population-in-pine-creek-under-threat/11909568
Griffiths, S. R. (2013). Echolocating bats emit terminal phase buzz calls while drinking on the wing. Behavioural Processes, 98, 58–60. https://doi.org/10.1016/j.beproc.2013.05.007
Hanrahan, N., Armstrong, K. N., Turbill, C., Dalziell, A. H., & Welbergen, J. A. (2026). Dialect formation in ghost bats: Genetic, geographic and morphological drivers of social and echolocation call divergence. Ecology and Evolution, 16(1). https://doi.org/10.1002/ece3.72797
Jameson, J. W. (2024). Buzzfindr: Automating the detection of feeding buzzes in bat echolocation recordings. PLOS ONE, 19(8), e0306063. https://doi.org/10.1371/journal.pone.0306063
Ottewell, K., Prada, D., Umbrello, L., & Sun, R. (2024). Interview with a (false) vampire. In Department of Biodiversity, Conservation and Attractions. https://www.dbca.wa.gov.au/landscope/winter-2024/interview-with-false-vampire
Ruykys, L., Hanrahan, N., Leiper, I., & Gonsalves, L. (2026). Home Range and Movement of the Ghost Bat (Macroderma gigas) in the Katherine Region, Northern Territory. Austral Ecology, 51(3), e70193. https://doi.org/10.1111/aec.70193
Ruykys, L., Hanrahan, N., & Stokeld, D. (2024). Northern Territory guidelines for surveying for the ghost bat at the landscape scale. Charles Darwin University Press.
Silver, L. W., Hanrahan, N., Banks, S. C., Armstrong, K. N., Hogg, C. J., & Ottewell, K. M. (2025). The complete genome sequence of the ghost bat, Macroderma gigas. F1000Research, 14, 1445. https://doi.org/10.12688/f1000research.172914.1
Smyth, B., & Nebel, S. (2013). Passive integrated transponder (PIT) tags in the study of animal movement. Nature Education Knowledge, 4(3). https://www.nature.com/scitable/knowledge/library/passive-integrated-transponder-pit-tags-in-the-101289287/