How do fruit-eating bats handle so much sugar without getting sick? Understanding this could help us better understand healthy sugar metabolism and metabolic disease in mammals including humans. Fruit and nectar is high in sugar, yet bats can consume large amounts without developing the metabolic problems that high-sugar diets can cause in humans and other mammals.
Researchers from the Welch Lab at the University of Toronto visited us to study this in tube nosed fruit bats, spectacled and black flying foxes. Our results showed patterns of sugar metabolism comparable to those seen in wild Gray-headed Flying Foxes caught near Sydney. This indicates that our bats have no signs of insulin-resistance or other metabolic impairments, which can be associated with captivity in mammals. Additionally, out bats showed similar patterns of sugar metabolism to other species of fruit-feeding bat that live hundreds of miles away in Asia, Africa, and the Americas. Notably, bats in the Americas evolved fruit-feeding independently from those in Asia, Africa, and Australia. Therefore, all species of fruit-feeding bat across the globe having similar patterns of sugar metabolism despite having multiple independent origins of frugivory reveals that these animals have likely converged upon a common optimal metabolic solution for healthily processing the sugar found in a fruit-based diet for mammals.
Mapping Bat Wing Vasculature to Better Understand Flight and Thermoregulation
Lilly Pinkston visited Tolga Bat Hospital in July 2026 to photograph the intricate blood vessels inside the wings of our bats as part of an exciting international research collaboration.
Lilly is a senior undergraduate from the Rummel Lab at Rice University in the United States, where researchers study how bats fly, move, and regulate their body temperature. The research is interested in locomotor physiology, biomechanics, and urbanisation of bat species. They are particularly interested in the influence of environment, morphology, and flight behaviour on the regional heterothermy exhibited in bat wings during flight. Regional heterothermy is achieved via blood flow dynamics, suggesting it is key to understanding bats’ unique thermoregulatory abilities.
Regional Heterothermy: Different parts of the body maintain different temperatures simultaneously. For example, a bat might keep its core warm while allowing its wings to drop close to the air or water temperature.
Understanding how Murray’s law applies to bats provides insight into how this diverse order regulates their temperature in the face of a variety of energetic challenges. “Murray’s Law states that the cube of the radius of a parent blood vessel equals the sum of the cubes of the radii of its branching daughter vessels. This principle optimizes fluid transport by minimizing both the energy needed to pump fluid and the metabolic energy required to maintain the blood volume. (Wikipedia)”
To assess their adherence to Murray’s Law as an order, mapping the circulatory system of a diverse range of bat species is necessary. During Lilly’s visit, she photographed the wing vasculature of 7 different Australian bat species. These detailed images will be analysed and compared to bat species from across the globe for structural differences that may influence thermoregulatory mechanisms and flight.
Greater Broad Nosed Bat
Freetail Bat
Shealthtail Bat
Comparing thermoregulatory responses in four flying-fox species under shared environmental conditions
Samantha Yabsley
PhD candidate, Hawkesbury Institute for the Environment, Western Sydney University
Supervisors: Professor Justin Welbergen, Dr Jessica Meade, Associate Professor Christopher Turbill.
Samantha has put cameras, temperature loggers and a weather station at our large flight cage in order to observe the thermoregulatory behaviours of 4 species of Australian flying foxes throughout the year.
Her work at Tolga Bat Hospital contributes to the Animal Ecology Lab’s long‑running research program aimed at understanding how extreme heat affects flying‑foxes, and why outcomes differ among species and conditions (https://www.animalecologylab.org/flying-fox-heat-stress.html). Within this broader program, the current project involves observing flying-fox thermoregulatory behaviours and recording the weather conditions under which they are expressed. Tracking the timing and progression of these behaviours across a range of weather conditions provides a useful framework for assessing how individuals are affected by different types of heat (e.g., dry heat versus humid heat) thereby informing how management responses can help lessen the impacts of these events on the species.
In the wild, very few flying-fox camps are known to comprise all four mainland species, and their simultaneous occurrence is rare (Finch Hatton Gorge, and previously Ingham). Tolga Bat Hospital’s permanent care aviary provides a unique opportunity to compare thermoregulatory responses across all four species under shared environmental conditions.
Read about this research here
The researcher Sam Yabsley helping at a heat stress event
Multiple Spectacled flying fox Investigations
Dr Lee McMichael, Veterinary School, University of Queensland.
Every year we need to euthanase hundreds of Spectacled flying foxes with tick paralysis that is too advanced for them to be treated successfully, but are in otherwise excellent condition. Dr Lee McMichael from the University of Queensland Veterinary School has a number of projects with us to learn as much as possible from these bats and others. Her research focuses on tick paralysis, cleft palate syndrome and retroviruses. In the 2021 tick season we kept the blood, tick and body of each of these euthanased bats. We included the bats treated for tick paralysis as well, keeping the tick and blood once the bat had fully recovered. This will allow a study of tick genetics, tick borne pathogens, tick toxin tolerance and efficacy of treatments. Four Spectacled pups with cleft palate syndrome were collected, and during the year one adult female in the early stages of gestation whose injuries necessitated euthanasia. Genetic analysis of animals with congenital birth deformities and the expression of genes during foetal development will help us understand the complex interaction between genetics and environmental factors that cause such deformities. Examination of animal samples at a population level will help us investigate the effect of environmental toxins and assess the impact of retroviruses that may lead to co-infection with other pathogens that can seriously impact the health of the endangered spectacled flying foxes.
Climate change and the impacts of extreme events on Australia’s Wet Tropics Biodiversity
Dr Justin Welbergen
One of the greatest unknowns in global climate change science is how changes in extreme events will impact on the natural world. Emerging evidence strongly suggests that changes in the frequency, duration and intensity of extreme events (e.g., heat waves) will be even more important than gradual increases in climatic means in driving ecological responses to climatic change. Our research program examines what drives vulnerability of terrestrial biodiversity to temperature extremes in order to make robust predictions of impacts under future climate scenarios.
It focuses on a model ecosystem (Australian Wet Tropics bioregion), known to be under threat from climate change (Williams, Bolitho & Fox 2003), and on a model taxonomic group (flying-foxes), known to be vulnerable to extreme heat events (e.g., Welbergen et al. 2008).
Our work at the Tolga Bat Hospital is part of our broader efforts to produce accurate estimates of the thermal sensitivity of the Wet Tropics vertebrates. The information will help us quantify the vulnerability of these animals to extreme temperature events, which is crucial for predicting the impacts of climate change on biodiversity and for preserving Australia’s unique natural ecosystems in this century and beyond.
References:
Williams, S. E., Bolitho, E. E. & Fox, S. 2003. Climate change in Australian tropical rainforests: an impending environmental catastrophe. Proceedings of the Royal Society B-Biological Sciences, 270, 1887-1892.
Welbergen, J. A., Klose, S. M., Markus, N. & Eby, P. 2008. Climate change and the effects of temperature extremes on Australian flying-foxes. Proceedings of the Royal Society B-Biological Sciences, 275, 419-425.
Go to the Animal Ecology Lab to learn more and see their heat stress forecaster. On our site, see how we cared for large numbers of Spectacled flying foxes after the 2018 Cairns heat stress event and read more about Heat Stress.
STRATEGIES USED TO BEAT THE HEAT
All photos courtesy of Dr Justin Wellbergen
Photo: (left) Panting
Photo: (above) Licking
Photo (right) Clumping Bats will come down out of the canopy and clump on to the shaded side of the trunk of the tree. The surface temperature of the bark is cooler than the air temperature.
Ina Smith, PhD
New and Emerging Zoonotic Diseases CSIRO, Australian Animal Health Laboratory, Geelong 2013
We collected 233 bat flies and 99 ticks during the 2012 tick season. They will be used to determine if they play a role in disease transmission in bats.
Australian Museum, Sydney 2013
The DNA laboratory at the Museum was involved in a national project to identify animals that come down as a result of plane strike. They requested DNA samples (wing biopsies) from 3 species of flying fox we have in care to help build a reliable DNA database on the four species of Australian flying fox. Plane strike usually results in only a blood smear/tissue of the animal from the plane.
David Westcott PHD
Ecosystem Sciences, CSIRO, Atherton 2010
- We provided some Spectacled flying foxes in our care with a diet that included markers to detemine how fast food is incorporated into the tissues of the animal, in this case hair.
- We provided 100 dead Spectacled flying foxes from the 2008 tick season for stable isotope research. All animals were found dying of tick paralysis and assessed to be non-viable for treatment. Analysis of the hair had some interesting results, showing that the diet of SFFs is quite variable.
Samantha Fox, James Cook University
Population Structure in the Spectacled Flying Fox, a study of genetic and demographic factors 2006
Supervisors: Drs David Blair, Michelle Waycott and Jon Luly from (JCU), Dr David Westcott from CSIRO
The project, involving the Queensland Parks and Wildlife Service, Queensland Fruit and Vegetable Growers, the Tolga Bat Hospital and JCU used genetic fingerprinting to attempt to trace the movements of the Spectacled flying-fox. Microsatellite and Amplified Fragment Length Polymorphism (AFLP) genetic markers were used to identify individual flying-foxes killed by tick paralysis. Some wild-caught bats were also used in the study.
The project also determined the age structure of SFFs from the Tolga colony dying as a result of tick paralysis. Canine teeth were taken from all dead bats over 2 tick paralysis seasons, and a cross-sectional analysis performed on the layers of cementum in the root of the tooth. The research is based on a paper published by Dr Simon Cool from the University of Queensland in 1994, Age Estimation of Pteropid Bats (Megachiroptera) from Hard Tissue Parameters.
Sam lived at the Bat Hospital for several months during the 2004 tick season. She accompanied us on searches in the camps, and when back at the hospital took teeth from the dead and euthanased, and wing biopsies from the dead and living.
After receiving her PhD, Sam Fox has spent her career working with Tasmanian Devils.
COLLARS
We have trialled tracking collars for a range of agencies – radiotracking, GPS and satellite. There have been problems with a lot of the collars causing skin damage during trials and even death out in the field. We urge all researchers to do extensive trials before using collars.
CSIRO staff trailing collars. The bats are anaesthetised so the collar can be measured and fitted satisfactorily.
Rubbing from the collar is a real issue. This sort of injury in the wild would slowly worsen and cause death.
This collar being trialled in our cage was a little too big and came off when it was caught, but is a much better outcome for the bat int he wild than if the collar was too small.
CSIRO staff trialling a GPS collar system.We have been involved with trialling collars with various technologies attached – radio tracking, GPS and satellite.
Flying-foxes that don’t cope mentally with the collar will repeatedly try to lick the collar but cannot reach it. The licking and excessive saliva results in hair loss after a couple of days.
Tasmin Rymer, James Cook University 2013
We will look at the consumption of salt by 4 Australian species of flying fox at the Tolga Bat Hospital. Stable isotope studies by CSIRO on Spectacled flying foxes have shown that mangrove provides about 13 % of their diet, and anecdotally flying foxes are frequently observed drinking from sea water and brackish water. Some institutions in USA provide flying floxes with salt licks but the Bat Hospital provides salt in drink bottles at the rate of 4 gms to 2 litres. Generally about twice as much salt water is comsumed conpared to fresh water. Both fresh and salt water bottles hang together so the choice is always theirs. The lids of the bottles are green for salt and red for fresh.
The only mention of this in the literature is a paper by Iudica and Bonaccorsro in Mammalia 2003 Anecdotal observations of sea water ingestion by flying foxes of the genus Pteropus.
Alexandra Coghlan, Department of Toursim, James Cook University
Towards an Understanding of the Volunteer Tourism Experience 2005
Supervisors: Primary Supervisor: Professor Philip Pearce, Secondary Supervisor: Dr. Laurie Murphy
A researcher with a strong interest in wildlife conservation, Ali completed a B.Sc. in environmental and marine biology at St-Andrews University, with an honours degree in ecotourism. Two years working as a guide for a whale-watching operation, followed by a third year working as a research assistant in the whale-watching industry prompted her to undertake a PhD degree in tourism, in an effort to link the two areas. By combining tourism and wildlife conservation, she hoped to gain public support for conservation and increase the personal relevance of wildlife protection for the general public.
The aim of her research was be to understand the expectations of volunteers, and the benefits they receive for their efforts. This understanding may help organisations build higher levels of volunteer involvement, satisfaction and commitment by matching the volunteer’s expected benefits and benefits that they provide. This would hopefully lead to a more sustained on-site conservation effort from volunteer tourists.
Research on volunteer tourism wass a relatively new area in 2004 and included few studies on the profile of volunteer tourists and the typology of volunteer tourism conservation organisations. Little was known about how volunteer tourists perceive their experience and how satisfaction with their experience affects their involvement with, and commitment to, conservation efforts. Understanding these elements is important as volunteers form the backbone of such organisations. By giving their time, energy and funds, volunteer tourists enable vital conservation projects to be carried out. In return, the tourists participate in a unique experience, develop new skills, discover a new way of life, and learn about themselves.
Ali used our volunteers for her pilot study, and came back a few months later to use us again for part of the main research. A number of other well-known volunteering conservation organisations around the world were included in the research project.
The aim of this study was to apply previous research of tourist and volunteer behaviour to the field of volunteer tourism in order to understand the expectations of volunteer tourists as well as the benefits they seek, and receive, for their efforts. The results of this research will help generate an even more sustained conservation effort from each conservation volunteer and a higher level of overall productivity, benefiting your organisation and conservation efforts in general.
• Help to promote the efforts of conservation organisations, such as Tolga Bat Hospital.
Epidemiology of tick paralysis in spectacled flying-foxes (Pteropus conspicillatus) on the Atherton Tableland,Further information is available at the website, search Alexandra Coghlan http://www.jcu.edu.au