It’s spring in Queensland, Australia, a time when many wild animals find themselves in trouble, and the Currumbin Wildlife Hospital is a blur of fur and fur.
A groggy black swan emerged from the X-ray room, its head swinging from its long neck. A flying fox wears a small anesthetic mask. An injured rainbow lorikeet jumped out of its cage. (“Infuriated,” one sign warned.)
“We see everything,” Dr. Michael Pyne, the hospital’s senior veterinarian. Also on the schedule for the day: three eagles, two carpet pythons, a blue-faced honeyeater, a short-eared brushtail possum and, said Dr. Pyne, “a whole heap of koalas.”
More than a dozen koalas are recuperating in open-air enclosures, wrapping their thick arms around the trunks of eucalyptus trees. Wards are often full; in 2023, the hospital admitted more than 400 koalas, a fourfold increase since 2010.
The climb is largely driven by the spread of chlamydia, a devastating bacterial infection. But the hospital is also seeing more koalas with traumatic injuries, including those caused by cars and dogs. Hungry, dehydrated koalas enter the dry season; charred koalas appear after wildfires. Occasionally, koalas even arrive with injuries caused by cattle.
“That’s why they’re endangered,” said Dr. Pyne. “Everything is against them.”
The koala, long an icon of Australia, has become an unfortunate symbol of the country’s biodiversity crisis. Animals are threatened by deforestation, climate change and infectious diseases. Together, these forces keep the koala moving the real danger of extinction. Although koalas are notoriously difficult to count, populations in some areas have plummeted by up to 80 percentscientists estimate.
“We don’t know what the threshold is beyond which there is no return,” said Tanya Pritchard, the senior manager for species recovery and landscape restoration at the World Wide Fund for Nature-Australia. “So we need to act urgently.”
Scientists and conservation groups are giving the koala everything they have. Some are taking traditional, time-tested strategies, including protecting koala habitats and advocating for stricter conservation laws.
Others are trying more experimental approaches, from koala probiotics to tree-planting drones. Many of these projects are in early stages, and none represent a complete solution. But given the wide range of threats the koala faces, saving them may require deploying every available tool.
“At this point,” said Ms. Pritchard, “every koala is important.”
Here are some of the development tools.
Put shots in the arms
Chlamydia, a common sexually transmitted infection in humans, is also prevalent in the animal kingdom. How the koala first became infected is unknown, but one possibility is that the marsupials picked up the chlamydia from the animals’ feces.
The disease, which can be spread sexually and from mothers to joeys, has become very widespread in parts of Australia. Chlamydia can cause urinary tract infections, blindness and infertility, suggesting koalas may be in worse shape than their declining numbers. “How many of the koalas out there can’t breed because chlamydia has made them sterile?” Said Dr. Pyne.
Scientists are now working with the Currumbin Wildlife Hospital in Currumbin, Australia, to try a new chlamydia vaccine in the wild koala. So far, the vaccine is producing “pretty amazing results,” said Ken Beagley, an immunologist at the Queensland University of Technology who led vaccine development.
In two ongoing studies, more than 300 wild koalas have been vaccinated, and many vaccinated females have had healthy joeys, some of whom have gone on to have joeys of their own, said Dr. Beagley. “It was better than we expected,” he said of the outcome.
However, it would be difficult to inoculate thousands of wild koalas with the current vaccine, which requires two shots given 30 days apart. So Dr. Beagley and his colleagues developed a delayed-release vaccine implant, which can be injected under the skin when the koala receives its first shot. Over several weeks, the small capsule slowly absorbs water and then bursts, thus delivering a second dose.
Give them good germs
Koalas are notoriously picky eaters with a very unique taste. “They feed on a really unpalatable diet of eucalyptus leaves, which is high in fiber, low in protein, high in toxins,” said Michaela Blyton, a molecular ecologist and microbiologist at the University of Queensland.
Living in eucalyptus requires a cooperative community of gut microbes, which help digest the leaves. The work of Dr. Blyton suggests that these microbial communities are so finely tuned that they can dictate which type of eucalyptus, among the many that dot Australia, an individual koala can eat. That microbial specificity may explain why koalas are sometimes unable to diversify their diets, even in the face of starvation.
In a 2019 study, Dr. Blyton that he could transfer koala microbiomes, and expand their diets, by giving them fecal transplants from koalas that feed on other types of eucalyptus. (To perform the transplant, Dr. Blyton packaged fecal samples from the donor koala in small capsules, which were administered orally.)
Now, he hopes to use the same approach to maintain microbial equilibrium in koalas taking antibiotics, which are the frontline treatment for chlamydia. Drugs can throw off the gut microbiome, prompting koalas to stop eating altogether, with sometimes fatal results. “It’s hard to ask the animal to work again, and often we can’t,” said Dr. Blyton, which works with Currumbin and other wildlife hospitals.
Dr. Blyton has developed a technique for freeze-drying fecal samples from healthy koalas, yielding shelf-stable capsules that can be given to koalas with chlamydia as a type of oral probiotic. Unfortunately, early trial results suggested that administering the capsules was stressful for the sick koala. So now Dr. is trying. Blyton turned the dried fecal sample into a powder that could be added to other nutritional supplements the animals were already receiving.
Deploy the drones
Koalas — sedentary, living in trees — are difficult to spot in the wild, adding to the challenges of monitoring how their population is doing, identifying critical habitats and protecting the animals from threats.
Grant Hamilton, a quantitative ecologist at the Queensland University of Technology, has developed a new one koala-spotting system powered by artificial intelligence. A drone equipped with a thermal camera flies over the treetops, looking for pockets of body heat hidden beneath the canopy. Machine learning algorithms can quickly process this footage, analyzing the koalas. Scientists use statistical models to estimate the total koala population in a given area.
Scientists are now teaching local conservation groups how to fly drones in their own neighborhoods. Dr. will examine Hamilton and his colleagues used the data to help these organizations identify critical koala habitats that could benefit from protection or restoration. “We can use AI to help people manage their backyards or their parks,” he said. “That’s a really exciting idea.”
The World Wide Fund for Nature-Australia, which is currently running a campaign on save or plant two billion trees by 2030, is experimenting with using drones for habitat restoration. Over the course of eight hours, a tree-planting drone can rain about 40,000 seeds across the landscape.
Drones aren’t suitable for all environments, but they offer a way to “magnify this work,” Ms. Pritchard. “For me, this is a small symbol of our own condition,” he added. “If we can’t save the koala, as our most precious and beloved species, what does that mean for our own situation and the health of our own habitats?”
Harness solar (and human) power
Despite the threats they face, the koala has something for them. “They are one of the cutest animals on Earth,” said Dr. Romane Cristescu, a conservation ecologist at the University of the Sunshine Coast.
To capitalize on the public’s natural love of koalas, he and his colleagues are developing a range of technological tools, including solar-powered, location-tracking ear tags, which transmit data to a mobile app. The app, which is still undergoing testing, aims to help Australians identify koalas living in their neighborhoods — “where they go, who they meet, their kids, their boyfriend,” it said. by Dr. Cristescu. “We’ll tell people, ‘Hey, look, that koala is alive.’”
Dr. expects Cristescu that people who develop an attachment to their local koala will be more inclined to support conservation efforts and change their own behaviors, such as choosing not to cut down trees in their yards. “We have a lot of empathy for a koala with a name and a story,” he said.
The app also encourages users to log koala sightings and report sick koalas, data that can be sent to scientists and wildlife care teams, he said.
Ear tags can be used for other purposes as well, says Dr. Cristescu, who is also leading a research program that uses trained dogs to sniff koalas and koala scat. After the catastrophic wildfires in Australia in 2019 and 2020, his team used dog and drone to find and rescue injured koalas. Location-tracking ear tags could provide a faster way to find koalas at risk, he said.
