It was spring in Queensland, Australia, a time when many wildlife are in trouble, and the Currumbin Wildlife Hospital was a blur of fur and feathers.
A tanned black swan emerged from the X-ray room, head bobbing on its long neck. A flying fox wore a tiny anesthetic mask. An injured rainbow lorikeet squabbled in its cage. (“Very angry,” a sign warned.)
“We see everything,” Dr. Michael Pine, the hospital’s senior veterinarian. Also on the day’s schedule: three eagles, two carpet pythons, a teal-faced honeyeater, a short-eared possum and, Dr. Pine said, “a whole bunch of koalas.”
More than a dozen koalas were recuperating in outdoor facilities, wrapping their woolly arms around the trunks of eucalyptus trees. The wards were often full. in 2023, the hospital received more than 400 koalas, a fourfold increase since 2010.
The surge is largely due to the spread of chlamydia, a devastating bacterial infection. But the hospital was also seeing more koalas with traumatic injuries, including those caused by cars and dogs. The hungry, dehydrated koalas came during the drought. burnt koalas appeared after wildfires. Occasionally, koalas were even seen with injuries caused by cows.
“That’s why they’re at risk,” said Dr. Pine. “Everything is against them.”
The koala, long a symbol of Australia, has become an unfortunate emblem of the country’s biodiversity crisis. Animals are threatened by deforestation, climate change and infectious diseases. Together, these forces put the koala the real risk of extinction. Although koalas are notoriously difficult to count, populations in some places have plummeted up to 80 percentscientists estimate.
“We don’t know what the point of no return is,” said Tanya Pritchard, senior manager of species recovery and landscape restoration at the World Wide Fund for Nature-Australia. “So we have to act quite urgently.”
Scientists and conservation groups are giving the koala everything they have. Some follow traditional, time-tested strategies, including protecting koala habitats and advocating for stricter conservation laws.
Others are trying more experimental approaches, from probiotic koalas to tree-planting drones. Many of these projects are in early stages and none is a complete solution. But given the wide range of threats koalas face, saving them may require deploying every available tool.
“At this point,” Ms Pritchard said, “every koala counts.”
Here are some of the tools in progress.
Put shots in the hands
Chlamydia, a common sexually transmitted infection in humans, is also widespread in the animal kingdom. How the koalas first became infected is unknown, but one possibility is that the marsupials picked up chlamydia from the animals’ feces.
The disease, which can be spread sexually and from mothers to joeys, has become surprisingly widespread in parts of Australia. Chlamydia can cause urinary tract infections, blindness and infertility, suggesting koalas could be in even worse shape than their declining numbers would suggest. “How many of these koalas out there can no longer reproduce because chlamydia has made them sterile?” said Dr. Pine.
Scientists are now working with Currumbin Wildlife Hospital in Currumbin, Australia to test new chlamydia vaccine in wild koalas. So far, the vaccine is producing “pretty spectacular results,” said Ken Beagley, an immunologist at the Queensland University of Technology who led the vaccine’s development.
In two ongoing studies, more than 300 wild koalas have been vaccinated, and many vaccinated females have gone on to have healthy cubs, some of whom now have cubs of their own, Dr Bigley said. “It was much better than we expected,” he said of the result.
However, it will be difficult to vaccinate thousands of wild koalas with the current vaccine, which requires two shots 30 days apart. So Dr. Beagley and his colleagues are developing one delayed release vaccine implant, which could be injected under the skin when a koala receives its first shot. Over several weeks, the small capsule would slowly absorb water and then burst, giving the second dose.
Give them the good germs
Koalas are notoriously picky eaters with highly unusual tastes. “They feed on a really nasty 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 with 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 may dictate which species of eucalyptus, of the many that exist in Australia, an individual koala can eat. This microbial specificity could explain why koalas are sometimes unable to diversify their diets, even in the face of starvation.
In a 2019 study, Dr Blyton showed she could shift the microbiomes of koalas and expand their diet, giving them transplants of feces from koalas that dined on a different type of eucalyptus. (To perform the transplant, Dr. Blyton packaged stool samples from donor koalas into small capsules, which were administered orally.)
Now, he hopes to use the same approach to maintain microbial balance in koalas receiving antibiotics, which are the first line of treatment for chlamydia. The drugs can wipe out the gut microbiome, prompting koalas to stop eating altogether, with sometimes fatal results. “It’s hard to get the animal to start again, and a lot of times we can’t,” said Dr Blyton, who works with Currumbin and other wildlife hospitals.
Dr Blyton has developed a technique to freeze-dry stool samples from healthy koalas, yielding shelf-stable capsules that can be given to koalas with chlamydia as a type of oral probiotic. Unfortunately, early test results showed that administering the capsules was stressful for the sick koalas. So Dr Blyton is now trying to turn the freeze-dried faecal samples into a powder that could be added to other nutritional supplements the animals are already receiving.
Deploy the drones
Koalas – sedentary animals that live in trees – are difficult to track in the wild, adding to the challenges of tracking their populations, identifying critical habitat and protecting the animals from threats.
Grant Hamilton, a quantitative ecologist at the Queensland University of Technology, developed a new one koala tracking system powered by artificial intelligence. A drone equipped with a thermal camera flies above the treetops, searching for pockets of body heat hidden beneath the canopy. Machine learning algorithms can quickly process this video, counting the koalas. Scientists then use statistical models to estimate the total koala population in a given area.
Scientists are now teaching local conservation groups how to fly the drones in their neighborhoods. Dr Hamilton and his colleagues will then analyze the data to help these organizations identify critical koala habitats that may benefit from protection or restoration. “We can use artificial intelligence to help people manage their yards or their parks,” he said. “This is a really exciting idea.”
The World Wide Fund for Nature-Australia, which is currently campaigning for save or plant two billion trees by 2030, is experimenting with using drones to restore habitats. Over the course of eight hours, a single tree-planting drone can rain about 40,000 seeds across the landscape.
Drones are not suitable for all environments, but they offer a way to “upgrade that work”, Ms Pritchard said. “To me, it’s a bit symbolic of our own misery,” he added. “If we can’t save the koala, as our most important and most beloved species, what does that mean for our own condition and the health of our own habitats?”
Harness solar energy (and people).
Despite the threats they face, koalas have one thing in common. “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 affection for koalas, she and her colleagues are developing a range of technological tools, including solar-powered location-sensing headphones that send data to a mobile app. The app, which is still being tested, aims to help Australians get to know the koalas living in their neighborhoods – “where they go, who they meet, their kids, their boyfriend,” Dr Cristescu said. “We’ll tell people, ‘Hey, look, this koala has life.’
Dr. Cristescu hopes that people who develop attachments to their local koalas will be more willing to support conservation efforts and change their own behaviors, such as choosing not to cut down trees in their backyards. “We have a lot more empathy for a koala that has 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 groups, he said.
The ears could be used for other purposes, said Dr. Cristescu, who also leads a research program using trained dogs to smell koalas and koala shit. After Australia’s devastating wildfires in 2019 and 2020, her team used dogs and drones find and rescue injured koalas. Positioning headsets could provide a faster way to find koalas in distress, he said.