Koalas: Braving the Australian Bushfires

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Speaker 1: Hi, I'm Ebony Money and I'm Rich Schwartz. Welcome to Amazing Wildlife, where we explore unique stories of wildlife from around the world and uncover fascinating animal facts. This podcast is a production of I Heart Radio and the San Diego Zoo Wildlife Alliance, an international nonprofit conservation organization which oversees the San Diego Zoo and Safari Park. Today, we're going to take a virtual trip to Australia, the only place where a very special arboreal marsupio can be found, and we will find out what our conservation ally Science for Wildlife is doing to better understand this species and save them in the wild. I'm so excited to learn more about one of the most iconic animals in Australia, the koala. Where exactly in Australia are they found? Yeah, you know, Astralia is a pretty big place and so it's important to understand they're only found in certain regions, and that area would be the eastern and southeastern portions of Australia. So this would include the state of Queensland, New South Wales and then a little bit west into the state of South Australia. So Rick I hear Koalas are very picky eaters. What exactly to kuala is eat and how are they fed? Yes, Koalas are finnicky eaters in fact that they rely on a single source of food. One I could almost say it would be like eating the same cereal day in and day out for your entire life. They eat only eucalyptus. Now, there has been some recordings of them eating a little bit of other trees or leaves from other trees, but it's so minor the amount that they really consider them just eucalyptus eaters. Now, that said, there are over nine species of eucalyptus in the area, but everything's kind of reported from what we've observed and seen, they only eat about seventy different species. And of those seventy species of eucalyptus they eat, it will depend on season and location is to which speed sees are going to be tasty for them. Now, we assume that has to do with the minerals and the different tannins and oils that are found in eucalyptus and what's going to be either most nutritious or flavorful for them. That being said, eucalyptus is also high in toxicity for many other species, So it might have to do with the levels of whatever toxic chemicals are in there. Maybe certain times you're are best or less threatening, I should say for the koala and so are Koala is very unique in that they're just born able to digest the eucalyptus leaves or is there a process that happens. Yeah, a lot of people don't realize that leaf eating or high fiber diets or only fiber diets. So this would be your grazers, those that eat like grasses and small but plants on the ground, and then their browsers eating trees and bushes and things like that. All that fiber you have to have a special sort of bacteria in your gut to help break that down to digest the nutrients out of it. And in fact, with koalas they sleep quite a bit because they they want to spend their time and energy looking for food, digesting food, or resting from all that activity. So that's how hard it is. So when they are first born, they don't have that bacteria in their gut. So a baby as it's nursing mom will also create what's called pap and the baby has to eat this and this basically is the bacteria from mom's gut going into the baby's mouth and into the gut then for them, and it allows them to start growing that what they call a flora or a growth of bacteria in the gut, which will then help them break down that tough fiber of the eucalyptus, a very important step for a baby Koala. Rick. So, how long do the Joey's or baby Koala's stay with their moms after weaning? Yeah, so, for for Koala Joeys, staying with mom is pretty much their best bet, you know, being in that pouch when they're first born and being raised up there. But they'll leave that pouch as they get too big for it around seven to eight months of age, and they don't become truly independent from mom and until that winning process starts there at about twelve months to twenty four months of age. Even then, when they do leave mom's side, they'll remain close by for the next few months, maybe the tree next door, a couple of branches down, whatever it may be. Now the males, though, when they do start to become more independent and they do start breaking away from mom's territory. They will leave that natal territory, that home range that they're born into, and kind of go off and establish their own space and territory where the female offspring tend to set up a home range nearby. Mom. So, Rick, you mentioned the different species of eucalyptus. We have koalas at the San Diego Zoo. How do wild life care specialists feed the kuala is there? It is quite a process, and sometimes I think when we think of animal care, we think of just the wildlife care specialists doing the work with them, but with koala's it involves an entire team of horticulturists as well. Now we're very lucky here in San Diego we can grow our own eucalyptus and many many different species. We have a whole eucalyptus farm just for our koalas. So it's pretty fascinating to think that a horticulture team goes out to harvest this fresh it gets bundled up and sent to the zoo directly right here in San Diego. And then our wildlife care specialists go through and pick out different bundles of different species and offer multiple times throughout the day different species to our koalas and they get to snack on it as they see fit. And speaking of the different species of the eucalyptus, are the different types of eucalyptus responsible for the lethargic way that koalas seemed to behave, you know. And it's funny you mentioned that because a lot of people used to have this sort of idea that the toxic chemicals in eucalyptus it's very dangerous for all other species. People assume that somehow the koalas could manage this toxicity, but it kind of comes across and making them sort of you know, dazed and glazed and always kind of you know, sleepy. But as we move forward with understanding science better, we now know that it's just because they have to spend so much energy breaking down the tough fiber of eucalyptus that they sleep a lot. They move slow elite. Now I'll tell you what I have seen though, if they feel challenged, they can move really quickly when they want to. So it's not that they are in they're sort of a toxic haze, if you will, from the eucalyptus. It's just that their body is set up to spend most of its energy slowly grazing on this eucalyptus at nighttime and then digesting it while they sleep. Now, speaking of misconceptions, for a long time people thought that are referred to Kuala's as bears, but they are not bears. What makes them different and unique than bears? Oh, it's pretty straightforward. They lack the coualification to be a bear, meaning, so they are marsupials. Being a marsupial means not that you have a pouch. It means that you're raised in a pouch. So sometimes stories and cartoons have us believed that the pouches used to hold all sorts of things in both males and females. Have it just the females have pouches, But everybody who's a marsupial was raised in a pouch. So that could be a koala, kangaroo, opossum, a wombat, Tasmanian devil. They're all marsupials. And what really kind of helps clarify that definition is when they're born, they are terribly underdeveloped, very very small, some of them no bigger than a grain of rice, some about the size of a jelly bean, depending upon what species you're talking about. They have to climb in from the birth canal into the pouch and then they latch on there and spend the first few months of their life in that pouch. You'll never see them again until they poked her head out around, depending again on the species, five to six, sometimes seven or eight months of age. Thanks Rick, I'm glad we were able to clear that up. Absolutely my pleasure. All right, now, it's time for the San Diego Zoo Safari Park Minute, an opportunity for you to learn what's new at the zoo. San Diego Zoo recently opened Komodo Kingdom, which offers you the chance to see the world's largest lizard, the captivating Komodo dragon. Did you know that Most lizards are omnivores, eating both plants and meat, but the Komodo dragon seeks prey. Their bite is toxic, and if their prey escapes, the lizard follows it at a leisurely pace. That's because the dragon's bite contains a deadly bacteria that will eventually kill its intended meal. You're listening to amazing wildlife. We'll be right back in. There was a period referred to as the Black summer when brush fires burned in Australia. But what happens to the animals when these fires take place? A group of San Diego Zoo Wildlife Alliance researchers worked quickly to save dozens of Kualas in the Blue Mountains region. This includes Dr Kelly Lee and her Science for Wildlife team, who have been very important long term partners of San Diego Zoo Wildlife Alliance. Doctor Lee is here to tell us about the rescuer. Dr Lee. It's not every day that we hear about scientists performing rescuers. Can you tell us about the days leading up to that decision? Yeah? Absolutely, you're right. It's not something we normally do so as research as we focus on conserving wildlife at the population level. And I guess seeing the scale and extent of these fires was what drove some fairly desperate action on our part. I guess fire is a natural part of the landscape here, but it was really clear watching these black summer fires that you know they were weather driven. The fires were behaving in a way that had never been seen before. They were covering of the Greater Blue Mountains World Heritage Area, which is a million hectares insides, which I think is about two and a half million acres in size, and so that's what drove our decision to you know, we've just got to go in and fry and save some animals. And we've been studying glas in this area for It was all pretty rapid, I have to say, I had two days to pull this entire operation together, so part of it was also waiting for approval and then waiting to know if we had the right conditions where we could go in safely to get these koala's out. So two days to prepare. How did the researchers prepare to go into the region. So we had our ecologists. We also had a great team of volunteers who were part of our team who were regularly radio tracking a lot of these koalas with us. And I also pulled up an expert koala capture team from Victoria from Interstate, so they flew up to help pull the koala's down out of the trees. So they're pretty tricky things to catch the koala, So a lot of safety prep and setting up a station sort of in the middle of the bush where we could bring the koalas to to check them out go to organize transport. We had the zoo down in Sydney that we're preparing to take them. Nobody was really prepared for something of this scale. There was a lot of logistics really, and then making sure everybody could get up there and get to sign it on the morning and spend the two days needed out there with us. What can you tell us about the conditions at the time, in in the terrain and any limitations you faced. The fires were massive and there was three around this area. So if you're driving down the main road through the Blue Mountains, you could see like massive clouds of smoke, these huge weather systems in three different directions. I remember when I evacuated my house. You know, the firefront was quite close to me at that time, so I was in thick smoke and falling ash. I had a mask on and I was trying to prepare my house before evacuating it. Um, So it was all it was all pretty confronting stuff. It was satisfying to get out, I guess, and to just do some action, do something and try and help some wildlife. So can you talk to me about how you were able to locate the koalas and how they responded to being you said, physically pulled out of trees. So we had some coals that we've been radio tracking already in that area um and so we focused on you know, I had several teams of people. I had a team going out for two teams going out radio tracking the coala's that we had tags on, and we were hoping that they hadn't gone too far. Because the terrain is really steep. You can spend up to a day, like seven or eight hours tracking one koala and obviously if we only had two days, that was going to be a push to get any animals out, but foculing most of them were up around the ridge line and not too far away, So we had radio tracking teams out and then I had another line of people when we're trying to find koala's, you know, to catch them and give them a health check and then follow them, which is part of our research. We set up it's like a search and rescue line through the bush. So we have people spread out in a line with radios at either end, keeping in touch and just moving so early and doing a visual search of the canopy. So I had a team out trying to look for koala's that we didn't have radio tags on in case we could get some extra animals as well as the teams that were out radio tracking the koala's we had. Then I had another team of people going out and collecting brows. So the brows is basically the branches that you feed the koalas, and that's a huge job. Like koala is actually really difficult to keep in captivity because they're very fussy eaters. You need to collect three or four different species of tree every day. For every koala, you've also got to keep it wet. If it's out of water for more than an hour, they might not eat it. So that was following on. That was a big job. But on on the day obviously we wanted to send them down with some local food as well. And so then if we if the radio tracking teams found the koalas, then we go and assess it to see if the tree was climbable. So yeah, then we'd send out climbers in who go up. And the way you get a koala down out of a tree is you sort of bother it down the tree. You you they have this response to if you you basically have an extendable pole with a flag on it. The flag is just a bit of fabric essentially, and you wave it above the koala's head and the koala doesn't like it, and so it starts coming down the tree, and you can do it quite gently, you do it depending on the koala. Some are a bit resistant. Some of the males might try and grab the flag or bite it or fight it and not come down the tree. Others will just look at it and start slowly coming down. So we've got some really experienced climbers who can read the koala's behavior really well, and they just lead them down, you know, it's fairly low stress. And then once they get to the bottom, we grab them and put them in a sack, which is a little bit like being in a pouch, I guess, and they seem to calm down, so then we put the sack over the shoulder essentially and carry them out and then I'd set up a station in the middle with some water, obviously, because it was really hot weather driving these fires and we needed to be careful of heat stressed with the koalas, so we check them out, check them for panting, make sure they had water, and then we also had people sort of standing by to transport them, so they go straight into an air cognition car and as soon as we had a couple of koalas would send them off down to the zoo. We did manage to get most of out tagged animals out as well as a couple of extras and get them down to the zoo. Congratulations on that. So you were researching the koalas of this region prior to the fires, Can you talk about the significance of that koala population. Yeah? Absolutely, and I guess that was something that that justified the rescue as well. When we were trying to get permission, we had uncovered this incredible story in the Blue Mountains here. So the Blue Mountains itself is pretty famous for big sandstone cliff lines, so it's it's famous sandstone country, and Koalas are well renowned for liking really nice soil types. So prior to our work here, everybody thought, well, Koala's just don't exist in the Blue Mountains, and if they do, there's not going to be many of them, there won't be any important populations. But what we found actually is a lot of koalas and a lot of rule breaking koalas who haven't read the literature on how koa's supposed to behave, So we were uncovering a whole bunch of different populations. Everywhere we looked. Essentially, we kept finding koalas, and in fact, at this particular site where we took the koala's out. It's funny like I go to research workshops and conferences and people do modeling, and a couple of the things that have come up is, one is a climate envelope for koalas, and coal should occur at eight hundred meters and below, and the koalas we were studying are at one thousand, two hundred meters and they get snowed on in winter. There's another particular tree species called the silver top ash, which some researchers have modeled and said, right wherever that tree species occurs, you won't find koala's. You know, the more of those trees, the less kalas. And yet that's a favored tree up on these sandstone ridge lines. We have coals that eat it and love it at two of our study sites. And I guess one of the more important things is that we did a big collaborative study with San Diego Zoo, Wildlife Alliance UM and James Cook University in Sydney UNI, and we looked at the genetic diversity of Koala's right across the species range UM and we only had a few samples I think about twenty from the Blue Mountains region and they came up as having the highest genetic diversity in the country. And reason that's important is the more diversity you have, the more likely that kalas can adapt to selection pressures over time, so you know, it enables them to persist over time in the landscape, and so you really want to conserve whatever diversity you have left. And then also we had some that are essentially disease free, so chlamydia is a really important disease. It impacts koala is quite badly across their range. A lot of populations are in decline because of that disease. But this is the second population in New South Wales that we found that's free from flamidia. I guess one of the other things about this area is that it's the World Heritage Area partly because of the huge diversity of eucalypts will get here. So there's around a hundred of different species of eucalypt or gum tree, which gives these coalas more food choice than anywhere else in the country as well. Know, by studying them here we can work out, well, why do they select certain trees to eat, you know, what are their limits and the types of habitats they can use um and how are they going to persist under climate and so so it's been a really fascinating area. And because of that, we had this amazing story of hope. You know, we had coala's inside a protected area system, populations that were growing higher, genetic diversity, disease free um and then these fires came through and just they've completely changed that picture. Amazing work. What would you say it would be the significance of this this rescue mission for the overall objective to see the choir? Yeah, look it's I mean we ended up getting out twelve koalas, so it was limited in terms of how many of the zoo could take and also brows storage, so basically they you have to put the brows in buckets in a cold room and they could only fit so much. So they said we can I think they said we can only take ten koalas. But I figured, well, some of them are young joeys and only eight half as much, so we took in twelve eight adults and four youngsters, and then one of them ended up having a joey. She we did a pouch check when we caught her and she had been breeding every year. We didn't see a joey in the pouch, but she'd already conceived. So when we released them, were put thirteen back, which was nice, and we had an extra. But yeah, so in terms of the number of Koala's it's not massive, but in terms of having the gene pool there, it was a really good backup. It's also been really useful to them. After we released them, we waited till the conditions improved and so we decided it was okay to put them back, and then from then on we've been radio tracking them and they've been showing us how Koala's used to landscape after fire. So the area put them into was it was mostly low intensity fire. Some of the patches were hit a bit harder, but for instance, their home ranges have doubled in size, and that's a concern because Koalas are they've got quite a fine energetic balance. Because they spent a lot of energy digesting their food. You know, Eucalyptus leaves toxic to most animals, and people say Koala's look a bit stoned or a bit drunk. That's kind of a bit of a legend about Kala's, But they're not, obviously, they're just sitting there looking dozy because all their energy is going to digesting those eucalypt leaves, and so there's this fine balance between the amount of time they spend moving and using energy and then you know, getting to the to the food and then digesting that food. So at the moment they're all looking okay, but that long term monitoring is really important to see those impacts. We've also been able to discover that they can eat the young shoots of eu collects after fire um so it's called epicormic growth. And basically one of the adaptations of gum trees is you get these little shoots coming straight out of the main trunk or the big branches um so the tree almost looks fluffy. It gets just gets covered in all these young leaves. And we didn't know if colas could eat that because the main way that trees in Australia defend themselves is chemicals, so they'll put all these tannins and things in the leaves that make it unpalatable and undigestible to koalas. And we thought, if it's new growth, you know, it's going to have a lot of chemical defenses in it, the colas may not be able to eat it. But that hasn't been the case. Um, They've actually been attracted to it and thriving off it. So so that's actually a really you know, it's a it's a hopeful thing that in areas that have been burnt, once they're safe for the koalas to move through, they can consume this epicuomic growth and survive off it. Thanks fassinating. So what can people at home do if they want to help? We always need resources, and particularly because we need to do this long term monitoring now, like if we find koala's, we want to see what they're breeding rates are, like if the populations are growing or declining um and manage threats. So, you know, raising awareness is really important too. I think Australians have kind of taken for granted that we'd have koalas around for a long time, and certainly the way things are looking at the moment, it's a species it's really under threat. So so just having conversations with other people and raising that awareness is really important. You know. We do a lot of that here with the local communities. You know, we want people to get involved in conservation. So aside from our research, once we've got all of the results in UM, the first round of which would be soon abe early next year, we'll be mapping corridor areas, which include developed areas around communities. So we're going to be inviting people to you know, to plant trades on their properties to restore corridors and connectivity and and so yeah, efforts have got to be multifascinated our guests in terms of we need the information to guide the action, we need the on round action, and we need resources to support it as well. And the more awareness we have the better. Dr Kelly Lee, Executive director of Science for Wildlife in Australia, thank you so much. Thanks very much, And if you would like to help San Diego Zoo Wildlife Alliances work with koalas with partners such as Science for Wildlife, please go to sdz W a dot org. I'm so happy we were able to save those adorable Koalas. Thanks for listening to today's show. We hope we learned a lot and are inspired to do your part. Be sure to subscribe and tune into next week's episode, in which will bring you the story of the smallest mammal on the planet that hibernates and our efforts to save it. I'm Eppie Money and I'm Rick Schwartz. Thanks for listening. For more information about the San Diego Zoo in San Diego Zoo Safari Park, go to sdz w a dot org. Amazing Wildlife is a production of I Heart Radio. Our producer is Mikia Swinton and our executive producer is Marci the Peanut. Our sound designer and editor is Cody Scully, with assistance from Matt Stillo. For more shows from my heart Radio, check out the I Heart Radio app, Apple podcast, or wherever you listen to your favorite shows.