Did you know that as a group, amphibians are the most threatened vertebrates on Earth? As many as 1/3 are considered threatened.
As a result of this, my guest, Dr. Kerry Kriger, has devoted his education and career to amphibian research and protection. Dr. Kriger has a PhD in Environmental Science from Griffith University, and in 2008 founded of Save The Frogs! – the first global organization devoted to protecting amphibian populations.
As is often the case, we covered a lot of ground in today’s discussion! We start with Dr. Kriger’s research into the devastating Chytrid fungus and its impact on amphibians. Dr. Kriger points out that Chytridial mycosis is the worst disease in history in terms of biodiversity loss.
We take a few steps back and discuss amphibian diversity and lifecycles, the impact of hydro-periods ranging from permanent water to seasonal pools, frog dispersal and mobility, vocalizations, and more. And did you know that frogs are called gape-limited predators? Meaning, if it fits in their mouth, it’s fair game. I just love that concept and term!
Dr. Kriger also discusses other treats to amphibians, including habitat loss, climate change, and the challenges with American Bullfrog importation and their spreading to non-native locations. For example, American Bullfrogs are not native to the American West, and have had a huge impact on western amphibian populations.
Dr. Kriger fills us in on a huge variety of projects, outreach, tours, and more that Save The Frogs! offers. If you want to create habitat, go on an ecotour, or simply get inspired by amphibians, check out savethefrogs.com. Dr. Kriger has personally developed many educational resources as well, and offers 28 days of free access to his deep-dive content in the Frog Academy.
Did you have a question that I didn’t ask? Let me know at email@example.com, and I’ll try to get an answer! I’ll add these Q&As to my monthly newsletter, so if you aren’t already subscribed, go here. I promise, no spam. I share the latest news from the world of Nature’s Archive, as well as pointers to new naturalist finds that have crossed my radar, like podcasts, books, websites, and more.
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Links To Topics Discussed
People, Organizations, and More
Save the Frogs Day: April 28, 2023. It’s an annual event!
Save the Frogs! Academy – get 28 days free access
Books and Resources
Frogs: The Thin Green Line – documentary from PBS Nature
Cosmos – by Carl Sagan. A Classic.
Desert Solitaire: A Season in the Wilderness – by Edward Abbey
On the Origin of Species – by Charles Darwin
Note: links to books are affiliate links
Opening – Fearless First by Kevin MacLoed
Closing – Beauty Flow by Kevin MacLoed
Both can be obtained from https://incompetech.filmmusic.io/
Transcripts are automatically created, and are about 95% accurate. Apologies for any errors.
[00:00:00] Michael Hawk: Dr. Kriger, thank you for joining me today.
[00:00:02] Dr. Kerry Kriger: It’s great to be here. Thanks for having.
[00:00:04] Michael Hawk: People like you are the primary reasons why I started this podcast because there is just so much to learn in the world of nature. And I only have a very superficial knowledge of frogs, and I have this wonderful opportunity to talk to an expert, a global expert, nonetheless, on the topic.
[00:00:21] So super excited about that and what I was hoping to do, Kickstart a little bit is let’s just celebrate frogs for a moment. And the wonder that our frogs and we could probably start with basically, what was it that hooked you into the world of amphibians and frogs and the first.
[00:00:41] Dr. Kerry Kriger: To go way back. It was probably hearing frogs call. I grew up right near a pond. Actually, my parents built upon when I was young, so on the property we had lots of frogs still do fortunately. And. I hear all the frogs calling. I didn’t think too much about them, but I’m sure it went into my subconscious. And then later in life, I did gain a significant appreciation of the outdoors and nature and wildlife.
[00:01:11] And that came primarily from traveling all around the world and camping out, visiting national parks, spending a lot of time in nature. And from that experience, I also saw a lot of environmental destruction. If you go outside of the national parks, there would always be destruction. And I wanted to do something about that.
[00:01:32] I really like the peaceful feeling that I get when I’m out in nature. And I think it’s really important to people, to it’s important to me, it’s important to people in general. And aside from that, the nature. The wildlife has a right to exist as well, outside of whatever we want in the world. So lots of reasons to save nature and wildlife.
[00:01:54] And I think it mainly just goes back to spending a lot of time outside. I didn’t have a n actual frog fascination. When I was growing up though, I would certainly see them hanging out at the pond. I also grew up near a river and I’d spend time fishing down there and just hiking up the river, walking in the river, seeing crayfish and frogs and all the wildlife that hangs out around streams.
[00:02:20] And I also, I love hanging out at streams for whatever reason. When I did get interested in environmental careers, actually doing something professionally for the environment, I had to think about what am I going to do? And there’s a lot of different things one could do. And what came to mind was I really liked streams.
[00:02:39] What can I do at streams? And I found out that amphibians were rapidly disappearing, so that all just fit together perfectly.
[00:02:47] Michael Hawk: So it sounds like the close access to a couple of bodies of water was really key to focus you on the amphibians, as opposed to say the birds or the mammals or other things that perhaps were also in those same investors.
[00:03:01] Dr. Kerry Kriger: Yeah, I think that’s true. And actually my first field experience in with environmental science was volunteering for researchers in Hawaii studying endangered birds. So I actually started out with birds, but I still just felt the pull to something else and amphibians, even when it hit me, which it did all of a sudden, Hey, I’m going to say.
[00:03:24] Frogs for my PhD research, it just came to me. It just felt like the thing to do, even though people see birds all the time. There’s a lot of wildlife. We do see all the time and that’s probably one reason why birding is so much more popular than frogging or frog watching. Cause people don’t see amphibians much.
[00:03:44] They come with. Generally speaking when it’s rainy, they come out at night and those are times when people go inside. So there are plenty of people if they grew up in a city and always hang out in the city, they don’t even see frogs. So I was fortunate to have frogs all around and even like this time of year, there are toads hopping around all over the place, which is pretty cool.
[00:04:07] So you don’t even have to be near the water, but you have to have some kind of natural areas around.
[00:04:13] Michael Hawk: Exactly. And I had the pleasure of leading a night hike here in the bay area a couple of weeks ago. And that was one of the highlights actually was all of the Sierra tree frogs that were out participating in their chorus overnight. It was a lot of fun to witness that up close, actually see it up close.
[00:04:31] Just a few feet away. And I think that was a highlight for most of the trip goers. So yeah, if anyone’s listening, do a night hike, you’ll be amazed at what you
[00:04:38] Dr. Kerry Kriger: Yeah. Especially if it’s this time of year, which is springtime in the U S. Because in most places in the USA right now, the frogs are definitely at the peak of their activity. So for me, it is the best time of year. And once you start to get to know the frogs that are around you, and hopefully you do have multiple species around you, it’s also cool to follow their phenology, the timing when they become active.
[00:05:04] And see.
[00:05:05] how that repeats itself each year. There are certain species that come out immediately when the ice starts to thaw. And there are some that you won’t hear it all until the first hot day of the year.
[00:05:16] Michael Hawk: Unfortunately where I live, or maybe fortunately we don’t have to worry about ice thawing. But nonetheless, the point well taken and the other fun thing is when you start to see. , from the lifecycle perspective, when the tadpoles start showing up and like with a naturalists, you can actually identify some tadpoles, to the species, which is cool.
[00:05:35] Dr. Kerry Kriger: Yeah, we’re fortunate now to have so much information for. Whether you’re looking for information as a naturalist, just interested in what’s going on out there or conservation, getting ideas on how to save amphibians or whatever wildlife you’re interested in. When I started my career with amphibians, which was 2003, I flew to Australia to do my PhD research.
[00:06:01] There was pretty much no information available online. There was one book by race sandwich called amphibian conservation, and I read that book and that was pretty much all there was that you could get online related to amphibians. And now I built a site save frogs.com. It’s got about a thousand pages and there’s plenty of other websites out there.
[00:06:23] Almost all. Government agencies. If they’re related to wildlife will have something about frogs and whatever region they cover. And then there’s plenty of nonprofit organizations and zoos and museums interested in amphibians, and then just random people who have interest in amphibians. So we’re very lucky and then applications as well, that will help you identify by call or site or upload a photo.
[00:06:48] Michael Hawk: I am intrigued by that. And we’ll look for your recommendations here, maybe a little bit later in the conversation, but I want to circle back to your PhD research. What was it that you were studying and particular?
[00:06:59] Dr. Kerry Kriger: My PhD thesis was on the ecology of chytridiomycosis in Eastern Australia chytridiomycosis is a potentially lethal skin disease caused by a chytrid fungus. So when I started. Batrachochytrium dendrobatidi s was the only known chytrid fungus effecting frogs. And then now these days, we know there’s also a Batrachochytrium salamandrivorans , which tends to harm salamanders the most.
[00:07:30] So I was looking for where I was looking for a kitchen. I wanted to know where it was up and down the east coast of Australia. And specifically I wanted to know. How it changed in prevalence and intensity of infection based on changes in altitude, latitude, breeding, habitat, and season. So which species have at which populations and how can we use that to make predictions about where we would find chytrid and in what populations it would most impact.
[00:08:04] Michael Hawk: At this time, I honestly don’t remember how well known chytrid, fungus and the impact that was having was is this still fairly early?
[00:08:15] Dr. Kerry Kriger: I’d say that was definitely early days. Yeah. It’s never too late to start researching anything, but I thought it was a perfect time for me because. There had not been that many field studies done and the ones that were done, they didn’t really have any systematic manner in which the sampling had taken place.
[00:08:34] It was just haphazard. We took a sample here and a sample here, and it was hard to do much with the data. And then also when I started it’s right, when quantitative PCR was becoming possible. To test for chytrid fungus, meaning that I could test a lot more amphibians in a much less invasive manner And get much more accurate results that actually gave us a lot more data.
[00:08:57] So the data that I was collecting was much different than what people had gotten in the past. So I thought it was a perfect time. Australia was also a perfect place. They’d had population declines and extinctions caused by the chytrid fungus. And there’s a lot of species there. And they also have a very good community, a large community of amphibian biologist.
[00:09:20] So it was a perfect place for it. But yeah, even back in 2008, when I started save the frogs, the primary reason he’s in that I started save the frogs was because virtually nothing at all was being done outside of academia to assist amphibians a little bit in the government. But as far as the public education was pretty much non-existent related to amphibian declines.
[00:09:44] So save the frogs was the first organization to be educating the public uh, an actual focus on students and teachers. And I’m happy to see that these days it’s 14 years later. There’s an amphibian education all over the place. That was definitely not the case back then. So the thing that really got me going to start seeing the frogs was that I was publishing scientific papers and I was reading lots of scientific papers.
[00:10:11] And at the most they would end with a paragraph at the end and the conclusion that we need to do this or that based on the findings in this paper, here’s what needs to be done. And. Yes exactly. But who’s doing that. . One of the goals of save the frogs was, and still is to translate science into action, to take what we know about amphibians and what we’ve learned, and actually turn that into action to.
[00:10:37] Protect amphibian populations and to promote a society that respects and appreciates nature for and wildlife. That’s the mission of save the frogs.
[00:10:46] Michael Hawk: And you’ve been a huge part of that obviously. And the fact that there’s so much frog imagery in pop culture these days I see on people’s water bottles, stickers, related to frogs are amphibians and yeah, there you go. Holding one up. I you’ve been seemingly highly successful in.
[00:11:02] Getting the word out and getting more interest in the space. And I’m wondering when you look back on the 14 year journey that you’ve been on, were there any specific catalyzing points or turning points where you really saw the public taking up the.
[00:11:20] Dr. Kerry Kriger: The first major point of interest for say the frogs was the first annual save the frog’s day, which was April 28th, 2009. And we had 40 events held in 15 countries to raise awareness for amphibians. So people actually going out into their communities and doing something beneficial for amphibians.
[00:11:41] And this was at a time I didn’t have any employees. I hardly had any volunteers. And we were still able to get that much action going. And that’s one reason that I’ve always focused on say the frog’s day as being, the best way to actually get people to take action. And. Yeah, I think, it’s clear people love amphibians, and if you give them ideas on what they can do personally, especially if they already have a little bit of experience in the.
[00:12:11] environment, but there’s plenty of people who take action and it doesn’t.
[00:12:16] Too much to get going. So as long as you can inspire people to take action, give them a reason, show them that there are other people doing this, that it can be done. That it’s fun to do that it’s beneficial. Then people will take out.
[00:12:31] Michael Hawk: That’s great. And save the frog day. I’ll be sure to put it in my calendar for next year. I I saw it awfully late this year and it was in the middle of the. City nature challenge, which I was already
[00:12:43] Dr. Kerry Kriger: Okay maybe they could be combined next year, but you have the 15th annual save. The frogs day will be April 28th, 2023. So I do encourage everybody. Yeah.
[00:12:54] Take part. My goal is to inspire people, to take action and to provide people with educational materials and ideas. So if you go to save the frogs.com/day, then there’s a section there for people organizing an event.
[00:13:10] So if you can organize an event, whether online or in-person, that’s great. Otherwise just spread the word. We’ll be putting out lots of save the frogs date imagery. So go ahead and share that.
[00:13:21] Michael Hawk: I already see a city nature challenge, frogging outing. For next year that I’ll see if I can arrange one. Yeah. So why don’t we back up a little bit and just establish some natural history context for frogs and one thing that surprised me and I feel slightly embarrassed to say this, but I was looking at your website and I saw in one of the FAQ pages that toads are essentially a sub classification of.
[00:13:48] And I always assume that they were like parallel splits in the genetic trees. So, Tell us a bit about what makes it frog and what their life cycle is.
[00:13:59] Dr. Kerry Kriger: Okay let’s take a step back and just talk about amphibians first. There’s really three groups. Of amphibians. There’s the frogs and toads, because as you just said, tones are a type of frog. The toads are a family of frogs, so there’s the frogs and. And then there’s the salamanders and newts, newts are just a type of salamander.
[00:14:22] All right. Then the main difference between those is going to be the tail that the salamander, the new south, and then there’s the least known amphibians, which are the Caecilians, which are the limbless amphibians and they don’t call. They don’t congregate. They’re fossorial so they tend to be underground.
[00:14:40] They’ll come up when there’s heavy rains so most, and they don’t live in the United States. They’re in tropical areas. So most people will never see them. I’ve never seen one and I’ve spent a lot of time out wandering around the tropics. So consider yourself lucky if you see a wild Caecilia and those are the three main groups.
[00:14:59] The difference between the frogs and the toads. I’ve heard so many different things stated as the difference, but really anything that is.
[00:15:07] often stated as a difference could apply to the other group as well. So we’ll hear things like toads have toxins. True. All toads have toxins on their skin. Some frogs also have toxins on their skins toads have short legs.
[00:15:22] Usually true, but some frogs do two toads, tend to walk and not hot, but the other night, I saw plenty of toads hopping around. So it’s just, they’re easily identified visually and that they tend to have what people describe as worty skin. Lots of bumps on their skins are not actually worts. So the toads though are definitely a type of.
[00:15:45] Michael Hawk: of the. Nuance. And it’s just a human construct to say speciation, or, develop a taxonomy, but using that framework about how many species are there, frogs and toads.
[00:15:56] Dr. Kerry Kriger: There’s almost 8,500 known amphibian species of which about 7,500 are the frogs and toads.
[00:16:04] of the remaining 1000 amphibian species, about 800 are salamanders and newts and 200 Caecilians. So the vast majority are frogs and toads. Interestingly, though, in the USA, we’ve got about 326 known amphibian species.
[00:16:22] Of which 210 species are salamanders in Knutson. 116 are frogs and toads. So in the U S we’ve got more salamanders and newts and actually the Appalachian mountains specifically in North Carolina, that’s the hotspot, the biodiversity hotspot of the world for salamander.
[00:16:41] Michael Hawk: I have a field guide to California. Reptiles and amphibians. And I remember there’s a whole bunch of slender salamanders in California that are located in very restricted ranges. And to me, that makes me think that, oh, there’s inherently a vulnerability in those populations if they have a small range to begin with.
[00:17:00] So what is the current generalized state of the world, maybe start in the United States of amphibian. Oh the words escaping me threats. Yeah. That’s a good way to say it.
[00:17:09] Dr. Kerry Kriger: Amphibians. One of the reasons that I wanted to work with amphibians because my overall goal was to save the planet. So how are we going to save the planet, save wildlife, which wildlife, the most threatened wildlife, at least the most threatened vertebrates are the amphibians. So it’s about one third of amphibian species are considered threatened with extinction means that if we don’t do any.
[00:17:31] To remove the threats they face or lessen them, then we can expect them to go completely extinct in the near future. So amphibians as a group are more threatened than the reptiles or fish or the birds or mammal species. Another. Is that about last I heard about 48% of amphibian species were on the decline in numbers and only two to 3%.
[00:17:57] We’re increasing so many thousands of amphibian species are threatened with extinction. And what you were talking about before with geographical distribution, these amphibian species that have small distributions, they do tend to be more threatened with extinction and. Those with smaller populations are harder to study.
[00:18:19] There’s less chance that there are people studying them. And so we also, there’s about 1500 amphibian species that are considered data deficient and many of those data deficient species. We don’t know what’s going on because their population sizes are so small that they’re hard to study. And therefore we assume that many of those species are also threatened.
[00:18:40] So the true number of threatened amphibian species is likely far higher than one third. Now in the USA, I don’t have the precise number. I don’t think it’s the third. It’s a little bit less, but there are plenty of endangered amphibian species in the country. Fortunately in the U S. We do have a lot of laws in place.
[00:18:59] We have an endangered species act. Some countries don’t have that. We’ve got a clean water act. We’ve got departments at all levels of government who are tasked with keeping species alive. So that’s a good thing.
[00:19:13] Michael Hawk: Absolutely. And there’s so many directions I can go with this since we’re talking about the threats to amphibians. One thing that I’ve. Looking at much more closely here in recent months is connectivity for wildlife and dispersal habits. And talking about range restrictiveness of some of these species.
[00:19:33] My assumption, and you can correct me here. My assumption is that, that frogs and toads and salamanders are pretty restricted in their own. Like If you just take an individual , the range that it will travel is fairly restricted. Is that accurate? Or can you characterize. Dispersal looks like.
[00:19:50] Dr. Kerry Kriger: Generally speaking, I’d say that’s correct. There are some. Which tend to be the large species I’ve got big legs. They can jump, they can go a long way. Some famously can migrate far such as cane toads in Australia, which are not native, but they’ve actually evolved. So that those on the frontline of the invasion or hopping faster than the other ones.
[00:20:11] But generally speaking. Yeah. And amphibians, they tend to be pretty small and they can’t get too far. And there are also, many of those species are just not genetically predetermined to be moving all around. So they’ll go when they’re juveniles is when they tend to migrate and. They need good habitat to move through, to get wherever they’re going, which is probably hopping along until they find another suitable water body.
[00:20:40] So one big difference between birds and amphibians is that if something happens to the birds habitat, most birds could fly off in search of new habitat. And that would be, you know, a normal. Easy thing to do, assuming that there’s other habitat to go to, but for amphibians, if something happens to where they expect to be, then they’re just not going to naturally be able to find a new place with ease.
[00:21:06] So that is one reason that they are considered bio indicators.
[00:21:10] Michael Hawk: So many things could happen. I’m thinking about the drought in the west that’s happening and traditional. These could be disappearing. People removing beavers, changes a habitat dramatically, lots of different things. Let’s go back again and let’s talk about the life cycle a little bit.
[00:21:27] And I realized that every species is going to have a slightly different life cycle timed with the local habitat and the seasonality and so forth. But can you tell me again, focusing on frogs what a typical. Maybe you could pick an example, a well-known species, you know what that looks.
[00:21:42] Dr. Kerry Kriger: Yeah I’ll just say there’s going to be two, two primary groups of. Ox and toads, there’s going to be direct developers, which will emerge straight from the. As a froglet, they’re not going to go into the water as a tadpole. And then there’s the ones that we tend to think of as frogs and toads is to have a tadpole stage. So as an, if they do have a tadpole, they’ll have gills they’ll have a tail they’ll be probably, usually are herbivorous eating algae and leaflet. in the water, but they could be carnivorous. They do have teeth. That’s one of the best ways to identify tadpoles. They have potentially multiple rows of teeth.
[00:22:25] And that will change by species, regardless. So as they grow, the tail is going to go back into their body. They use that for energy. It doesn’t drop off. They pop out their hind limbs and then their front, their arms will say, and then the. Gills will change into lungs and they’ll emerge from the water as a metamorph.
[00:22:46] They’ll probably still have a little bit of a tail. And then maybe a few weeks later, they’re a juvenile frog there in the form of a frog. And then probably after one year there’ll be adults and can reproduce. They’ll have external fertilization in all of this. All species. So that’s the standard frog lifecycle that we think of, but there are a good number of species who are direct developers and they depend on moist leaf litter.
[00:23:13] So as you were saying, there could be droughts or in cloud forests in the tropics when the earth heats up, the cloud levels tend to rise. And it’s the clouds that are keeping the leaf litter moist. So when that happens, The frogs could potentially move up the mountain or maybe just the populations up high would survive regardless.
[00:23:34] There’ll be fine. But if you go up a mountain, you eventually run out of space. Those species that are under significant threat, direct developers who are up in the mountains in places where it’s dry.
[00:23:45] Michael Hawk: So in the first group that is, has a tadpole stage. If they’re in a body of water as a tadpole. And let’s say that body of water is shrinking, the temperature is warming up. Can they speed up their development based on the environmental characteristics or is it just a death sentence?
[00:24:04] Dr. Kerry Kriger: I wouldn’t say it’s a death sentence, the parents did their best to predict how much Wayne. So I’m in Virginia right now, the gray tree frogs last night, it was rainy. It was also cool, but they weren’t calling at all. That’s because three weeks ago it was also rainy and they knew that they’d have the highest chance of their offspring surviving by laying their eggs.
[00:24:29] Then, whereas now it’s, there’s really hot days now, so they do their best to know. Now’s the time to mate have the eggs where they have the longest chance of being in water and hope for the best. But yeah, if they, if the pond is drying up or the pool that they’re in is drying up the puddle, then they will speed up.
[00:24:51] From what I know about most species, I don’t know if that’s been tested and how many species, but generally speaking, it’s assume that they will speed up. But that doesn’t mean they’re going to get out on time. That’s why some people write me and they say, Hey, there’s all these tadpoles in a post.
[00:25:06] What should I do? And I say, watch them daily if possible, don’t move them unless you, unless it’s like VN, because they will die. If it dries up, if you do move them, the ideal place would be to move them to the closest water body where you think they could survive. If there’s still water in there, then let them be.
[00:25:28] And hopefully they will get out on time. Now they’ll also change their dietary habits. They could become cannibalistic cause they need the energy to metamorphose. And if, they’re not getting that from the leaf litter and there’s other tadpoles, even of the same species or even of the same family then they can start eating them depending on the species.
[00:25:49] Michael Hawk: Interesting. Yeah. The desperation kicks in and crazy things start. Yeah.
[00:25:53] Dr. Kerry Kriger: it takes to get out of.
[00:25:54] Michael Hawk: Yeah. And I think for some species , based on the scenario that you just mentioned, it seems to me that ephemeral pools, Vernal pools are probably important because they are disconnected from maybe where other predators might be. And it’s also a risk then, that these pools could dry up too fast.
[00:26:13] So what is the situation in terms of predation on. Frogs during say either as eggs or as.
[00:26:22] Dr. Kerry Kriger: I think throughout their entire life there’s risk of predation and species are definitely split up according to. Their preferences for their tadpoles. In how long their tadpoles live American bullfrogs may remain as.
[00:26:38] tadpoles for years and therefore they need permanent water.
[00:26:43] So if you want a pond with frogs and you don’t want bull frogs in there, cause bullfrogs are very large and like to eat other frogs, then one of the best things you can do is ensure that the pond dries up each year. How are you going to do that? You’re going to make it shine.
[00:26:58] Michael Hawk: Sorry, just to jump in and here in California, I’m not sure how much of the west, the bullfrogs aren’t native and they’ve they’ve really made inroads. And I think that’s also a challenge for some of the native. So even though it’s called an American bullfrog, it’s not necessarily, you don’t necessarily want it.
[00:27:14] Dr. Kerry Kriger: That’s correct. And I’m happy to talk about American bullfrogs and what I have been doing, what say the frogs has been doing to reduce the spread and importation of non-native bullfrogs. Bye. Let me first just finish up this kind of natural history discussion where I’m living. There’s two ponds. Yeah, One is deep and is permanent.
[00:27:35] And one is only, it gets maybe four or five inches deep when there’s a lot of rain and that pond. Has generally speaking completely different species. The two ponds are only a few hundred meters apart, a few hundred yards apart. Okay. So one of them it’ll get gray tree frogs and spring peepers, and a lot of toads hanging out in the pond.
[00:27:58] It was going crazy with frogs a few weeks ago when it was still cool, but very rainy and the deep pond didn’t have any vocal activity, any calling until about four or five days ago, it got really hot. And now there’s Northern cricket frogs down there. There’s green frogs there’s bull frogs.
[00:28:16] So definitely the depth of water has the hydro periods specifically. How long has their water in the pond has a huge impact on what species you’re going to find?
[00:28:26] Michael Hawk: Yeah, that makes sense. Every subtle difference in the habitat seems to have some species that’s adapted to that difference.
[00:28:33] Dr. Kerry Kriger: Correct.
[00:28:34] Michael Hawk: I mentioned the bullfrog. Why don’t we tell me a bit about what you’re doing with the bull.
[00:28:38] Dr. Kerry Kriger: So the bullfrogs are the largest frog in the largest native frog in north America and they are. Native to the Eastern half of the USA and Canada. So generally speaking, east of the Mississippi river, there are large frog. Frogs are called gape limited predators. They’ll eat whatever they can put in their mouth.
[00:28:58] They’re carnivores as adults. If it’s alive and they can fit it in their mouth, they’re going to eat it. The bullfrogs have a very large mouth. Now the bullfrogs also happen to be well, they’ve got big legs and some people like to eat frogs legs. When the California gold miners ate most of the California red legged frogs and drove them to near extinction.
[00:29:19] And that species is the largest frog native to the Western us. Then there came a financial opportunity to import American bull frogs, farm them and sell them. And that’s the origin of why there are non native American bullfrogs in California and up and down the west coast now. Starting say 10, 20, 30 years ago.
[00:29:43] It also became very popular to farm American bull frogs around the world as the primary source of frogs in agriculture. So now you’ve got American bullfrogs in at least 15 countries around the world where they don’t belong. They escape. And they do a really good job of establishing populations. They’re going to eat native frogs in those areas.
[00:30:08] And then many of them are getting shipped to the United States, not in very sanitary conditions. There’s going to be first off. I’ve got a video of frogs somewhere in Asia and some agriculture. Business setting it’s I won’t call them ponds. They’re manmade structures with water then are probably hundreds of thousands of bullfrogs visible in the video.
[00:30:34] They’re just covering every inch of water. They’re all over each other. And we know what happens when you put a sick organism in close quarters with other ones they’re going to spread their disease. Chytridial mycosis is a skin disease. So then they get shipped to the United States and I see them in buckets, a bucket, a standard sized bucket with water in it.
[00:30:57] And 25 or 30 bullfrogs in there just crawling all over each other. And from the studies that have been done, they found that 62% of the frogs coming in were infected with kindred fungus. Now, I think these days it’s probably even a lot higher. So about whatever it is. There’s a least a couple million bullfrogs being imported into California each year.
[00:31:22] Legally the department of fish and wildlife gives out permits for the importation. And so that means there’s at least a million chytrid infected frogs coming into California each year. Chytridial mycosis. If I didn’t say it before, is the worst disease. In recorded history in terms of biodiversity, it’s driven about a hundred amphibian species to complete extinction.
[00:31:45] There’s no other disease we know of that has caused so much problems for wildlife. So we’ve got this horrible disease coming in. Why’s it coming in because people like to eat frogs and some people make money off of the importation and sale of it, and they have done a good job of preventing any type of legislative change from happening in California.
[00:32:09] So since 2010, I’ve been speaking with politicians. Speaking at governmental hearings, I’m involved in a I’m part of a stakeholder group currently that the department and fish, or the California fish and game commission is running which hope, which has been going on for literally three and a half years or so.
[00:32:30] It was my hope that it would not take more than six months. This is the way that they collect information at, government speed we’ll call it. So we’re three and a half years in. Hopefully it will actually result in some change. And if it does not, the bullfrogs they’ll keep coming in. They’ll keep getting set free or escape the water that they’re held in.
[00:32:51] We’ll Get into the environment and spread disease and we’ll continue to have significant problems with bullfrog. So for me, one of the easiest ways that California could improve. It’s natural history and state of wildlife is simply to stop allowing the bullfrogs to come.
[00:33:07] Michael Hawk: Chytridial mycosis how does it spread? Is it through water or close contact or I’m wondering if this, if they were able to stop the influx, then what does the future look like in terms of controlling that, which has already.
[00:33:22] Dr. Kerry Kriger: Yeah, the chytrid, fungus is definitely in a lot of places. And some people say, oh, because it’s in so many places, we shouldn’t even worry about it anymore, but there’s different strains and different pathogenicity of the Kendrick fungus. When it’s in a population, eventually the frogs do gain some kind of resistance to it.
[00:33:41] It takes a long time, unfortunately, but that’s even more reason to ensure or do our best to prevent new strains from coming in. So Yeah, it’ll spread the kitchen that has Zoe it’s got waterborne zone with sport. And it’s on their skin. If they’re in the water, then the kitchen’s is going to get into the water.
[00:34:03] So if you have a bucket of chytrid filled water with millions, or probably even billions of those spores and you let it out into the wild kit, or it does a really good job of surviving in a lot of different climates, it’s going to do. Most damage to amphibians in cool, moist climates halfway up the Sierra Nevadas.
[00:34:23] Okay. Not where it’s completely snowy all the time, but just where it’s cool. It’s like the best temperature for a kid who has probably about 13 degrees Celsius. So maybe 55 degrees Fahrenheit or 60 degrees or so, and yeah, it’s going to move around. If we’re importing millions of frogs in, but ideally, ideal situation is where the kids are at is okay.
[00:34:46] It’s hard to eradicate the kitchen from a wild location, but at least let the amphibians there adapt to it and don’t give them any new strains of it to have to do.
[00:34:55] Michael Hawk: Yeah, it sounds like there’s some parallels that that we humans could take from that approach with respect, say to COVID or some other things that are going
[00:35:03] Dr. Kerry Kriger: Yeah. It’s you know, before with COVID, people can understand a lot more when you talk to them about amphibian disease, it all makes sense. Cause we’ve seen it happen, happens the same way. If If we have sick humans and they’re traveling all around the place and the thing is. With humans, at least they put in controls, like add, get a task before you enter the country, go into quarantine.
[00:35:23] But for amphibians, aside from Australia and New Zealand, which have had significant problems with invasive species of all kinds. So they instituted controlled. Long ago to reduce the influx of amphibians into their countries, but pretty much everywhere else. It’s easy to get a frog into a country and there’s not going to be disease tests or quarantines the vast majority of the time.
[00:35:50] Michael Hawk: You have me convinced that this is a worthwhile thing for the state to do. And I’m guessing it’s probably not just California or is California really the only big importer of these.
[00:36:00] Dr. Kerry Kriger: It’s definitely not the only, I think of New York city as being another hot spot for importation San Francisco, LA New York city. A lot of the frogs are coming in for Asian cuisine. So wherever there are big Asian populations, I’m sure that they’re coming in or I’m not sure I need to look into it, but I’d say Vancouver, Seattle probably have a lot, but I know that there are states in the west.
[00:36:25] I can’t remember if it was Oregon or Washington that I was just hearing about that do have at least some. Higher level regulations than California, which is in California. It’s pretty much apply for a permit, pay a very small amount of money, like $40 or so get your permit in port frogs. And then the next time you need a permit, you do it again.
[00:36:47] It used to be, you’d get one permit. They’d call it a longterm permit. Meaning you’re good to go. And then they thought the big change was to make it short term, which is just apply again, but he could put people, still get them. No problem. So even things like one crazy thing in California, right on the permit form, it’s got a big, bold statement about needing to have disease testing done.
[00:37:08] But it’s not being enforced. And I wrote them about them. Like it’s written right here, but you’re not doing that. So there’s unfortunate stuff that happens at the governmental level that could easily be changed from my perspective.
[00:37:20] Michael Hawk: Yeah, I see that. And one thing I wanted to ask you about is. Anyone who wants to do something to help save the frogs or their local amphibian population, what can they do? How could they help you? How can they volunteer with your organization?
[00:37:36] Dr. Kerry Kriger: Okay. Yeah. One thing that we didn’t discuss that I’ll just throw out there real fast. Cause I know a lot of your listeners probably have a general idea about threats to any type of organism out there, but let’s just, if we want to save frogs, we have to know what the problems they’re facing. We talked about disease, but habitat destruction is the number one problem around the world.
[00:37:56] And that means that. Protecting habitat that still exists, restoring habitat that is degraded and even potentially constructing new habitats. Those are some of the best things that we can do. Cause habitat destruction is the number one problem for amphibians around the world. So if you’re a home. Or a land manager or somebody who has access to land and the ability to make decisions, or if you know how to get those people, to make the decision, to build a frog pond, then that’s one of the best things that you can do for our bonds, especially out in California.
[00:38:31] They don’t have to be very big. The Pacific chorus frogs will use a frog pond. That’s just, a few feet across. So you don’t even need a lot of space, but if you can build something larger than we encourage you to do that, we have saved the frogs at academy. Save the frogs.com/academy. Anyone can get 28.
[00:38:50] Full free access to all the courses and save frogs academy. And we just published one called how to build a backyard wetland. And it walks you through in about 40 minutes, total of videos, what to do to build a low cost, naturally appearing and naturally functioning wetland. What’s that mean? It’s not going to look like those ugly Ponzi C built by construction people, beside a parking lot that, it’s just, it doesn’t look like it’s natural. Yours is actually going to. Be nice looking at may even improve your property value because people like having nice looking land and it’s going to function naturally. That means you’re not going to build a dam. That’s going to need to be, it’s not going to need maintenance when we build ponds, they’re ideally there for decades or possibly even centuries.
[00:39:39] So build a frog pond. Next thing there’s pollution and pesticides. If you can avoid the use of pesticides on your property, then. Definitely try to do that. If you can buy organic food, then do that global warming. We talked about briefly. So there’s not that much we can do aside for improving our own ecological footprint, lobbying for change, choosing companies that have put, try to do good things for the.
[00:40:08] Michael Hawk: My audience consists of a lot of nature seekers and naturalists, and, we encounter frogs toads and other amphibians at various times. So when we’re out, when we’re hiking, when we’re seeing nature, what can we do to say lessen the impact that we have on amphibian?
[00:40:29] Dr. Kerry Kriger: Amphibians tend to live in habitats that humans don’t really spend too much time in. So if you encounter them out in the wild, I think the best thing to do is take a photo or two. Don’t harm them with your light. If you’re out there at night, you can take a flash photo. That’s fine, but don’t take lots of them.
[00:40:47] You can see if the amphibians starts to get stressed out, it’ll crunch up and close its eyes. And the other thing is. Some photographers like to handle amphibians a lot, to get the perfect shot. I just prefer take the best photo that I can in the, let it be. And then it’s in its most natural position.
[00:41:04] Aside from that, I don’t think there’s too much that we need to do. Most people are probably not going from habitat to habitat or visiting endangered from. If they were, there could be some disease precautions to take, but generally speaking, just let the amphibians be. When you see them, enjoy their presence, take an audio recording, take a video, take a photo, and then move on.
[00:41:29] And if you’re a naturalist and you do know a lot about frogs, Hopefully take some people out there who don’t know too much about frogs, introduce some new people. And there may be people like, Hey, they’re into birds. They probably would be into frogs. They just don’t think about them too much. So if you can get some of those high likelihood people to enjoy frogs, and that would be.
[00:41:50] Michael Hawk: Sounds good. And yeah, it’s always good. You spread the joy of of native wonders like that. And vocalizations, I, you mentioned something about vocalizations earlier and I wanted to follow up on that real quick. So I think many people are used to hearing a single type of vocalization. Are frogs communicating beyond just saying, Hey, I’m here.
[00:42:11] Dr. Kerry Kriger: Yeah it’s called their advertisement call. It can serve different purposes. Generally speaking, only males are calling a female could call if it’s an emergency call, but generally just the male. So that’s one way to know if it’s a male or a female and it’s going to be. To attract a mate to say, Hey, I’m here, come over here.
[00:42:33] Or to defendant’s territory to say, Hey, I’m here.
[00:42:35] go away, depending on who it’s calling for. Or it’s probably serving both at the same time. And every species has its own unique call. That’s one of the ways that scientists can identify. Identify the frogs is by their calls. So it was one of the best ways that we, as naturalists can get to know what frogs are out there into, to conduct surveys.
[00:43:00] It’s pretty much critical when I was studying frogs in Australia. For my PhD research. One of the first things that I did was I got a CD of the calls of frogs, of Eastern Australia. And I’d listened to it all the time. If I was, if I were driving to a study site, I’d have that in there just to get to know all the frogs so that when I’m out there, I would hear them and know right away.
[00:43:22] What is calling and because I would need to call to them in order to catch them, I’d catch them in a plastic bag and run a cotton swab over their skin to collect a sample of a potentially kindred fungus. And I’d let the frog go. And for me to actually catch a frog, I’d have to really know where it was.
[00:43:40] And frogs tend to be pretty shy. Most of them. Get quiet when you get close. So one way, if you really need to know where it is then is to call like a frog and it’ll think that you’re a male frog and we’ll call that.
[00:43:52] Michael Hawk: Interesting. Are there any resources you’d recommend for people that I like? I’m thinking about all these great apps that exist these days, like Merlin for bird vocalizations. Is there anything like that for frogs?
[00:44:04] Dr. Kerry Kriger: There’s none that I use, usually if, I need it to know what was in location. Get on the web, find a website related, you know, just type in frogs and toads of geographical region. And, but there are some geographic specific apps, but I don’t know of an app that’s applicable, worldwide, but there’s the best thing is always just search for frogs and toads of your part of the world.
[00:44:28] And you should definitely find some.
[00:44:30] Michael Hawk: All right. So I’d love to hear more about your organization and what people can do, what my listeners can do to help you and more generally help amphibians. So can you tell me a little bit about, a little bit more about save the frogs? You mentioned already some great resources and perhaps some projects or events or things like that, that they can join in on.
[00:44:48] Dr. Kerry Kriger: Sure. The first thing everyone should do is go to save the frogs.com, which I’ve put many hundreds, probably thousands of. Into building. It’s got tons of information, probably everything that we’ve discussed in a lot more depth. The best thing always education to me is the root of all successful amphibian conservation.
[00:45:07] And that includes educating yourself about amphibians. So go there and you’ll get plenty of ideas. To start out with, as I mentioned before, we have saved the frogs academy and right at the top of the site of the menu, you can go get 28 days free of say the frogs academy, full access, and then get involved in some of the uh, projects and offerings that we have.
[00:45:28] We have, as we already talked about, say the frogs day, that’ll be coming up April 28th, 2023. We also have a save the frogs art contest. So if you’re an artist or if you’re a teacher, then that’s definitely one of the best things that, you can do. Our art contest. We’ve had probably about 20,000 entries from about a hundred countries over the years, and it’s definitely one of the best ways that teachers can get their students.
[00:45:53] Interested in amphibians and educated about amphibians because teachers don’t even need to note too much about amphibians. they can send their kids to our page, save the frogs.com/art and the kids get inspired and get ideas. And we can see from the art that comes in, that the kids learned a lot about the threats to amphibians and why they’re in trouble.
[00:46:13] Why they’re important. We also are reviving our safe frogs poetry contest, which we ran for many years. And so if you’re a poet and want to express yourself that way, we actually have a say the frogs poetry book, you can download it on our site, inside the frogs academy and our save, the frogs photo contest is coming back this year as well.
[00:46:34] So if you have incredible amphibian photos or even pretty good amphibian photos, we encourage you to submit them. Other things, if you want to get outside, then I’m not sure when this podcast is going to air, but regardless of when it comes out, we have eco tours and thus far, they’ve all been in Latin America.
[00:46:55] We’ve done eco tours and Belize Costa Rica, Ecuador and Peru June and July of 2022. We’re going to be in Costa Rica. If you want to join a tour, let us know. And even if you’re listening to this after that, then we’ll almost certainly have some kind of tour scheduled, which you can learn about save the frogs.com/eco tours.
[00:47:16] Most of the tours are between eight and 12 days. We go out to really beautiful places. Stay in nice eco lodge. And we always see a ton of frogs and learn a whole lot. And that’s definitely what I’d suggest to anybody who is really interested in amphibians. The other thing that we have going on.
[00:47:36] is each year we’ll have at least one wetland construction workshop.
[00:47:42] So we don’t have it planned at the moment. The recent ones have been in California. We’re preparing to we’re raising money. Currently. We’ve already designed wetlands for California red legged frogs in Northwestern, Mexico, and we are aiming for 2023 to build those wetlands. So we have a page save the frogs.com/wetland.
[00:48:02] And if you’re interested in learning how to build a wetland, or even if you don’t want to build one for yourself, but just want to get outside, meet some other frog savers and do something good for the environment. We always need volunteers for those projects. Aside from that, say, you don’t want to leave your house.
[00:48:19] We have volunteer positions. We have a page. Say the frogs.com/volunteer. With a lot of ideas on how people can help. And we’re always adding new volunteer positions to that page. And even if you don’t see something, that’s precisely what you think you can do. If you have some type of professional experience and actual dedication to helping out then contact us and we’ll definitely find something away for you.
[00:48:46] Michael Hawk: Tons of great options. And, you’re also pretty active on social media. Where can people find.
[00:48:52] Dr. Kerry Kriger: @savethefrogs we’re on Pinterest, Twitter, Instagram, Facebook, just type in savethefrogs and you’ll find.
[00:48:58] us. And we also have a community in discord. That’s the best way to actually interact with other, say the frogs people. So for that, you can go to savethefrogs.com/discord.
[00:49:09] Michael Hawk: Perfect. You’re in all the places.
[00:49:11] Dr. Kerry Kriger: Wherever you want to be.
[00:49:12] What we’re probably gonna be.
[00:49:13] Michael Hawk: I’ll make sure I’m following you in all those places as well. I think I’m on most of them anyway. Maybe I still need to join the discord.
[00:49:18] So I asked my Patreon patrons, if they had any questions that would be relevant to this interview. And I had one Barry, he sent me this, he says, we now have a seasonal Creek on our property and I’m. If there is anything we can do to make the habitat more friendly to frogs and toads, perhaps things like weed, pulling, removing dead branches, adding native water, loving plants I’m not exactly sure.
[00:49:41] We hear frogs calling in the valley, so I know they’re out there, but we haven’t seen any on the property yet. And he is in California.
[00:49:47] Dr. Kerry Kriger: I think the best thing to do is not to do anything at all. Aside from maybe keeping domesticated animals out of there. You don’t want cats down there eating frogs, but as far as. Is it good habitat? Yes. Cause you know, there’s frogs down there. The frog’s already like it don’t remove branches. Frogs tend to like places that, humans think of these days is ugly, and that means that it’s got a lot of shrubs and stuff growing. It’s got fallen trees. That’s all good for habitat. I don’t think you need to do anything. Just enjoy the property and the frog frogs come there and do their thing.
[00:50:25] Michael Hawk: Thank you for the question. Barry.
[00:50:27] Let’s uh, transition to a few wrap-up questions. First of all, for people who are interested in amphibians, or maybe just nature in general, do you have any recommended reading documentaries, things like that, that you’ve found to be inspirational, valuable useful.
[00:50:43] Dr. Kerry Kriger: For amphibians, there’s a documentary called a thin green line. I think you can watch it for free on the PBS website. So go check that out a thin green line. And as far as books, I don’t necessarily have any favorite amphibian books, but some of my, some of the books that inspired me to go into a career.
[00:51:03] Related to protecting the environment cosmos by Carl Sagan, desert solitaire by Edward Abbey and Charles Darwin on the origin of species, which I think is one of the best books on natural history ever written. Even if you’d take a side, take out all the stuff about evolution and just read his natural history thoughts.
[00:51:25] I really liked.
[00:51:26] Michael Hawk: Wow. You really picked some classics there, so highly recommend those ones. , based on all of your experience, Magically impart one ecological concept to help the public, see the world as you see it, what would that.
[00:51:39] Dr. Kerry Kriger: It would be that saving the environment is both fun and healthy. I think people always feel better after putting in a day saving the frogs. And I think people realize a lot of people have, we’ll call it environmental pessimism. Maybe they’re pessimistic in general, the world’s coming to an end.
[00:51:58] The environment is, insert your bad word there. But I don’t think that’s the case. I think people can do a lot for the environment. And if. Thousands hundreds of thousands, millions of people doing good things for the environment, then it definitely has a visible effect. And we’ve seen tons of great things happen for the environment.
[00:52:18] And that’s what keeps me going year after year is that the more we do the better, the chance for the frogs and other wildlife and the higher, the chance that we have a planet that.
[00:52:30] we enjoy living on.
[00:52:31] Michael Hawk: Here Here. It reminds me of the quote, the best time to plan. I was 20 years ago. The second best time is today and ended, applies, I think for the environment as well. All right, Dr. Kriger, is there anything else that you wanted to say? Any topics we missed or whatever it might be?
[00:52:47] Dr. Kerry Kriger: I think we covered a lot. I think everyone should just go outside when he can go outside of. In a place where you think there’s going to be?
[00:52:54] frogs, go looking for frogs, take a headlight out there, stay safe. When you’re out there, check out, say the frogs.com stay in touch. If you want to contact me, go to the contact page on say the frogs.com send an email or find us on social media.
[00:53:09] Michael Hawk: And thank you so much for making all of this time today and for the thoughtful and insightful answers to the questions it’s been very enjoyable.
[00:53:17] Dr. Kerry Kriger: Thanks, Michael, for having me on and for spreading the word about all the environmental scientists and environmental organizations that you.