Jul 23, 2020
Head north of Sacramento along any of the major freeways, you’ve likely seen the lush green rice fields with ubiquitous wildlife such as herons, hawks, and egrets. What may surprise you is just how diverse the rice field ecosystem is – and the unseen giants at home in those fields.
Nearly 230 wildlife species depend on Sacramento Valley rice fields for food and a resting place, including the giant gartersnake, a threatened species.
Although it has “giant” in its name, this creature is, at most, five-feet long. These snakes are heavily dependent on rice fields for their survival; having lost most of their earlier habitat – traditional wetlands, which have been lost over the generations.
Anna Jordan and Allie Essert of the U.S. Geological Survey are among those working to maintain and enhance the giant garter snake population. They work in rice fields, trapping and tracking the snakes. The more they understand about this species, the better chance it has at surviving. This is unusual work may not appeal to many, but these biologists love what they do.
“It’s really kind of funny. Whenever I tell people what my job is, the first question I get is ‘Why?’” Anna said. “It’s a hard question to answer. You don’t get that question when you’re an accountant or a doctor. I love what I do and I wouldn’t change it for the world.”
Those who don’t like snakes – and there are many in that category – may not realize how valuable they are.
“For all of the people who don’t like snakes, you probably don’t like pest species either,” Allie remarked. “Snakes do a lot to keep pest populations down. They help to regulate the ecosystem as an aquatic predator.”
Here are links to more information on this rice field giant:
- USGS Article - Construction and analysis of a giant gartersnake population projection model
- Article - Conservation reliance of a threatened snake on rice agriculture
- Article - Behavioral response of giant gartersnakes to the relative availability of aquatic habitat on the landscape
- WERC Scientists Find that Threatened Snakes Depend on Agriculture
Episode Transcript
Anna Jordan: It's really kind of funny. Whenever I tell people what my job is, the first question I get is, why? It's kind of a hard question to answer, because you don't get that question when you're an accountant or a doctor. So, it's definitely really interesting and I love what I do and I wouldn't change it for the world.
Jim Morris: Anna Jordan and her coworker, Allie Essert have really unusual jobs and I mean really unusual. But, what they and other colleagues are doing here in the rice fields of the Sacramento Valley, should pay big dividends for our ecosystem. Welcome to Ingrained, the California Rice Podcast. I'm your host, Jim Morris. Proud to have worked with California farmers and ranchers for 30 years. And today, I'm in the Natomas area at a rice farm, about a 15-minute drive from the state capitol. Sacramento Valley rice fields are home to nearly 230 wildlife species. And that includes millions of ducks and geese, more than a dozen types of raptors, and world-class habitat for shorebirds.
Jim Morris: In my travels, I've seen bald eagle parents teaching their young how to hunt in a rice field. I watched an epic grind of about 30,000 snow geese in one shallow flooded rice field in the winter. I had to stop while a river otter family crossed the road in Yolo County, that was awesome. And only yesterday in Colusa County, I watched a muskrat peek its head up from a small canal next to a rice field. One of the most unusual species we have is also heavily dependent on rice fields for its survival. It's the giant gartersnake. I'm speaking with Anna Jordan with the US Geological Survey. And can I ask what your title is and how long you've been working with giant garter snakes?
Anna Jordan: I am a wildlife biologist with the USGS and I'm also one of the project managers on our giant gartersnake project. And I've been working at the US Geological Survey since 2014. Basically right after I graduated college, I started and never stopped. And I loved it enough to start managing the project.
Jim Morris: How important is it to maintain this habitat? We have a lot of urbanization in this area. It's critical for the snakes, right?
Anna Jordan: So, the giant gartersnakes are a federally and state listed species. They are threatened. And the major reason for that is because of habitat loss. There used to be historically a lot of native wetlands, but like you said, with urbanization, a lot of those wetlands have been completely replaced by agriculture. And in some places that agriculture is orchards or sunflower fields, very dry crops, but giant gartersnakes are a wetland obligate species, which means they need water to survive. And, in the Sacramento Valley, which a lot of people may not know, we grow so much rice and this rice basically acts like a wetland for snakes, and it's what allows their population to exist at all. And so it's so important for them.
Jim Morris: So we're right along Highway 99, checking out traps and Anna, how many do you look at in a given time that you're out here?
Anna Jordan: So, our trap lines are made up of usually about 50 traps, but we can go upwards to a hundred, depending on how big the canal is because we want to get a good even sampling of the length of the canal. This one is only 50 and they're are about 10 to 20 meters apart. And that really just makes it so that, if we have a snake, we know that we're sampling the entire canal and where they could possibly be to get an idea of what the population is like there.
Jim Morris: Oh great. You have a very large pole and you're going to see what we have here. So why don't you go forward and do that please? And this is a trap that's what, about three feet long, I guess? What do you have in there?
Anna Jordan: Look at that. Lucky snake number one in trap number one. And there's also a crayfish with him, which is pretty common. There's a lot of crayfish and these rice fields, so that's a pretty common trap content. And here we go, this looks like an adult snake. I think it is a male, which you can tell by the length of their tail, but we do also probe them to check for the hemipene pockets.
Jim Morris: This one looks pretty lively and healthy to me, but you're the expert. So tell me about the overall health here.
Anna Jordan: Yeah, I would say the snake seems pretty healthy, rambunctious, lively, not super happy that I took him out of the water. But yeah, he looks great to me, no scars, nice full tail. Sometimes they will have blunt tails and that's usually from predation or sometimes the crayfish will even chop them a little bit. And that happens even without us trapping. We will measure the mass of the snake. And we will also measure the length, both from the snout to the vent, which is this right here. And then the vent to the tail, to give us an idea of how big the snake is and can help us determine the overall growth rate of the population and how big the snakes are. We will also mark each snake. This actually looks like a new snake. So, this is a snake we've never captured before, which is awesome because we've been out here trapping for 20 years and we're still catching new snakes, which means that the population is still growing.
Anna Jordan: And that's really good to see. We will also give them a pit tag, which is the same as you would give a cat or a dog, a microchip. And that lets us know, in case the brand fades a little bit, that we know we have the same snake. Because they are a listed species, obviously we really care about how their population is doing. And one thing that we found actually is that the presence of rice fields not only increases the possibility of giant gartersnakes being present in an area, but it also increases the probability that they will stay in an area year after year. And that's directly affected to the proportion of rice in an area. I'm really optimistic because, after that drought ended and farmers are able to grow rice and there's more water available, we've seen that population start to bounce back. So, California will continue to have droughts, but as long as we're able to keep that water available, then giant gartersnakes, I'm really optimistic about their population increasing.
Jim Morris: They are a key indicator of the ecosystem, I imagine, because they interact with so many other species.
Anna Jordan: They are a very important of the ecosystem. Almost every species in an ecosystem is important. And that includes the species that humans may not necessarily like, but giant gartersnakes are really important in keeping pest populations down. And if you remove one species, it affects everything else. So you really want to protect the entire community and not just the ones that you think are cute. Though personally, I think giant gartersnakes are very cute, especially for snakes.
Jim Morris: I have to tell you, I was slightly disappointed when I first heard the name giant garter snake, because as a fan of B movie monsters, Anaconda comes to mind, 1997, J-Lo, John Voight, Ice Cube and an Anaconda, the size of a Winnebago. And that's not the case here, but are they still giants in their own world, if you will?
Anna Jordan: Honestly, I was a little bit disappointed the first time I saw a giant gartersnake as well, because you hear the word giant and you think these giant boa constrictors, they are giant for gartersnakes. They actually did used to get larger in the southern portion of their range. But due to habitat loss, they have been extirpated, which means they are no longer present in that southern portion. Up north, they do still get pretty big. They can be about three to five feet, but that's not really as giant as you would think.
Jim Morris: Do you have friends that have disowned you or do they think it's cool what you're doing, or is it a combination?
Anna Jordan: I think it's a combination. I've had friends who are super eager and are like, "Oh, I would love to come out with you and get out and see those snakes." And I've had friends who, like I said, will go, "Why? I don't understand what you're doing, but as long as you keep them away from me." And usually those people who don't want to know about snakes, I take that as an education opportunity because a lot of people who don't dislike snakes have never held a snake, have never seen a snake. Their exposure to snakes is these kind of horror movies or rattlesnakes, which are dangerous. But, especially in California, the only venomous snake we have is a rattlesnake and even rattlesnakes don't want to bother you. They probably want to get away from you as much as you want to get away from them. So if you leave them alone, you will be totally fine.
Jim Morris: What do you like about them?
Anna Jordan: They are just a really cool species. And honestly, I think part of the reason that they're unloved is like I said, that lack of education. And so the more I learn about snakes, the more I love them and especially giant gartersnakes, they are the sweetest, most docile snakes. And even their musk doesn't smell that bad, which is kind of that smelly predator defense. I've had my first project manager when I joined the crew actually said she loved it. And once a guy gets perfume, which is their scientific name, I wouldn't go that far, but they are just very lovable snakes. And they're fascinating creatures that are kind of unlike anything else. And I think that's what makes them my favorite animal.
Jim Morris: And you would be a big advocate, I suspect, for keeping rice in production?.
Anna Jordan: Yes, a hundred percent. Without rice fields and rice production, these snakes would go extinct.
Jim Morris: I'm also speaking with Allie Essert is with the US Geological Survey as well. And Allie, how long have you been working with snakes?
Allie Essert: I actually started working with giant gartersnakes when I graduated from high school. I started volunteering after that first summer, and it is a really, really strange job. Most people are shocked or sometimes even creeped out, when I say that I spend all day at work, trapping snakes and handling snakes, looking for snakes, but I love this job and I'm so happy I've been able to do it for so many years.
Jim Morris: It's interesting too, because we're not very far from Sacramento, yet we have rice fields which surprise people. And then we also have a threatened snake species out here. So you probably can have some great conversations with people.
Allie Essert: Oh, definitely. Even before I got this job, I had no idea that there were snakes even out here and I didn't know snakes used rice at all, and being so close to Sacramento, it's kind of crazy that they're just next door neighbors with us. So, water for giant gartersnakes is super, super crucial. During the active season, they spend probably the majority of their time within five meters of water. So even having the water out here is really beneficial for them. And then once the rice fields are flooded and the vegetation grows in, they also are able to use that as kind of a surrogate wetland habitat.
Allie Essert: Rice helps support prey populations like bull frogs and other types of fish that the snakes eat. And, it also allows the snakes to move between the landscape more easily. They prefer to move in the water then moving across any large terrestrial space, because they're kind of more susceptible to predators across the terrestrial landscape. So having the rice here allows them to get in between canals. It gives them more area for hunting and it really helps support their populations where wetlands are not available to them.
Jim Morris: Now, I believe your project coming up at school and explain this to me, involves telemetry with snakes. So tell me a little bit about what this is all about and how this will help the giant gartersnake.
Allie Essert: For my project. I am focusing mainly on telemetry of snakes. So studying kind of their movement behavior and how they're using the landscape, what type of habitat features they're selecting. And one thing that's really helpful with telemetry is we also do a lot of snake trapping, but we're only really seeing a snapshot of what the snakes are doing. And it's not as natural of an environment because they're caught in the traps and we don't know how they got in there, when they got in there. But telemetry is nice because it allows me to kind of track exactly where the snakes are located before disturbing them.
Allie Essert: So I'm able to see what kind of substrate they're using. Are they underground? Are they under a certain type of veg? It also lets me see how much they're moving during different seasons of the year at different temperatures. So, it kind of gives us a look at their ecology and behavior that we really can't get in any other kind of sampling scheme.
Allie Essert: They've been implanted with a radio transmitter. So it looks about the size of a double AA battery, and it actually goes inside the body cavity of the snake and has an antenna that kind of runs down. And each transmitter has a unique frequency, and that's how I'm able to use this antenna and receiver later on to pick up on the specific frequency of the snake and help zero in and locate them later on.
Jim Morris: Interesting. So technology is really helping and you also mentioned GPS technology, global positioning system. Tell me a little bit about how that helps.
Allie Essert: So, we use GPS points at where the snakes are located and then we also will take GPS points around the surrounding landscape. And we ultimately use these points to kind of get an idea of the total home range of the snakes. So kind of how much space each snake is using.
Jim Morris: When you talk with your friends, do some disown you or do they think it's cool that you handle snakes?
Allie Essert: Most think it's cool, but they would agree that they would never want that to be their job. And it's actually kind of comical because I love snakes. I've worked with them, I've had them as pets and I have absolutely no fear of them. But my husband is terrified of them and he agrees that he could never do the job that I do.
Jim Morris: So it sounds like this has been a passion for a long time. Have you always liked animals then?
Allie Essert: I've always liked animals. I was always the kid, just the young kid who was picking up frogs out of the ponds and showing weird bugs to my parents and relatives. So, I've always loved animals. And then when I got an opportunity to work with snakes, they've quickly become one of my favorite animals. I mean, even the mere fact that they do so many things with no legs, as weird as that sounds, it really fascinates me. I think snakes just have a really interesting, curious personality and I really enjoy working with them, especially giant gartersnakes. They're one of the most docile, friendly snakes of the snakes in this area. And for all the people that say they don't like snakes, I argue that point with you probably don't like pest species, either. And snakes do a lot to kind of keep pest populations down and they help just to regulate the ecosystem as an aquatic predator.
Jim Morris: You can find out more about the giant gartersnake and all of the wildlife and rice fields at our website, calrice.org. We have hundreds of photos and videos available, and we will keep you posted on the latest developments and helping solidify the giant gartersnake population. That will wrap up this episode of Ingrained. Thank you so much to Anna and Allie for their time and fascinating comments, what interesting research they're doing. A reminder to go to podcast.calrice.org, where you can subscribe and listen to past episodes. And we would love to hear from you. We invite your questions and comments. Thanks for listening.