The Serengeti Rules: The Quest to Discover How Life Works and Why It Matters [transcript]

Written by Christopher Kelly

Feb. 7, 2020


Chris:    Well, Dr. Estes, thank you so much for having me today in— where are we— UC Santa Cruz in California. I'm looking at the ocean as I speak. A fantastic location to have your office. Tell me about working here. How is it? 

Jim:    You know, it's kind of a dream in a way. I mean, this is a beautiful place to live. It’s an interesting institution. I was very fortunate to have alighted here, you know. Yeah, it's been great. 

Chris:    Tell me about how you first became interested in biology.

Jim:    I mean, I have always been interested in it to some degree as a child. I did a lot of just prowling around the canyons of San Diego where I grew up, but I became interested in biology as a freshman, a first year student at the University of Minnesota. I went to University of Minnesota on a baseball scholarship. I was interested in sports and I went back. I had no idea what I was going to do. But as a first year student, I took general biology and I loved the class and that was it. I said this is what I want to do. 

Chris:    And there was never any question you'd stay in academia. 

Jim:    Oh, I think there was. I didn't know where I would head. I really had no vision for a career. I just knew that I was interested in biology and I was thinking about a variety of things like most everyone else in my position at that time was. I was thinking about professional schools, medicine, or something of that sort. I was thinking of pharmacy at one point. And I had an opportunity. I had a family member, my mother's cousin's husband whose name was Irvin Bus, and he was a professor at Washington State University. And I became intrigued with what he did. He was a naturalist, a wildlife biologist. And as I was getting on into college, I wrote him at one point and said, “I'd like to talk with you about a career in ecology and wildlife.” And he immediately wrote back and said he knew me and he knew the family. And he said, “If you'd like to come here and do a master's degree to kind of get moving down that direction, well, I’ll have you in.” So, that was the beginning of it. 

Chris:    What year was that? 

Jim:    That was 1967. 

Chris:    That's amazing. 

Jim:    1967, I graduated from the University of Minnesota. Fall of `67, I started as a master student at Washington State and that was really the beginning of it. I think my life at that point was fairly well set as far as a general life course. 

Chris:    And what was it about ecology specifically? I mean, surely even at that time biology was a huge field of study. What was it about ecology then? 

Jim:    You know, it wasn’t ecology so much. I was also very interested in physiology. And Washington State had a good program in physiology and had some very good professors, some good courses, people who were doing interesting research. And I was probably equally interested in physiology at that time. I didn't really become interested in ecology until 1970 at least in a serious way. And in 1969, as I was finishing my master's degree, I was facing the draft. Vietnam War was raging on and everybody who wasn't married or didn't have some reason for deferment was essentially looking toward having to spend some time in the military. And so, I was called for a draft physical in the spring of 1970. And I went up to Spokane, Washington, took a physical, and failed it. And it was an absolutely unexpected thing. I had knee that had never bothered me, but snapped. And that snapping knee apparently was enough to dissuade the physician for even thinking any further about having me as a potential member of the armed forces. And so, they rejected me right at that point. 

Chris:    And how did you feel about it? 

Jim:    I was in shock. I was thrilled. I mean,— 

Chris:    That’s amazing.

Jim:    …I did not want to be part of the military. I had no interest in going to Vietnam. I was, like most of us at that point, pretty lukewarm about that whole endeavor, but I also was— I knew I was a citizen of the country. Those are things we did. I was in no way not gonna do it, but it wasn’t something I was looking forward to.

Chris:    Right. 

Jim:    So, I thought at that time I’ll do my 2 years. Hopefully, I’ll survive that. And when I get back in the early `70s, I’ll then begin my career again. But that general imagined pathway was short circuited when I failed the draft physical. And almost immediately within a month or two of that time, I received a note from one of my other professors at Washington State University who is a consultant. He was a statistical ecologist and was a consultant with what was then the Atomic Energy Commission. And he got in touch with me and said, “You know, I'm one of the consultants on the Amchitka Island Project.” The Amchitka Island Project was a project that Atomic Energy Commission (the AEC) was engaged in for underground nuclear testing of very large nuclear devices. 


Chris:    Uh-huh. Is it somewhere in the Pacific? 

Jim:    This is way out in the Aleutian Islands. This is what got me to the Aleutian Islands. This is what got me connected with sea otters. So, he said they want somebody to go out there and spend a year or two working on sea otters and to do an honest assessment of the impacts of their activities on these animals and on this population, you know. It's a politically and socially very sensitive issue. There were some interesting history that led up to the Atomic Energy Commission being sensitive to this issue at this time. This was really kind of the beginnings of the environmental movement at that point. And you know, I thought about it for a nanosecond and said, “Sure. I'll go right.” 

Chris:    That’s right.

Jim:    So, I went out and that got me to the Aleutians. That's what got me working on sea otters. I'd never even seen a sea otter. I was not a marine biologist. I had no background in any of this sort of thing, but that was my entrée. And working with the animals, I began to learn about them. And in the course of doing that, I spent a fair amount of time diving and looking at their environment because they live in this coastal ecosystem and they forage on the bottom of the ocean. And so, I needed to go and look at the bottom of the ocean to understand the places that they lived and what they were doing. And so, I started doing that. And about a year later, maybe half a year to a year later, I happened to meet Bob Paine who is a young assistant or associate professor at that time at the University of Washington. And he came to Amchitka Island as a committee member of one of my friends who— and I think Bob actually went to the Aleutians as a boondoggle just to see, you know, another part of the world. And we met and we talked. And I was struggling at that time with what I wanted to do with otters. And we had a brief discussion one evening in which he asked me “have you ever thought about trying to explore the impact that these animals are having as predators in the system” and I never even thought about it, but that was the beginning of the rest of my career really. And there were a fair number of details that ensued, but that's how I got into ecology. That’s how I became interested in sea otters and kelp forest ecosystems. And most of the rest of my professional life has unfolded from that. 

Chris:    Can you tell us about the Aleutian Islands? What is it like there? 

Jim:    Well, it's a very stormy place. It’s the geographical boundary between the Bering Sea and the North Pacific Ocean. It's foggy, damp, stormy. The islands are treeless. They're also very precipitous, very mountainous. There are volcanoes. There are volcanic islands. So, it's a spectacularly beautiful landscape, but very stark and daunting in some ways because it's a dangerous environment in the sense that it's cold and it's stormy. And so, those are the two major detriments or the major risks or the problems that one has to confront in working out there. There are really no dangerous animals out there. There's no disease. There’s nothing else.

Chris:    Are there any people? 

Jim:    No people. 

Chris:    Oh wow.

Jim:    No people. There were people, the Aleuts, the native people that lived in that part of the world, but they were essentially eliminated during the maritime fur trade. 

Chris:    Oh wow.

Jim:    And so, Amchitka Island was a staging area for what was going to be the invasion of Japan in World War 2, but the atomic bomb was developed before that happened and by the end of the war. So, Amchitka had a huge infrastructure that was created by the navy and the army for this planned invasion of Japan and that stuff was still all over the place when I was there. Most of the other islands have some— There’s some remnant of military activity virtually everywhere. But for the most part, they appear to be a complete wilderness. There's nobody there. You see nothing. You see almost no signs of human activity other than things that wash up on the beach from fishing boats and debris [0:09:12][Inaudible] That's pretty much all you see. 

Chris:    Well, it sounds like it might be a marine paradise, but you mention the fur trade there. Can you tell us about that? 

Jim:    So, the fur trade began in 1740-1741. And it began with the Bering expedition. The Bering expedition was an effort that was commissioned by the tsar to try to find a route across the Arctic, a shipping route across the arctic. And so, Vitus Bering and his small group of vessels headed off to the east out of Kamchatka knowing nothing of what the North Pacific looked like at that time, knowing nothing of what was to the east. And they sailed across the North Pacific. They ran into Southeast Alaska. That's where they made landfall. They then turned north to head home and sailed across the Aleutians on their way back to Kamchatka and were shipwrecked in the Commander Islands, which are the western most of the Aleutian archipelago which are now Russian territory. 


    And they discovered that the Commander Islands had these vast fur resources for seals and sea otters and that started the fur trade. And that began a period of 150 years of exploitation, and exploration, and development, and imperialism. And the Russians essentially claimed Alaska as their sovereign territory at that time. U.S. then purchased. It was Seward’s Folly. The Secretary of State Seward bought Russia from Alaska. But by the time the U.S. had purchased Russia from Alaska, most of the sea otters have been wiped out. 

Chris:    Wow.

Jim:    And by the early part of the 20th century, there was some concern that the species have been hunted to extinction. They were not even known to exist anywhere, but there were a few small remnant colonies that survived here and there. And those remnant colonies grew with protection that was afforded by an international treaty that was put into law to protect both sea otters and fur seals, both of which had been extensively overharvested.

Chris:    Uh-huh. And was that just in the Aleutians Islands up north or was it down here?

Jim:    Everywhere.

Chris:    ‘Cause I see them sometimes playing in the water when I go down to Bonny Doon Beach. 

Jim:    So, one of the surviving colonies was off Bixby Creek along the Big Sur Coast. At that time, it was a very remote area. There was no road or anything down there. And so, there was a small number of animals that survived there and there were a dozen or so other sites across the North Pacific in retrospect now that we know had harbored some sea otters. And by some, I mean maybe 30 to 50 individuals survived. And Amchitka Island was one of those sites. And so, that population was one of the early populations to have recovered over the next half century. It grew and became very abundant. But there were other islands that had been occupied by otters from which they had been completely exterminated. And so, when I came on to the scene in the early 1970s, the situation was one in which we had islands that otters had recovered on and other islands where they had been abundant, but where they had not recovered. They had been hunted to extinction and they simply had not just by the vagaries of history recovered on those islands. And so, that's what excited me when I had this discussion with Bob Paine when he asked me the question of “Have you thought about what impact these animals might have on the ecosystem?” I thought “Well, here is a perfect way to look at that.” I mean, we have this place where they once occurred and they have been experimentally removed from some of these sites. 

Chris:    Well, how did Bob know to ask that question? Can you talk a bit about him and his work? 

Jim:    Yeah. Well, he asked the question because he had become interested in predation as a process. He became interested in predation as a process because he was a graduate student at the University of Michigan in the late 1950s. And he was a student of a man by the name of Fred Smith. Fred Smith was a colleague of two other people at the University of Michigan, Nelson Hairston and Larry Slabodkin. And Hairston, Smith, and Slabodkin wrote a paper in 1960, the title of which was something like predation and population regulations. Very short little paper. But in that paper, it put forth a hypothesis which has subsequently become known as the green world hypothesis. And the green world hypothesis posed that the reason the world is green is because predators keep herbivores from eating all the plants. It was as simple as that. Paine became compelled by that. He was a student in one of the classes and became very interested in that idea. That was also a time when the conceptual infrastructure of ecology was really built around 2 things. One was competition as a limiting process as opposed to predation and the other was the equality of species. And so, Paine’s two major contributions, which grew out of his work on sea stars that was the beginnings of his own scientific career when he became a professor at the University of Washington around 19— I don't know when it would have been, but probably the early 1960s. He got on to this idea from his starfish removal experiments of, one, predators really matter. He demonstrated that experimentally by removing the starfish. 


    And that became one of the most foundational experiments and studies in all of ecology. And he also put forth the idea that all species are not created equal and that led to the keystone species concept. As so, he had these ideas in his mind when we met in 1960. 1960 was 10 years or so after he had started to work on this stuff. I didn't know who Paine was at that time. His scientific influence in the world was just starting to sort of gain momentum. And I was just fortunate enough to meet him and for him to kind of impart some of that wisdom on me at that particular time. Had I had to learn about my own, it would have been too late. And I would have been gone, but I had been there and gone. And I would have probably never thought of these things, but that’s how that all started. 

Chris:    Okay. I’m starting to get a sense of why your memoir is called Serendipity. I have here in front of me a book. The title is Serendipity. 

Jim:    And everything. I mean, from failing my draft physical, to winding up in the Aleutian Islands, to meeting Paine, to all of these other things. It’s all such a fortuitous reconstruction. In retrospect, it's very clear. But in prospect, it's not something anyone would have ever thought to— 

Chris:    Nah, never could have predicted it.

Jim:    Never. 

Chris:    Talk about the starfish experiments then. I thought this was a really beautiful piece of science, you know. You look at some of the papers I read today and you need statistics and all this like fancy math in order to be able to understand whether or not there’s something there. And I look back at this experiment that I saw in The Serengeti Rules documentary that you can find on PBS Nature or on the BBC iPlayer. And I thought “Wow. That is a wonderfully pure and beautiful piece of science.” Can you explain the experiment? 

Jim:    Yeah. So, the experiment really came about because when Paine took his first faculty position at the University of Washington, he began looking around for a place to work. And he hit upon the outer coast of Washington. He saw this amazing intertidal community and he said, “Ah, this is the place that I wanna work.” And so, he spent a little time familiarizing himself with the species and who ate whom and all of that sort of thing. And he discovered the starfish who other people of course knew existed out there, but he discovered the starfish and he must have thought “Here's my first experiment. I'm going to simply remove the starfish and see what happens.” And so, he simply went down to the intertidal. He found a couple of little places where there were a lot of starfish, and he took a starfish out of some of them, and he went one out there every month. And he did this for a year, or two, or three. He just went every month and he would take the starfish and peel them off the intertidal and throw them back out in the ocean. And by doing that, he maintained a small stretch of intertidal habitat free of any sort of impact of starfish. And almost immediately, he saw the prey of the starfish start to become more abundant. And very soon thereafter, he noticed that one particular prey species, the sea mussel, was becoming so abundant that it was excluding other species. And so, he then discovered that not only was a sea star having a limiting effect on the mussels, but by doing that, it was providing the opportunity for other species to live in that system. And when the stars were taken out, those other species disappeared. That was his major contribution. 

Chris:    And so, what did the tide pool look like once all the starfish had been gone? I think it’s worth noting how long did Bob go back to those tide pools? 8 years. 

Jim:    He did it for a while. I think his first paper was— You know, he actually continued maintaining the experiments right up until the end of his life. So, he started working— You know, he changed sites once or twice over that period of time. He wound up at a place called Tatoosh Island, which was a fairly isolated spot that the public did not have access to. And so, he did a lot of his work out of Tatoosh. But his initial experiments were not down there. They were done in Makah Bay, which is a place that anyone can go down to. Very close by. You know, I think probably by the end of the second or third year, he realized that he was on to a very major discovery and there was no obvious end point to it. As I said, he continued to maintain some of these experiments for long periods of time afterwards. 

Chris:    But one could imagine that his motivation increased as he realized he was on to something really important.

Jim:    I think he must have. You know, I knew him very well. I think that he recognized that what he was thinking about and what he had discovered ran very counter to the general intellectual and conceptual underpinnings of ecology at that time.

Chris:    Right. And what was that dogma that existed at that time?

Jim:    Competition. Everything was driven by competition. 


Chris:    Right. 

Jim:    And that all species were more or less equal in that competitive network. 

Chris:    Right. And so, this is where it comes. The adaptation of famous George Orwell all animals are equal, but some are more equal than others. 

Jim:    Exactly. And so, his view was. And he really didn't have a whole lot of evidence at that time other than he had tried to do the same experiments removing other species from the system, not just starfish, but some of the other species, and didn't get any sort of the same sort of effect at all. And so, that’s what led him to the notion that the starfish were super important compared with other species and all species were not equal in the system. Some are more important than others. Some are more equal than others so to speak.

Chris:    Right. And so, after days, weeks, months, years of clearing out the starfish, you’ve got tide pools, just a monoculture of mussels.

Jim:    Monoculture of mussels. Yeah. 

Chris:    That’s incredible.

Jim:    Yeah.

Chris:    And so, back to the sea otters, what happens? Well, that’s interesting. Right? So, have you thought about the sea otters as predators? What happened next? 

Jim:    Well, Bob was thinking that if sea stars are predators and I think it must have dawned on him that there would be other species in the world that would do the same thing— I couldn't read his mind at the time. He didn't say it this way. But I can’t imagine that he was thinking anything other than “Why don’t you try to do the same thing with sea otters? Is there some way you can do it?” And of course, you know, the concept was interesting to me. The opportunity was interesting to me. The ability to do it experimentally like he did with sea stars was something that was completely off the table. It's not something we could do. You can't go out and take otters out of the system anymore or put them back in. It was just, you know, logistically, ethically, legally impossible sort of thing to do, but history had created this wonderful experiment. I didn’t even have to wait a minute. All I had to do is go to a place where otters had once been, but were now absent, and compare that with what I had seen it at Amchitka Island where they had recovered. And so, I did that almost immediately. We had our meeting. I forgot when it was. It was probably in June. I think probably July or August I went out to Shemya Island, which was a couple of 100 miles to west of Amchitka where there were no otters. The second day that we got in there, I went down to the beach the next day. I put on my dive gear. I looked in the water and the story had unfolded with in less than a second. It was so obvious how different these places were. The system that I saw at Amchitka Island was just covered with kelp. Diving there, the whole sea floor was covered with kelp. There were urchins around, but not very many. And they were small and they were more in deeper water than shallow water. And when I stuck my head in the water at Shemya, there were no kelp at all and urchins were everywhere. Big ones, very abundant. And they had eaten all the kelp. 

Chris:    Okay. So, that was gonna be my next question. Like what’s going on here? 

Jim:    And so, here we have this obvious situation where what this led me to, the interpretation that I made almost immediately, I knew that otters ate urchins. I knew that urchins ate kelp. Everyone knew that. And so, the obvious interpretation was you take the otters out that were eating the urchins. The urchins become abundant and they’ve eaten all the kelp. So, that became an example of this thing called trophic cascade that is an impact from a predator to its prey to the prey of the prey. 

Chris:    And what’s that like? Can you describe the feeling? You’re there in your wet suit, and you got your mask on, and you’re under the water, and you have this moment of realization. Do you feel like “Oh my God, I just need to get back to the boat so that I can get back to my desk so that I can start typing this stuff up?” What is it like? 

Jim:    Well, I guess 2 things came to mind. I mean, one was “Oh my God.” You know, it was the most exciting professional experience I've ever had far and away. I mean, I realized I was a bit cautious because I thought “Oh my God, if this is going on, this is a big deal.” And no one’s ever seen anything like this in nature before. It was different from what Paine had seen, you know, and his processes involved in his experiments, which were still not that well known frankly. You know, this was 1970. His foundational paper was published in 1966, which was mostly an idea paper. And his empirically based studies were not published until later in the `70s. And so, the stuff was not in the literature at that point. I didn't know anything about it. And I was just thinking. I really had very little feeling for the conceptual foundations of ecology. But from a natural history perspective, I know this has to be a big deal. Who wouldn’t find this interesting? That was my reaction. And I thought “Ah, I have succeeded. You know, I've done something really useful.” 


    That was amazingly exciting. I began thinking a lot. My main thought was how do I document this. We're only here for a week. Seeing something is one thing. Documenting it as a scientist is something else. 

Chris:    Remember, this is in the 1970s. There were no GoPros attached to everybody’s chest. Right? 

Jim:    No. There weren’t. I mean, we did take some pictures. We had Nikonos cameras at that time. They were film-based underwater cameras. So, you know, we had some photographs. You could see what it looked like. But still, there had to be data. And so, my first thought was how do I go about documenting these different patterns that I see at these different islands. They’re very obvious to my brain. They’re obvious to my perception of nature, but just those words will not resonate with people. So, they need to see data. They need to see some. So, I mostly was thinking I have about another week left here and I don't know if I'll ever get back. What do I do? And so, I mostly was thinking about that at that particular time. 

Chris:    So, what did you collect? How did you synthesize data to— 

Jim:    So, I just decided, you know, the simplest thing to do is to take a quadrat and start tossing it around on the sea floor and measure how many urchins there were, how many kelps there were, and what the species of kelps were, and what the size distribution of the urchins was. And I just went out and dove around the islands and then I went back to Amchitka where I had been working and I did the same thing. And then I came home a year or two later after having done that. I actually did have a second year to go out to Shemya Island and another otter-free island, Attu, which was a little further to the west. I went home in 1972-1973. I finished my field work out there. And in 1973-1974, I wrote an initial paper on this comparison. It was paper published in Science in 1974. That was my first paper. 

Chris:    And how was it received? 

Jim:    It was received well I think.

Chris:    Did it go against the prevailing wisdom at that time? 

Jim:    I think it did, although I was not particularly aware of that. 

Chris:    Did you have to go through peer review and all that?

Jim:    I was a graduate student, you know. I mean, I went to some of my professors. I was then at the University of Arizona. That’s when I was a graduate student. And I went to a couple of my professors and I showed them this paper. And you know, the reaction at that time was I think fairly— It's hard for me to recall. I didn't get a lot of strong reinforcement from them, but from my colleagues, from the other graduate students at Arizona and in particular at the University of Washington and in particular one person who was a man with the name of John Palmisano. John lives in Portland now, but he and I did this work together. He and I went out to Amchitka Island or out to Shemya Island together. We put this paper together. And he probably more than anyone else was the individual that I think— He recognized how important it was going to be way more than I did, but we wrote this paper. He came down to Tucson for a week. We wrote the paper together. We submitted it to Science. It got published and then I started getting reprint requests because that's what people did in those days, you know. You didn't have PDF. People didn't have access to the internet.

Chris:     I see.

Jim:    So, they would see the journal. The journal will come out on Friday and then they would send these little postcards for papers they were interested in. And so, my mailbox started filling up with these things. And I had ordered— I don't know— 100 or 200 reprints of this paper when it was published and they were gone like that. 

Chris:    Can I just pause to emphasize that like the visceral response that that must invoke compared to how science is done today, right, you might not even— you know, downloads— You might see that on some database number somewhere on a webpage, but it’s not the same as what you just described, right? 

Jim:    There were no age factors. You know, we never thought about how often a paper was cited, but I knew I was getting all of these reprint requests, these little postcards. And the postcards were made up. Everyone had them and they had your address on them and then it just had a little place in there, please send me a reprint of, and you’d write the paper in there. And then I will take these things and have it reprinted on an envelope and drop in the mail. And that’s the way things happened. And the faculty at the University of Arizona then started— People started coming into my office saying we’d like a reprint of your paper and it became clear to me that they were interested in what I had done. I started to feel more and more as though this was an important contribution. 

Chris:    And so, had Bob Paine been talking to other scientists too or other people doing different— well, similar experiments in different ecologies, in different ecosystems?

Jim:     I was probably one of the first. He did have a graduate student.  


    He had several students. One was a person named Paul Deighton. And Paul was several years older than me. He’s several years older than me. He is still living. He was a professor for all of his life down at Scripps after he finished his graduate work. So, Paul's work was followed up very closely from Paine’s. And he had several other students that worked in the intertidal community in Washington. When I went to Paine and showed him— You know, I went back to his office at the University of Washington when I was in Seattle. And you know, this was a year or two after we had met. And I said, “Here's what I did. What do you think?” And he was sort of lukewarm about it. At least that was a sense that he gave me. And he was lukewarm about it because not only was he an advocate of predation being important and these processes that emanate from predators and systems, but he was also a very strong proponent of experimentation. And what I did was not an experiment per se. It was not something I did purposely. It was not controlled. And he made it very clear to me at that time that the power of what I'd done as an example of good science was always going to be limited. 

Chris:    Right. Versus what Bob Paine had done. You mentioned that there were controlled tide pools. Right? He didn't throw away all the starfish.

Jim:    Right. But over the years, he softened quite a bit on that view. And we never really followed up on that early discussion over the years of meeting up and talking together, but I knew. You know, I just knew— 

Chris:    Well, what happens when you put the sea otters back? You can answer that question, can’t you?

Jim:    Sure. So, we've seen that happen. Not only have we seen what happens when you put to sea otters back, but we see what happens when you take them out again because in the 1990s we had a collapse of the sea otters. After they had recovered almost a century following a century of protection, there was a monumental change in that system that caused the otters to disappear. And the change was that killer whales entered the system and ate the otters. And we saw that, you know. I was working out there at that time and I saw the killer whales come. I saw them eat the otters. I saw the otters disappear. I saw the urchins expand. I saw the kelp disappear. So, we published that paper also in Science in 1998. And it was I think a really powerful reaffirmation of process even though there was something else going on in the system. There was a new trophic level added. The otters were no longer the apex predators. They’re no longer on top of the food web. The killer whales had come in and become the top of the food web and that opened up a whole new line of inquiry about why did this happen. 

Chris:    That was gonna be my next question. What the heck? Why did that happen?

Jim:    Well, I didn’t know. I really didn’t. I was skeptical initially that killer whales could have such an impact on otters. But after a few years of watching the system, it became fairly clear to me and to my colleagues that there was very little doubt that that's what happened out there, but it did leave the question unanswered as to why. My initial thinking about why it happened was that these killer whales are predators on other species of marine mammals and there had been a comparable decline a decade earlier by stellar sea lions in that system. And so, what I was imagining at that time was that the sea lions had declined for some unknown reason. That the killer whales had been eating the sea lions no longer had sea lions to feed on. And so, they began eating the otters. They had expanded their diet to include otters. That's what I thought at that time. That's what I thought and what my colleagues and I were thinking was going on in 1996, 1997, 1998 when we published that paper. At about that same time, I met another important person in my life by the name of Allan Springer. Allan was a research professor at the University of Alaska. And in probably 1997, I got an email from him or a letter from him saying I've heard rumors that you're doing something with killer whales and otters and can you tell me a little more about it. And we had our paper almost written at that time. I didn't know Allan. I knew who he was, but I didn't know him personally. So, I sent him the paper he and he sent back some helpful comments. It was obviously getting his mind going in certain directions. So, we met. We got together a couple of years later and he said, “I have an idea I wanna pass by you.” And we had a breakfast meeting and I was in Fairbanks for a meeting and we met up. And he showed me some data that he had been assembling along with some of his colleagues on the history of whaling in the North Pacific Ocean. 


    And what those data demonstrated was that the great whales of the North Pacific and the Southern Bering Sea that were members of that ecosystem that we were working in (sort of defined very largely) really didn't start to decline until after World War 2. It was World War 2 at cessation of the war effort and the expansion of fishing and whaling by the Japanese and the Russians that wiped out the whales in the North Pacific. And Allan, the data that he had— I don't know where he got these initial data, but he had them kind of plotted out on these sort of rough initial plots, you know, it was very clear that you could see where— how many and where the whales had been taken. And he, after showing me this data, essentially said something like this. What do you think of this idea that these killer whales were essentially sort of buffered from feeding on other marine mammals in the system by these vastly abundant and large, large whales that they were feeding on? Once the large whales were taken out, it caused these killer whales to expand their diets and they started feeding on species that were no longer sustainable.

Chris:    So, fallback foods.

Jim:    Right. Like harbor seals, and sea lions, and otters. And one after the next after the next, those new prey species collapsed. And what we saw was the otters collapsed. 

Chris:    Right. So, this is the trophic cascades. 

Jim:    Well, this is what was called the megafaunal collapse hypothesis leading to the trophic cascade because the key interaction between the great whales and the killer whales was that the great whales were at least by this hypothesis an important source of nourishment to the killer whales. And what threw this system out of whack was taking that important source of nourishment to the killer whales out, but leaving the killer whales essentially undisturbed. 

Chris:    Uh-huh. Why were the fishermen taking the whales at that time? I mean, they're not using the oil for— 

Jim:    Oh, they were.

Chris:    …oil laps or whatever.

Jim:    Well, not so much oil lamps anymore, but food. 

Chris:    Right. Interesting. 

Jim:    And so, it was mostly a meat— You know, Japan has always had— and Russia— So, it was mostly protein. I don't think it was oil based so much, although I'm sure they still rendered the whales. You know, I don't know the details of exactly what was done with the carcasses at that particular point. 

Chris:    The reason I mention it is I remember Matt Ridley wrote about the evolution of everything, the electricity. The invention of electricity was a good thing ‘cause it meant that we didn’t have to take whales and render their oil for power. Right?

Jim:    Yeah. And the discovery of petrochemical resources too, you know. I mean, prior to the discovery of oil and the use of fossil fuels, the whale oil was used to— 

Chris:    That’s exactly it.

Jim:    …generate light and burn as an oil source and for lubricants and all kinds of things. So, those things did change, but whales still remain valuable. They remain valuable mainly as a source of meat. There were a lot of them. They were big and they were very valuable. And they were very unsustainable, you know. They don't have a high reproductive rate. And so, when the fishery started and they began exporting these things, it didn't take very long to completely wipe them out. And so, Allan’s hypothesis was that it was the removal of whales that caused this collapse in the sea otters. And I had not thought about that. And my reaction was stunned silence initially. We had some follow-up discussions and I remember very explicitly writing him a couple of days later and saying, “Do you really believe that?” And he wrote me back and said, “No, but I don't not believe it. I think it’s a really interesting possibility.” And I thought that's the proper way to be looking at this. And he and I agreed at that time we would sort of join forces and try to approach the hypothesis and test it and look at it from both the evidence for and evidence against and try to explore and understand— 

Chris:    Can you shoot it down? 

Jim:    …whether that's what happened. And we did that. We spent about a year doing that. And we came to the conclusion it was probably right.

Chris:    Interesting. So, what happened? Did that lead to a change in global fishing policy? 

Jim:    No. What happened was that the paper was published in the proceedings of National Academy of Sciences in 2004 and it resulted— I mean, it kind of sent— I mean, it really was from my perspective anyway— It sent shockwaves through the world of fisheries and marine mammals. It was widely, widely known in the media and people were talking a lot about it, but the marine mammal community and the fisheries community were very skeptical and not only skeptical, but very hostile to the idea. 


    So, it resulted in— chapter if you read this book, the whale wars— that was a big fight over what really happened. And it was an ugly, nasty period. 

Chris:    So, what was the hostility? What was the objection? 

Jim:    Well, it's never entirely clear. I think the purported objection was that it was not consistent with the evidence, which we argued vehemently that it was consistent with the evidence. I think the truth is that it wasn't just a science issue. I think that it was a political issue. I think it was an issue of ego. And I think there was an issue of economics. And the ego part of it was that there was, you know, a whole bunch of other people out there that have been working on whales and killer whales and they hadn’t seen this and it was happening right before their eyes. 

Chris:    But it’s like what you said about Bob Paine and the starfish. It’s like not that people have not noticed the starfish before. You just like noticed a bunch of stuff with curiosity that nobody had noticed before.

Jim:    I just think that the idea of those kinds of things happening in nature still were not widely accepted especially in the marine sciences community. And the marine science community, and the oceanographic community, and the fisheries community, which was sort of the science base for people in the marine mammal community, just not thinking about these kinds of things as being important. They were thinking more in terms of physical oceanographic change being the main driver of everything. So, I think that was one of the problems. Another problem was money because the collapse of the stellar sea lion in particular became a very big deal. It became a big deal because the ground fishery of the Bering Sea and the North Pacific Ocean was the single most valuable fishery in the world. And if the collapse of the sea lion was a consequence of the mismanagement or overexploitation or for whatever reason an epiphenomenon of that fishery, then there were some major economic structures and social economic structures whose welfare was at stake and was at risk because the stellar sea lion was listed under the Endangered Species Act. And so, there was a law that would actually intercede that could have a big effect on the degree to which the fishery could continue to operate. So, as a consequence to that, there were a lot of people that were getting a lot of money to do research on that very question. 

Chris:    I see. 

Jim:    And if our hypothesis is correct, it would argue that essentially they were headed down the wrong path. And therefore, we shouldn't be spending all of that money on that particular approach to it to the degree that there was even a rationale or justification for putting so much money into working in that system. Ought to at least take a broader approach and ought to maybe be focusing on other issues. And I think that was very frightening because there were programs whose long-term existence were built on that support base. 

Chris:    But isn’t this the essence of science we were talking before we started recording about Dave Dima who is my neighbor and also an emeritus professor? Anyway, I set that aside for a second. In one of his books, he talks about how when he starts teaching students, they discover a hypothesis and they should be allowed to like spend time with it, and rejoice in finding it, and nurturing it and you can tell your friends about it and then your job is to shoot that hypothesis down. And the reason you should do that is so that you can move on to a more and better hypothesis. Right? Like should that not be true in this instance too? 

Jim:    I think so. I mean, my philosophy about how we learn is that we have ideas and that we look for both supporting evidence and contrary evidence. Supporting evidence is a limited additional power. 

Chris:    Exactly. Because you can never prove it right. You can only prove it wrong. Right? 

Jim:    But if you find something that is fundamentally inconsistent with it, then you've learned something important. And that was the approach that we try to take. So, we lighted up all of these potential hypotheses or explanations for what might have happened up in the North Pacific and then we took all of the data that we had on one thing or another that have been gathered by our own program and by others. And we lined all of these hypotheses up with what we knew about the system and we asked the question to what degree are the findings consistent with these various hypotheses or inconsistent. And where they were consistent, that was not terribly interesting. Where they were inconsistent, it was very interesting and we argued or we propose that where we find these inconsistencies we have learned a lot and we can exclude those hypotheses. And the only one that never fell off the table was this megafaunal collapse hypothesis. And that's really what led me to embrace it. It wasn't so much that the evidence in support of it was so powerful. I mean, it made a lot of sense. We simply couldn't rejected it. 


    And it was sort of the last hypothesis left standing in a world in which there just didn't seem to be any other reasonable explanations. 

Chris:    Right. So, so far, we've been talking about marine ecosystems yet the name of the documentary in the film was The Serengeti Rules. What’s up with that? So, were other people elsewhere in the world discovering these rules also held true on land? 

Jim:    There were various other people that were looking into the same kinds of processes. One of whom was Tony Sinclair. And Tony was a professor at the University of British Columbia. And he is working in the Serengeti. And Tony's work was essentially— He is still living, a wonderful ecologist to work on a whole variety of things, but probably best known for his work in the Serengeti. And his work in the Serengeti was built like mine on the sea otter, was built on a natural experiment. And that natural experiment was the invasion of rinderpest into East Africa. Rinderpest is a disease that is transmitted by cattle. It was brought in by cattle, but it spread into all of the bison, the native wild African mammals, and essentially wiped them out, in particular things like wildebeest, and buffalo, and a whole variety of other cow-like creatures that were in the East African Serengeti type system. 

Chris:    So, if you watch the next documentary and it features big cats, then it was probably in the Serengeti.

Jim:    Yeah. Yeah.

Chris:    I mean, I guess back then in the `60s, it wasn’t very known very well, but— 

Jim:    It wasn’t known very well. And in fact, what happened was that the various management authorities, and health authorities, and so on became aware that rinderpest was the problem, that it had a very strong limiting impact on these wild animals. And so, an effort was made to intercede and to essentially control rinderpest. And they were spectacularly successful in doing that. They essentially exterminated rinderpest from East Africa. All of these things began to recover and the ecosystem began to change in response. And that's what Tony saw. Though in a way, what he saw was the same thing that I saw except the key predator in his system was a microbe. It was rinderpest. It wasn’t a sea otter. It wasn’t a lion. It was a microbe.

Chris:    Oh, that’s interesting you say that then. So, you don't think the keystone species is the wildebeest. You think it's the microbe. 

Jim:    The predator in the system is a microbe. 

Chris:    Okay. 

Jim:    But everything else is exactly the same. The wildebeest are herbivores. They have an impact on plants that has all sorts of other impacts on the ecosystem. That was Tony’s story. That was essentially a big piece of his life work, that discovery. Sean Carroll, who wrote the book, simply happened to be in the Serengeti on vacation with his family. I believe fortuitously met Tony when he was there, learned about this story, and that's what prompted him to create that title for his book, The Serengeti Rules.

Chris:    Uh-huh. So, what happened when the wildebeest came back? The numbers went from— I mean, it was quite an extraordinary change, the number of wildebeest. Right? I remember it was like 200,000 to like 1.2 million or something like that. Would that not cause catastrophe for the ecosystem there in the Serengeti? 

Jim:    Well, it didn’t. It hasn't caused anything akin to what people would call a catastrophe. It has had big effects on the plants. It had a variety of impacts on the ecosystem. One of them was the removal of plant biomass that caused a change in the composition of the plant community. It caused the plant community to shift from being essentially a grassland community to sort of a mixed grassland, tree, savannah-type community. It had a big impact on fire ecology because the fuels that were driving hot frequent grassland wild land fires in the Serengeti were no longer available once this large population of herbivores repopulated the system. They also had a big effect on nutrient recycling. And this is perhaps one of the reasons it hasn’t created a catastrophe, is that by adding the wildebeest and other buffalo, but primarily wildebeest, back into the system in such large numbers, cycling a lot of nitrogen, and phosphorous, and other key nutrients back into the system at a much higher rate— 

Chris:    Through pee and poop. 

Jim:    Yes. Through urine and through feces primarily. 

Chris:    Right. And then you got this fear factor. Right?

Jim:    Yeah. Well, that’s another impact on the way that the animals behave and what they do. So, people are starting to see these same kinds of processes in other systems. We’re seeing the same thing with the bison. And so, at the end of the film, there’s this picture of the bison. And the implication for someone with a really nuanced understanding is that how different was the productivity and the dynamics of the tall grass prairie system when bison were running free and migrating in that system in huge numbers compared with now. 


Chris:    Well, that was gonna be my next question, is 150 years ago there were how many bison on the great plain. I’ve just been reading a book about the Comanche Indians and they talk about the bison and the fur trade that went on similar to the fur trade you talked about with the otters. And now of course, all the bison have gone. What factors that had on the ecosystem? Is there anything else? I mean, so, you look at Yellowstone and the reintroduction of wolves. What happened there?

Jim:    Yeah. I mean, there's a story there and there were almost certainly big effects. And those are kind of stories in their own that have been told in the past or work that is still ongoing. In fact, there was a very interesting paper that was just published probably 3-4 months ago on bison in Yellowstone and how they impact the recycling of nutrients, how that influences the seasonality of change in Greenup, and how that influences the migratory behavior of bison. So, bison are having an impact on themselves by enhancing the local productivity of these systems just like the wildebeest are doing in the Serengeti. So, this probably is a recurrent phenomenon in various systems that have lots of large migratory herbivorous mammals in them.

Chris:    So, what does this mean for food production today, you know? I mean, that’s what inspired me by that photograph at the end of The Serengeti Rules documentary. On the one side, you've got the bison in this diverse ecosystem. And on the right hand side, you see a monoculture of some grass-based crop with a giant combine harvester in it. Clearly not a diverse ecosystem. It’s a monoculture of one plant and the nutrients are not being put back into the soil by some ungulate that’s been moving along by the fear of some other predator. It's completely artificial. Does this have implications for the sustainability of growing plants in this manner? 

Jim:    Oh yeah. I mean, it certainly has implications. Exactly what those implications are is— 

Chris:    We just don’t know.

Jim:    Well, we know some things, but I think that the implications— There are dimensions to those implications that we don't understand very well yet. I think it raises a question of, you know, as far as meat production. What we have done in North America is that we've taken out all the predators and we've taken out the large native herbivores. Remove the bison, remove the big predators that were feeding on bison and that were feeding on the surrogates that we have put back in that system as domesticated herbivores. Those are cattle and sheep primarily. It raises the question of whether both economically and nutritionally people and the system would be better off if we just let it go back to a bison-driven system. Now, if you had bison in the system instead of cattle— This is just a thought. I don’t know if it’s true. It’s just a thought. Bison did fine when wolves were running around unregulated in North America. They are big and they aren't as vulnerable. You wouldn’t have to worry about wolf control anymore at least so far as bison are concerned. So, what if you just took a view where instead of having a cattle-based production system, we're gonna let the system return to a bison-based system? Take down all the fences, create some sort of a different economic infrastructure, and ask the question would the landowners actually be better off. Could they make more money harvesting bison than they are currently making by harvesting cattle? I don't know the answer to that question, but I think it's an interesting question. 

Chris:    Uh-huh. I think it's a very interesting question indeed. And I also wonder about— You know, we talked a lot on this podcast before about the gut microbiome and that is also an ecosystem. Right? Would you expect there to be keystone species and trophic cascades in the gut microbiota? 

Jim:    I don't know enough about digestive physiology to answer that question. I mean, it's easy to say yes, but I mean it would be— My opinion on that is no better and perhaps worse than any number of other people.

Chris:    Right.

Jim:    So, I don’t know. 

Chris:    Can you give us examples of other ecosystems whether the rules have also applied? 

Jim:    I'm thinking about nature mostly from the perspective of large predators. And we have seen these impacts that are more or less in keeping with the influence of a predator, an herbivore, and a plant pretty much across the world now. So, we’ve seen them with large predators in North America. Wolf is the icon, but it isn’t really just the wolf. It’s wolves, and pumas, and bears. Wolves are obviously an important element of that component to the system. So, we’ve seen that in North America. There's evidence for the same process in Europe and across Asia in wolf, bear dominated systems. There's evidence for the same processes in South America now with the interaction between puma and vicuna in Argentina and in the grasslands of Southern South America. 


    There is evidence for the same sorts of processes in Australia with dingoes being the surrogate that are there now as the predators in the system.

Chris:    And I know that the dingo is a feral dog. Right? It was once domesticated.

Jim:    Yeah. It’s a feral dog. It's a replacement for the native Australian predatory wolf. So, there was a marsupial wolf that is now extinct. 

Chris:    Wow. 

Jim:    And the dingoes who essentially run all over Australia now, they are kind of quasi-natural. They were introduced, but they've been out there for a long time. And they are wild populations of animals all around. And so, they have a big impact on herbivores in that system and in a lot of other things. Now, there's evidence and I've just finished reading a very interesting dissertation from Tasmania on Tasmanian devils. 

Chris:    Oh, yeah.

Jim:    And so, there's some pretty good evidence that Tasmanian devils were a very important element of that part of the southern hemisphere ecosystem as well. So, pretty much wherever people have been able to look, they have found the same sorts of rule.

Chris:    Right. What about here in Santa Cruz with the— We don't really use the word “puma” here, do we? Is that technically correct? We say mountain lions.

Jim:    Mountain lions, pumas. Yeah. Yeah. There's actually been a big study that's been going on. It's primarily led by Chris Wilmers who’s in the environmental studies department here who’s, you know, kind of a midcareer ecologist now. He's coming in and he has worked— Mostly Chris’ lab in conjunction with Terry Williams who is here in ecology and evolutionary biology. Terry has done more the physiological part of it. Chris has done more of the data management, and ecology, and field part of it, but they've been working on pumas, puma-deer interactions, ecology of fear, the impact of pumas on deer, on plants in the Santa Cruz mountains. And for the most part, they've been seeing things that fall very much in line with this general model. 

Chris:    That’s phenomenal. I think that's a good place to wrap up. Where can people find out more about your works? So, we’ve been talking about the book, Serendipity and Serengeti Rules, and there’s a documentary of the same name. It’s on PBS Nature and the BBC iPlayer. And it’s one of those phenomenal pieces of work that works at multiple levels. My 6-year-old daughter asked to see it again the moment it finished. And I think she's appreciating it on one level and then I'm looking at it and seeing it on another level. And I think some of the best content in the world is like that. I'm sure you can think of the Simpsons or— I’ve watched the movie Zootopia recently. It was very much like that working on multiple different levels. What else would you recommend for people to find out more about ecology and your work? 

Jim:    You know, I think those are the primary sources. My book for my own work, it is a source I would recommend. It has links. I think it's readable for it was written not for professionals necessarily, but for the general public. There is some bits of it that are fairly technical, but I think anybody could pick it up and read it and understand it without too much trouble. A little video clip that— 

Chris:    Oh, the 20-minute video. I forgot about that. There’s a 20-minute version of the documentary that's available on YouTube.

Jim:    Right. Howard Hughes again. Howard Hughes Medical Institute. That can be Googled and found, downloaded, and watched. It’s 17 minutes long. I think it was intended as an educational video for junior high, high school, and beginning college students. And it's been downloaded a lot and it’s used a lot for that purpose. And now, anybody that want it or sitting there at their computer that has access to the internet can download it for nothing and watch it. And I think it's a very clear, well put together little snippet on these ideas. The longer film, The Serengeti Rules, available in several different forms. There’s a theater, the longer form. There's the television form, the PBS and BBC form. It's been shortened to fit into an hour— 

Chris:    I didn't realize that. So, I’m gonna go and find the longer version now ‘cause I’m obviously interested. 

Jim:    So, the longer version is a little different, but the underpinnings are the same. There’s a lot of overlap. There’s a lot of similarity in the material in those two. Those are the main sources that I would urge people to see. You know, The Serengeti Rules, the movie in particular, it's just fun to watch. 

Chris:    Oh yeah.

Jim:    You know, the videography is beautiful. The music is great. The people who put this together were professionals. The film was put together by a documentary film company in London called Passion Pictures. And they were superb. I’m just in awe of how good they were. 

Chris:    Yeah. I’m often in awe of the wildlife photographers. Sometimes you get some insight. We subscribe to this channel called Curiosity Stream and you find a lot of content on there. I guess it's the same filmmakers that make the content that ends up in the big BBC nature documentaries. 


    They get narrated by David Attenborough, but it's like all the stuff that got left on the cutting room floor. And they quite often narrate the content themselves and you realize that, wow, this guy spent 3 weeks, sat in a hide with a huge lens as long as my arm to get, you know, a few seconds of content that went into one of these documentaries. And the patience and grit of these people is quite extraordinary. 

Jim:    Well, The Serengeti Rules is a little different in that it's built a lot around the interview with the principles and that's what makes it unique. The scientists that actually did this work are talked to and they explain their lives and they explain how the work was done. And in the process of explaining how the work was done, there are pictures and film segments that demonstrate the process. I can't imagine anything that would be more digestible— 

Chris:    No.

Jim:    …and pleasant to watch really.

Chris:    Yeah. Absolutely. Absolutely. 

Jim:    I would urge people to see the film.

Chris:    Definitely. I would join in that. Well, Jim, this has been fantastic. Thank you so much your time. 

Jim:    Yeah. My pleasure. 

Chris:    I very much appreciate you. 

Jim:    I’m happy to do it. Yeah.

Chris:    Thank you. 

Jim:    Glad to. Sure. 

[1:01:08]    End of Audio

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