ANDRE DHONDT: Good evening. It's my privilege tonight to introduce Andy Dobson, professor from Princeton, who is on his first visit of hopefully several as an A.D. White Professor-at-large at Cornell. My name is Andre Dhondt. I'm a professor in the in the Department of Ecology and Evolutionary Biology. And together with Krysten Schuler, we co-host Andy, she for the part in the vet school, me for the rest of campus.
One of the things you have to do when you nominate somebody for a Professor-at-large A.D. White professorship is to explain that the guy is absolutely phenomenal. Now, with Andy that's not the problem. But you also have to convince your colleagues that the broader Cornell community would be interested in his visit. So to do that, you ask your colleagues to write letters, and you put all the letters together, and you then send them to Penny, the A.D. White Professor administrator. And the committee decides, and in the case of Andy actually, I think turned out to be quite easy. He was unanimously nominated, and then the Board of Trustees appointed him. And it's a six-year appointment, so he'll come back probably another two times, I hope.
Now, rather than enumerate all his multiple achievements, like more than 30 papers in Nature and Science, an h-index of 82, things like that. Let's not worry about that. Let's just-- I just want to read you a couple of sentences from-- nomination from the support letters that I received when we nominated Andy. One colleague said, he's a superb scientist, an outstanding teacher, and one of the most dynamic members of the large academic community I've ever known. The breadth of his research is outstanding, and almost without parallel in the ecological community. This clearly points to his unquestionable potential to have large collateral benefits for the Cornell academic community should he be given the opportunity to serve as an A.D. White professor.
I was very happy that this colleague underlined the fact that he is a dynamic person, because one of the questions you have to answer when you nominate somebody is, will the guy be physically up to it? So I said, yes.
Another letter said, he's without question the single best person I can think of for this honor. A very distinguished scholar who powerfully crosses fields that offer great excitement and potential for scientists here at Cornell. From modeling to disease ecology, to parasite biology, to conservation. And all that, and he's a great communicator.
So ladies and gentlemen, I give you Andy Dobson, a longtime friend, an outstanding scientist, and a great communicator. Andy.
ANDY DOBSON: Thank you.
Thank you very much Andre, for that very kind introduction. And my apologies to all those people who had to perjure themselves writing that letter.
It's a great honor to be here. Cornell has always been a very special place for me. I've visited often over the last 25 years. And I've found every visit stimulating. This week has been absolutely superb. I have talked to so many brilliant and exciting people that I'm not really sure I'm physically up to be able to give this lecture. But I hope to get through it.
What I'm going to talk about is sort of different from my sort of other part of me that works on diseases. I'm going to talk about stuff that I've been doing with friends, and in the background, because I felt it was important to do. It's still science. I hope it's got, it's got chunky bits of science in it. But it's something to just do because I felt it was important to do it.
It's been done with, predominantly, two absolutely amazing women scientists, Joyce Poole, who I met when we were both postdocs together back in the 1980s I guess that was, and with Katarzyna Nowak, who has been a postdoc with me over the last few years.
We're going to talk about these animals, much bigger than the parasites I usually work on. Am I--
- Just gonna make a slight adjustment to your mic, so you sound a lot better and crisper to everybody.
ANDY DOBSON: Okay.
ANDY DOBSON: Am I better and crisper? OK, cool. Crisper is not that thing we were talking about. Don't any of the microbiologists get excited. We're not going to talk about CRISPR.
This is a beautiful male elephant who's named Little Male. He was little when he was born, about 44 years ago. This picture taken about earlier this summer. He is in his prime. He is 44 years old. He's beginning to be able to get matings. He is ready to make major contributions to the future of the elephants of Amboseli, where he's lived since he was born.
He was shot two weeks ago. He had gone out of the park, raided the crops of a farmer, the farmer had come out to protect his crops, the farmer wasn't as big as the elephant, the elephant turned round, swiped him with his trunk, killed the farmer. The Kenya Wildlife Service people felt this elephant is now a man-killer, we should go in and kill him. So they just went straight in, shot him, didn't collect the ivory or anything, just left the body there.
And that instantly sort of epitomizes the sort of moral dilemmas we face when we look at elephants. And the people who've been looking at them, I've been looking at it for last 25 years, how do we do this calculus of what's the value of an elephant life versus the tusks that are attached to it, versus the human lives or the land to grow crops on? And that's going to be the underlying theme of much of what I talk about today. So tragically, Little Male will no longer play much of a future.
So I'm going to divide the talk into three sections. Initially, I'm going to talk about work that's largely stuff that I collaborated with, but they did most of the work, on the demography and social organization of African elephants. And that was part of a long-term study set up by Cynthia Moss and Joyce Poole at Amboseli, with Cynthia focusing on the females, Joyce focusing on the males, and then Phyllis Lee, Keith Lindsay, and then more recently, many, many Kenyan students working with them to understand these elephants. Partly because if we're to look at the interaction between elephants and the ivory trade, the second part of the talk, we need to understand how elephant populations work. And they work in very complex and beautiful ways.
So I'll then talk a history of the ivory trade over the last 200 years, condensed down to about two minutes, and then talking about what we understand of the interaction between the ivory trade and elephants, and what's the future for that over the next 20 years.
Finally, I'll go in a slightly overlapping direction to talk about the international body that overlooks trade in elephants, and in fact trade and all species, CITES, and ask how good a job does CITES do with elephants, and how good a job in general does it do with the trade? And then, a curious thing, how much do elephants actually interfere with the way that CITES works? And that's all work I've been doing very recently with Kate, Katarzyna.
OK, this is the initial cast of characters, people have been working at Amboseli or with Kenya Wildlife Service. Joyce is in the front there, Cynthia, Ian Douglas Hamilton, Richard Leakey, Soyla, Katie, a wonderful bunch of people.
Richard, when he took over Kenya Wildlife Service, did something that many people thought was extraordinary. It was on the post I noticed you used for the lecture. He collected all the ivory that had been confiscated from poachers, put it in Nairobi National Park, and set fire to it. And the economists said, you must be mad. You've just burnt at least $5 million, in 1988 dollars, that could have been sold and used for conservation. And Richard said it was worse doing this, because it would stop-- it would make the message that we would rather burn this than have people kill our elephants.
Now, what was the logic behind that? Well let's go, first of all, to this wonderful place, Amboseli, in the shadow, or the reflected shadow, of Mount Kilimanjaro. The elephants there have been studied since 1972, by Cynthia and then Joyce starting in 1974. They know every individual in the population.
So you can look at the numbers, follow everybody's history through time. The population has steadily been increasing because it's relatively well-protected from poaching. There's variation in that increase. Some years it grows quite quickly, some years it goes more slowly. So there's variation in the annual rate of increase, but on the average it's growing at about 2% a year.
As I say, every elephant is known as an individual. You can do that from the shapes of their ears. The various tears give them away. The shape of their tusks, whether their tusks are broken. Even the sort of circles around their eyes, once you get your eye in, allow you to identify them as individuals. So everybody's known, and you can follow them through time.
You can age them when they die by looking at their teeth. Unlike you or I, elephants have five sets of teeth that come through the jaws, the different little bits that-- the little plates fission to give these huge teeth that gradually wear away as they eat woody and grassy vegetation. So ultimately, life expectation in elephants is determined when their last set of teeth fall out. Once you've got no teeth to chew anything with, you eventually just chew your jaw away and drop dead. A small proportion of elephants ever reach that age.
Now the other vital thing, and many of these slides have been customized at great expense to the era when I actually first drew them, the one thing that defined elephants is their tusks. Obviously we wouldn't have an ivory trade if elephants didn't have tusks. Tusks grow at a different rate in males and female elephants. Female tusks grow slower, and settle down at a sort of average size of about 10-- 8 to 12 kilograms. Male tusks just keep growing and growing and growing and growing, as I've shown you the biggest set of tusks ever taken. This graph goes up to 50, but they can be easily two or three times that, 50 kilograms.
You can also plot, on that graph, the age of sexual maturity, which again is very different for male and female elephants. Females can become sexually mature at about 8 to 10. They usually have their first calf at about 10. Males don't really become reproductively active until 20. As I'll show you, it takes much, much longer than that before you're an acceptable male to mate with any female.
So we can look at elephants, the other thing about them, is you can age the ones you can't get the teeth on by looking at the height at the shoulders. Now, you can rush out with poles and try and measure them, but you'd end up like that guy who went down to protect his crops. So what Phyllis Lee worked out is you could take photographs of elephants, wait until they've gone away, and then rush out and take a photograph of a pole, superimpose the picture of the elephant on the picture of the pole, and then you can measure its height at shoulder height. You could also measure the size of its footprints, look at those, and get very accurate estimates of age.
You can also show that elephants die relatively slowly. The survival curves, the females actually survive better than males, once that testosterone starts kicking in. As with humans, it increases the mortality rate of the males much more than the females.
Age at first reproduction, as I say, 10 to 12, but some females may not start reproducing until they get to 20. Inter-birth interval is about four years. If you lose your calf when it's little, you can breed a little bit earlier, but it's not exactly four years. If conditions are not right, it can take much, much longer. And females continue reproducing right through their life. This is age-specific. Fecundity against age for females, it goes up, peaking at about age 12, and then stays roughly constant until you're well into your late 50s and early 60s.
This thing sets up the social system for elephants, because elephants live in this amazing matriarchal society. If you're a female elephant, you live with the same females you were born with for the rest of your life. This is a female with her most recent calf standing behind her. The one that's four years older than that standing beside her; the one that's four years older than that standing beside there. They're all females. The one at the back is her sister, with her calves of several ages. So you live in this hugely structured society of females that kick the males out once they get to about a bit obstreperous, starting being sexually active. They kick them out at about age 15, 16, and they go off and live in little male groups by themselves.
So a female's life is essentially you have a high, a lowest probability to be about 10. You have a sort of increasing survival of probability and starting having calves between 10 and 20. You then have a very good chance of surviving through until you're 50. And then you get older and your mortality rate begins to increase a little, and your probability of having calves declines a little. As I say, we can age them.
Males are different. This is a completely different beast. This is a huge animal. This is an elephant appropriately called Beach Ball. He is about two to three times the size of those females. Huge tusks. He spends a lot of time being solitary, but once in a while he gets together with other elephants in a social system that reminds me of Glasgow on a Saturday night when I grew up.
Essentially, whenever male elephants find other male elephants, they want to go and beat the pulp out of each other. And they will only fight an elephant that's roughly the same size as himself. If an elephant's much smaller, he knows he's going to lose the fight, and runs away. So the older you get as an elephant, the bigger you get, the better chance you have of winning fights. And the prize for winning the fights is, of course, matings with females.
If you look at male reproductive success against age, and this is a sort of curious thing, there's this word at the bottom, musth. Male elephants go into a thing that's the male equivalent of estrus, a period of heightened reproductive activity when they're very, very attractive to females. They will leave a sort of trail of green slime behind them. Any female who smells that green slime will turn and follow it until she can find that male if she's in estrus.
And there are advantages. As you get older and older, your number of females you can mate with can be up in the several hundreds a year. So the prizes getting old and winning all those fights are huge for that period of time that you are the biggest and meanest elephant on the block.
And indeed you can see that in this slightly more confusing slide. These days of the year on the x-axis, wonderful work that Joyce put together. Age of elephants, the oldest males in musth, this period of heightened activity, at the time of year when most females are in estrus. All the younger males don't get into musth then. They're sort of essentially suppressed out of it by those older males. So those old males get most of the mating. And indeed what happens if a female finds a male in musth, she will go and mate with him. She then makes a call that elephants don't make at any other time. And this excites all the other females to come over and find out what's happening. And they will then hang around with that female until he's guarded her for two days. They will then be in estrus and ready to mate with him. So that's a beautifully complicated mating system.
It also creates a huge reproductive skew. It means the maximum number of calves that a female can produce over the duration of her lifetime is about eight, one every four years or so. A male, over 20 years, can easily sire 50 to 100. 50 is the maximum recorded, but you're not seeing all of the matings. And as we begin to do the genetics, we realize that some males have been having many, many more than that.
There's also a second curious effect, that there's this interaction between rainfall and female fecundity. Africa is famous for having years of droughts, years of rain. This is what the rainfall looks like at Amboseli, some really good years, some bad years. This is the proportion of females giving birth. And plainly you can only give birth when you're not carrying a calf around. If we superimpose those two graphs, years when it's been, two years earlier, lots of rain, is when lots of females conceive and lots of calves are born.
Those calves are all living in a group with their mothers, their sisters, their grandmothers, and they're all mated by the same male, which is a curious mating system, that you and your mother can have offspring by the same male, who won't then live long enough for the offspring he sired with you to be around when he's died. So there's no inbreeding, but you have this curious thing that you're hugely related to the females you live with, and you're also related by sharing the same male genes.
And that's, I think, curious. Because if you play around with the math of that, it creates a sort of stochastic haplodiploidy, something that's similar to the mating systems we see in the social insects. You are extra-related with the elephants you're actually living in the same group with. And does that contribute to making elephants super-social? We don't know yet, fully. But I find that quite an extraordinary result.
So why did Leakey like that bonfire? Having given you that background on elephant social systems, I'll disrobe mildly and move-- the bonfire's a bit warm up here, so I will-- it's okay. To get to that answer, you have partly, he went because he spent time at Amboseli. Joyce and Cynthia were explaining the social system to him. This is someone from a family of people who were originally famous for looking at early human origins. He said, this is extraordinary. I mean, what does this tell us about how human societies evolved on the savannas, the switch from a matriarchal society to a patriarchal society.
If you look back at wonderful work by E.J. Milner-Gulland, John Beddington, and Bob May, they tried to reconstruct the history of trends in ivory sales back to 1810. Before that, ivory was mainly carved in India. Africa didn't really open up for ivory until the end of the sort of 18th century, about 1810s. The ivory that was carved was usually one tusk carved by several generations of a family, and then passed on to whoever the ruling person was in that part of India where they lived.
Once we get to the 1810s, two things happened that massively increase the demand for ivory. One is billiards, and a demand for billiard balls. And elephant ivory is just the right texture for billiard balls. You can carve it into circles and have perfectly hard balls that don't shatter when they bash into each other. The other tragic thing is we have to lay the blame at Mr. Beethoven and Mr. Schubert for having pianos that were built with a steel frame, and much cheaper to build than the wooden ones where you needed such high-quality wood that they can't warp. Once you've got steel-framed pianos, there's a huge demand for ivory for the keys. Because when you play a piano with ivory, the sweat from your fingers is absorbed by the ivory rather than getting all slidy if you're playing a sort of plastic key piano.
So you see this steady increase in demand for ivory, which continues through into the 20th century. Indeed, if we look at what was going on in Kenya, the volume of ivory through the 20th century is relatively constant, superbly driven by the price of ivory. Suddenly, when we get to the 1960s, when we go off the Bretton Woods agreement, go off the gold standard, all sorts of other things start driving the commodities market, ivory becomes a much more important commodity, the price jumps up, and that hugely increases the demand for ivory.
You can actually look, again this wonderful thing that E.J. And John Beddington did, at how has that demand for ivory affected the growth rate of elephant populations. And you can show that elephants have been steadily declining since about 1810. Now, I worry that everything we've seen this century has had a huge impact on elephants. That's certainly true. As I'll show you, it's probably reduced them by at least 50-60%. From 1810 until about 1970, they reduced by about 90-95%. So before the present crisis began, we probably already lost 90% of the elephants we had two years ago.
And this is a classic graph. This one a real wonderful vintage. This is what was going on in ivory in the 1970s, right up until Joyce and Cynthia had that conversation with Richard. Global sales of ivory are going through the roof. The numbers are actually beginning to crash down, which is a classic example of an over-exploited population that's about to collapse. Any fisheries biologist would look at that and say, that population is in deep trouble. You're running out of stocks of elephant.
So that's when Richard said, it's time to stop this all happening. Let's light this bonfire. And indeed it reflected a poaching wave of professional poachers who'd been spreading across Africa. We went and dug out all the data from this from various sources. But starting around 1979, each dot represents ivory from the country in which those dots are placed. You can see through time, 1979, 1980, '81, '82, a wave spreading down through Africa that eventually, when that bonfire is set in 1988, stops.
And that tells you two things. Most of the poaching was very organized professional gangs getting the ivory out and taking it to markets. It also says that all of the talk from South Africa and Botswana and the southern African nations about being super-efficient at stopping poaching is complete nonsense. The professional gangs of poachers never got there. And they still haven't really got there. At the moment, they're focusing on rhinos because they're even more valuable than elephants. Southern Africa has not yet experienced a major ivory crisis, as I'll show you.
So let's go back to this. How does the poaching work, and what does that natural history we learned about elephants tell us about how poaching might work? Because if you're a poacher, do you just go and shoot any elephant? Or, if you want to sell the ivory, you should go for the ones with the biggest tusks. And how's that going to affect the social structure of elephants?
Well let's look at that. These are the largest tusks ever taken. These used to be at the entrance way to the Mweka Wildlife College in Moshi, in Tanzania. They're much taller than this guy, and this is quite a tall guy. They weigh 120 kilograms. This was a massive elephant, shot on the slopes of Mount Kilimanjaro by a professional hunter in about 1918. Massive tusks.
If you look-- and this is work that Joyce put together that got me involved in the first place --if you look at the average size of tusks entering the trade in the '70s and '80s, the average size goes from 10 and drops down to four kilograms. Those are not huge elephant tusks that are being taken. And indeed, if you look at that in terms of that graph-- as I said the biggest tusks would be way, way up here, the ones that are really valuable --by the time we go into the '80s, the average tusk size is down here. And that's representing either very, very young males, perhaps too young to even be sexually active yet, or females who are in their prime reproductive time.
You can look at some of the geographical patterns in that. These are just data for about 1988-89 of ivory officially recorded as leaving different African countries. And you can see the southern nations, the poaching hasn't arrived. The tusks being taken there are significantly larger from those from the eastern and central African countries, which are down at this four kilogram ones. The average size of stuff going into the market in Singapore is about 4-5 kilograms.
The most miraculous ones are these ivory coming out of Burundi. Burundi at this time was legally exporting 2,000-5,000 tusks a year, which by some genetic was all produced by five elephants. And none of their elephants ever died, even though they were exporting thousands of tusks a year. And that gives you an index of just how corrupt the ivory market was. It was possible for this country to have legal certificates to say it could easily remove several thousand tusks from five elephants every year. Totally bonkers.
Now, let's bring out our inner nerd and make some models of the elephant populations. Just a simple harvesting model. We'll just assume we haven't got two sexes to begin with. One sex, we'll assume that it's Amboseli, it's settled down as female elephants at Amboseli. We'll harvest a random 2% of elephants per year. When we do that, the elephant population declines. Ultimately, 2% would hold it at a relatively low abundance. So supposedly that would be a sustainable harvest. If we stop harvesting it, it recovers. But it takes of the order of 100 years to recover. It doesn't instantly bounce back.
Secondly, notice that as you harvest it at a constant 2% effort, the yield of ivory decreases. Because you have half the size of the elephants, you end up with half the ivory yield. Is that relatively straightforward? Good, if you've got that, you're ahead of most of the economists who work on ivory and elephants. They think if you harvest at a constant rate, you end up with the same number of elephants through time. And so economists, as you will have realized now, do not do population regulation. They just think everything keeps going all the time, so you can harvest things at a much higher rate and they won't decline in abundance. So we're making progress.
You could take this relationship between how far do we decrease the size of the population versus the yield, and plot it out as if you were a fisheries biologist, which is a slightly more complicated way of looking at things. But this essentially says, if you don't harvest the population it will settle down to something you might call a carrying capacity. As we harvested at a quarter percent a year, half a percent year, 1% a year, we will reduce the size of the population. So it will be a sustainable level, but it will be reduced by half. And we will have our maximum yield of ivory if we're taking about 1% a year. As we go up 2%, 3%, we'll eventually eradicate the population, and they'll go extinct. But as you get higher and higher take, you get less and yes yield, because you've got less elephants to take that higher yield from. So we're now well ahead of the economists.
You could use that to say how quickly will the population decline. If this is your percentage annual removal, how long will it take you to drive them extinct? If you take 10%, it'll take you-- 10% a year, it'll take you about 80 years to drive them extinct. If you take 5%, it will-- they may not go extinct, they'll just go to a very low abundances. The black line is how long it takes you to half the size of the population. So the bigger the exploitation level, the quicker it goes down.
And what Richard said, well, Leakey said, can you get me the estimates of what the harvesting, what the poaching rate is inside Kenya's parks. And the rate inside Kenya's parks was about 18% in the '80s. And he said, we won't have elephants in 40 years if we let this continue. And that again said, let's light that bonfire and stop this happening.
And that's a dumb way to harvest them at random. Because if you're a poacher, you're much better off going for the ones with the biggest tusks. So what's the relationship? What if we were to say that poaches were super-smart, ahead of the economists, and took elephants with the biggest tusks. Well, we could plot out a graph that says, here's the age of elephants, here's the average tusk weight, what happens if we only let tusks of a certain size into the trade? Say, bigger than 50 kilograms, bigger than 40 kilograms, bigger than 20, down to our four kilograms. Notice if we're at four to five kilograms, we're taking very young males and mainly quite young females.
If we do that, our relationship between stock size and yield size changes. We now have this really crappy looking graph, which actually really does have two bumps. This is when we're taking males. This is where we switch to taking females, but mainly older larger females. So we have many, many more elephants. We don't have many males. But we've got lots of females, and we hope those males who are left are able to mate with those. So we get a completely different yield of ivory if we only let tusks into the trade that are bigger than about seven to 10 kilograms. But we were down to four kilograms, so we've got many less elephants, and we're also getting many more yield.
And indeed if we compare the two curves, and here I've changed the axis so you can actually see it really is two bumps, so this is 90% of population size, 99%, 9%, the most important thing from this figure is if you harvest elephants by taking the ones with the biggest tusks, you get 10 times the yield than as if you harvest them at random. And that again puts into play the pure nonsense that we hear coming out of the southern African countries, because they say, we need to harvest our elephants to get money to pay for conservation. So we're going to harvest them at random. If you harvest them at random to get money to pay for conservation, you're losing 90% of the money you could get if you just waited for them to die, and pick the ivory up off the ground. So again, pure nonsense from relatively weak science.
Now what happens to the populations? If the poachers are being efficient and harvesting males more than females, As the relative population declines, what happens to the sex ratio? Well obviously, take more males away from females, the ratio of females-- males to females, will get larger and larger. You've got less and less, you've got more and more females per male. This is on a log scale. So this is 10 females per male, this is 100 females a male.
What do we see if we go and look at elephant populations? Well one thing Joyce did was to go to different parks in a Land Rover, occasionally breaking down. Using Amboseli, an un-poached population, as a control, you have about 3/4 of the adult population is female, about a quarter is males, though very few of these would be old enough to reproduce yet. If we start going to other parks in east Africa, sorry, Kenya, Tanzania, Uganda, the proportion of males to females is often up to 100 to 200 per one. That is a deeply distorted sex ratio.
And so you have these massively distortions in the numbers of females to males. What does that do for the population? Well again, you can make models of this, where you have a sort of predator-prey. And that's a Freudian way, males searching for females, females-- in a population of females living in groups of different sizes, the bigger the groups of the females, the more isolated they are, and the harder it is for the males to find them. It's great when they do find them, but essentially as this begins to happen, it's harder and harder for the males to find the females, and you'll stop getting reproduction in the females, because there'll never be enough males to be able to find them and mate with them.
Again, you can show that-- how that works in terms of the sex ratio. The bigger the sex ratio and the more the females are aggregated into group, the less chances that any of them get mated.
And that would be a classic example of an Allee effect distorting the shape of elephant populations. You put that back into our model and say OK, we'll put that Allee effect in. Let's harvest the population, and then let's stop harvesting it. At a certain point, when you stop harvesting, it just collapses anyway. The females are not being found by males. There's not enough males to go around. The thing will collapse.
So that was a very good reason to try and stop the whole trade. And it was very effective from about 1988, '89. CITES put a ban on elephants. This drew attention to the ivory being worthless. People would rather burn it than wear it. And for about 10, 15 years, we had a period of respite. And then, just when you think oh, we've sold all this, this is really quite good news, there was suddenly an increase again in the poaching. Part of this may have been the slight recovery we've seen over that time period. But also a lot of it reflected changes in the market for ivory. And everybody said, this is because China has now got a much stronger economy, and they're able to start buying ivory. And indeed, we would see really gory things like this, elephants with their faces chopped off to get the ivory and the tusks, heading across to various locations around the world, whether it be carved into trinkets for tourists, or curiously, if you're in the Chinese military, if you give your commanding officer an ivory carving, you favor your chances of being promoted. So that's also another sort of dodgy use for ivory.
And again, we found ourselves back in another battle, fighting to-- how do we keep elephants going. Lots of work showed that ivory was indeed going across the Indian Ocean into Vietnam, through Singapore, Malaysia, into-- and then into China. But as I'll show you in a minute, that's an artifact of the way we were looking.
So, by this time, we had better data coming in into elephants, so Kate and I started looking at different ways of looking at this, and put together a database. There was a database that IUCN and people had been putting together for elephants, but we felt it was incomplete, and in a slightly paranoid way, they wouldn't let us look at it. It was like, OK, well we'll make our own database. We know where all the information is. So we made our own one, and we're happy to share it with anybody.
What that showed us, so anyway, is that there are many less elephants left in west Africa, increasingly less left in central Africa, still quite a lot then in east Africa, this is about sort of 2010, and many still in southern Africa. Everybody sort of sought to do that, to sort of try and say, well, how many African elephants are left, and could we do different ways of counting them? If we put together the data we were really confident with, people felt there were about 400,000 elephants for sure in Africa. Maybe there was another 82,000, and maybe as many as another 200,000 to get us up to of the order of 3/4 of a million, or 2/3 of a million. We were kind of skeptical about that.
And so we really wanted to look at our database and sort of say, well, can we put together a database, look at all the hundred-odd places where people have been studying and counting elephants, and then fit some sort of model across Africa, fitting it to each individual population, dividing them into forest elephants and savanna elephants, which are different species, estimate the sort of simple parameters of a simple model, and then do two things: one, try and look at the rate at which different populations were being poached, which would give us an indication of how many tusks were being removed, get information on the tusks entering the trade, which would then, the ratio of those two things would give you an indication of what proportion of the ivory that's being poached is actually located and confiscated; and what's the long term impact of that going to be on elephants?
So one of the most useful pieces of information we got is collected by the African Elephant Research Group. They spend a lot of time going around looking for dead elephants, and classify elephants as either having died naturally or having been poached. So they produce an index that's called the PIKE index. And it's deeply confusing, because the organization monitoring it is called MIKE, and they produce a statistic called a PIKE. But PIKE-- MIKE collects data on illegally-killed elephants. Monitoring illegally killed elephants is MIKE. PIKE is the proportion of illegally-killed elephants, so it's essentially poached elephants divided by poached elephants and natural mortality.
Now, these PIKE numbers seem to be increasing through time, which is worrying. More and more illegally-killed elephants were being located. I find it frustrating to use an index like PIKE, so it was like, well, let's do the simple algebra and convert the PIKE into a proportion of elephants harvested, which is a simple exercise, algebraically. Because then I can relate that back to all the calculations I've done before of, how does the population respond to different percentage harvesting rates.
So I can convert a PIKE into an h, a harvesting index. I can also quite simply take data for different African populations, look at the PIKE index, and then look at the change in the size, the change in the growth rate. So this is the growth rate, not the population size. Once the PIKE gets above about 50%, the population will decline. If it's above 50%-- below 50%, the population will potentially keep growing. And if we do that, dividing all the sites into ones from west Africa, central Africa, east Africa, and southern Africa, the declining ones are very much west and central Africa, the ones initially are in east and southern Africa.
Now, the curious thing is that the MIKE people think the PIKE represents harvesting level. And they believe that the sustainable harvest level should be of the order of 6%. Now I showed you earlier that if you get above 3%, you will drive elephants extinct. And that's because they've talked to economists and forgotten about including the way the populations are regulated. So they feel that anything below 5% is sustainable. It is sustainable, but it will reduce the population to 1% of what it would be if you didn't harvest it. So again, they're deeply confused about this. So they think above 5%, population increases. It will increase, but very, very slowly. If you go back to my figure, those 3% and 4% bring it down to a very, very low level. Stop harvesting that level, it'll bounce back. But you are over-exploiting it if you believe this curve.
So what did we do? We then collated all the data that they wouldn't let us have, but we found ways of getting it, for all these different sites, and then fitted a model to it to try and get at these other figures. So we can take a really simple model that just says, the number of elephants next year will be the growth rate of the elephant populations minus the proportion harvested. And the proportion harvested will be given to us by the PIKE numbers. We will look at PIKE numbers for wherever we've got them. And then we'll average them locally, and produce a sort of, what's our best estimate of the PIKE rate here if we've got data for two sites within 100 kilometers on that? And we'll do that across Africa for most of the first 15 years of the-- the first 12 years of this century. That gives you quite an accurate fit, the best fit. It has a sort of background mortality rate of about 95%, which would tie in with Amboseli at a population growth rate of about 1.06, which would tie in with Amboseli.
Now this looks messy, but it essentially says-- it's color-coded --the big populations, this is population size, are all in southern, and at this time, east Africa, they're not declining very rapidly, though we're beginning to see some declines. West Africa has small populations, and they're gradually all dying out. And indeed, if you aggregate those together, this is the estimated numbers of tusks removed.
So blue is central Africa. They're mainly forest elephants. From about 2001 through to 2010, we see, and this is sort of aggregate, this is each year, of the order of 20,000 tusks removed in some places. Black is east Africa, this huge increase of poaching you've heard about as it moves into Kenya and Tanzania. Red is southern Africa, beginning to take off there. Green is West Africa. It's not particularly large, because there's no elephants left.
And if you then convert that into the amount of ivory seized overall, it suggests that on average, despite intensive anti-poaching efforts, we're only capturing about 5% of the ivory that's actually poached, a pathetically small amount for huge amounts of money spent. Again, you can show by region the accumulative amount of ivory. East Africa was getting more and more taken off, central Africa, huge amounts. It's only beginning to increase in east and in southern Africa. There's almost nothing left in west Africa.
You could then say, well, what's the relative population sizes through time? Just, we know they're all different, but we'll assume they all start at 1,000, just to indicate. The southern African populations continue to grow, because they're being poached at a relatively low rate. The east African ones were growing and are now beginning to decline. The central African one-- the west African ones had hardly any growth and are in deep dive. And the forest elephants are also beginning to decline rapidly.
That's deeply worrying. We could say, well, what's that going to-- how do we stop that? We can light some more fires. And indeed, you can go to New York, you can go to Washington, you can go to big cities and see ivory being crunched up to try and stop it. They burn ivory every year in Nairobi National Park now.
But we can look forward and say, let's take that model, because we know it provides a pretty good fit to the data. We know the most-- the thing it's most sensitive to is that PIKE, the proportion of elephants illegally killed. Let's have four different scenarios, and look out from the time of the CITEs meeting last year to 2025 and say, there's four different things you could do. You could have a total ivory ban that stopped all elephant hunting in its tracks, the ideal thing you'd like to do, that's the orange line. If you do that-- this is our estimate of total elephant numbers, which we think is no more than 400,000 --if you stop ivory, if you stop the ivory trade in its tracks, the elephants would recover slowly up to 2025. You might end up with many young elephants, with back up towards 500,000, 600,000 elephants. If you have business as usual, just taking for each point the PIKE value it's had, just set those as a set of random numbers and run them forward into the future. So the business as usual, elephants might have a vague chance of recovery. If you were to harvest at the maximum sustainable yield, obviously if it's sustainable, you'd end up with exactly the same elephants in the future as you have now. If there's an increase in the poaching, you begin to get a slow decline.
But the devil of that is in the details. Because we can split it up into different regions and say, business as usual, you're going to lose all the elephants that you have remaining in the central African forests. And in west Africa, you'll have a steady decline in the west. And it only increases, because business as usual is not a lot of poaching in southern Africa. If you have an increase in poaching everything declines, and even southern Africa begins to decline. Obviously, if you have a CITES ban, you get a recovery in east Africa. You get very little of indication of a recovery of the forest elephants and in the west. You get a steady increase in southern Africa. So the recovery you're seeing has a huge geographical signature. It will occur at different rates in different places. And, in many ways, it explains the tensions between the southern African countries, who feel they have too many elephants, and there should be a trade, and the east African and west African countries who say, this trade continues, we will not have elephants anymore.
So that puts the elephants in a really scary dilemma. How are we going to keep conserving them? One way would be to get revenue from them in tourism. If we go to Amboseli, we can calculate the cost of all the ivory on the elephants in Amboseli. You can calculate the tourist revenue from people coming to see the elephants in Amboseli. The tourism revenue for Amboseli every year is 10 times their value as ivory at the maximum ivory prices. So elephants for tourism, in some locations, can be a spectacular way to generate revenue. But it requires elephants that have worked with people and are relatively habituated. That's not going to work everywhere.
The other thing we have for regulating the trade is CITES, the Convention for International Trade in Endangered Species. And this is the organization that decides whether we should have a ban on the sale of ivory, ban on sale of tuna, ban on sale of pangolins, et cetera. It meets every three years, looks at data of species in the trade to decide what to do. And it does spend a huge amount of time, almost a quarter of its time, discussing elephants. And that massively divides the nations who go, particularly the southern African nations, and the African-- and the nations that trade in ivory from those who don't trade in the ivory. And that creates a tension that affects all the other decision that CITES made.
So we thought it would be interesting to look at the CITES data for elephants, even though we know it only represents of the order of 5% of the amount in trade for elephants. There's very good books that can introduce you to CITES. These are two of my favorites. But there's also, now, a CITES database online that you can go to and download data. It's kind of a clunky database. So it brought tears to my eyes quite a lot when I was working on it. But CITES, as I say, is this thing we have for monitoring trade.
So let's look at couple of things about CITES. These CITES imports into two nations, where we are now, the United States, and China. And they tell you that CITES is doing an interesting job in monitoring the trade. CITES was set up in 1976. It classifies species under four categories. If you're appendix one, there is no illegal trade in you. If you're appendix two, there is limited trade. And appendix three, there are beginning to be constraints on trade. Appendix three, essentially the constraints are determined where the country that the species is exported from, appendix two is both the import and export country that put the constraints on it, appendix 1 is absolutely no trade.
So you can see, as CITES was set up, trade of anything, all species into the US, goes up to about 10,000 transactions per year in appendix one and appendix two species, these are cumulatively added up, with about 1,000 trades a year in appendix three species. What's happening in China is a more steady increase. And this of course reflects the political and economic changes in China. There's a steady increase in trade that jumps up as China becomes a greater economic power. But evil China is importing 10% of endangered species compared to the US. And that's not a figure you see bandied around much. Part of that may reflect the relative efficiency of the Fish and Wildlife Agencies in the different places.
But this says to me, don't let's point the finger too heavily at China until we've seen what's going on in the US. And indeed, if we go to elephants, these elephants are imported into the US, these elephants imported into big bad China, this is-- and there's a switch, because elephants were originally on appendix two, when the ivory was burnt, they go onto appendix one. So there's no longer any elephants on appendix two until the southern African nations overturn that ban. But this is the amount of ivory and elephant products entering the US. This is the amount going into China. It's actually a fifth the amount going into the US. And that, that I find deeply disconcerting, that we all think China is the problem, when a huger part of the problem is at home. So one of the things Kate and I have been doing is working with a rather extraordinary group of women who formed an organization called Elephants D.C. to go state by state and call for a ban on ivory products for sale, particularly by antique dealers, in the different states of the US-- antique dealers and jewelers, because there's still a ton of ivory somehow finding its way into the US.
So that suggests there's plainly a lot of ivory also going west. It's easy to trace it going this way, but why are we missing out seeing so much of it going in the other direction? And that's a wonderful challenge for somebody to go and work on.
We were having a meeting, just around here, in Tanzania, in July, early in July, about the 4th of July. And I was talking to a really super guy, Dale, having a beer, talking about the Serengeti. And we were talking about ivory poaching. And I said, you know, I think there's a lot going into the US. And he said, yeah, we're beginning to look at that. But I'm-- this whole ivory poaching thing is still going on behind the scenes. That was the last time I saw him. He was assassinated on the way to the airport a week later. So these people are playing serious games.
As I'm so curious, I couldn't resist looking at other aspects of CITES. So I thought, well, let's take a nation that has a huge trade, that is distributing stuff internationally, and that's Singapore. And let's just look at the trade that CITES monitors going through Singapore. So these are data for birds, mammals, reptiles, plants, invertebrates, and fish. So this is all trade going through Singapore, just an example of one nation, but a major trading nation. When I looked at the actual names of these species, these are from all over the world. This gives you the magnitude of trade in wildlife. It's growing, except it's collapsing. That's the same as that elephant graph I showed you, of elephants being overexploited, except this is for whole communities of organisms. And indeed, when we split it up between birds, these are birds mainly from Southeast Asia but also from Africa and South America, this is a classic over-exploitation graph. Whole communities of birds are being overexploited for trade. Whole communities of mammals, plants, and this doesn't include any timber and forest products in CITES. They can't keep up with it. Reptiles, corals, massively over-exploited and increasingly the fish somehow look dodgy, but we have different sets of data for collecting fish.
That suggests to me that trade is absolutely destroying biodiversity. Everything we see in detail for elephants is happening broad brush for whole communities of species. And no one is paying attention to it. It's really scary. Well, we're beginning to pay attention to it. So you think, that's interesting, CITES should be doing more about that. My initial temptation was to say, CITES is deeply flawed. Why are they not doing more about this? When you talked to the people, they really knew a lot about what's going on. And then you realize, but there's only about 10 of them. How come there's so few people?
So it made me ask, well, how is CITES funded? It's the organization that deals with the trade in every other species on the planet. It doesn't deal in slavery, though it is connected with-- the wildlife trade is as connected to the slave trade as it is to trade in arms and drugs. Those things are all intimately coupled together. CITES is probably, along with Interpol, best geared to monitor that. What is the annual budget for CITES? It is $5 million dollars. We have people working on Wall Street who get cranky and pissy if their annual bonus is less than $5 million. Some of them have-- they might be trustees here or at Princeton. And that money will go to a good cause. But $5 million to monitor the global trade in all the non-voting species that supply ecosystem services to us all is, I find, deeply pathetic. The average cost for the nations that contribute is $25,000. That's the cost of a graduate student. It's deeply pathetic.
So we need to find ways of empowering CITES. That way they would have a better computer database that wouldn't drive me nuts. But it would give them significantly more power to monitor what is arguably at the center of most of the corrupt trade in the world.
OK, essentially this has occurred because the world in which we set up CITES in the 1970s doesn't exist anymore. It's a much more complicated international trading world, but nonetheless, CITES is massively underfunded, and we need to find ways of taxing the trade to put more money into CITES to monitor the trade. And we also, bizarrely, need to get CITES to spend less time talking about elephants, and having a set of relatively simple mathematical tools that will allow them to easily classify species on different appendices. And I'm not going to talk about that, because I've run out of time.
So what have I tried to tell you? I've told you that elephants are in a lot of trouble, that they're an amazing species. You know, I love working on birds, but I deeply love working on elephants. I've learned so much from working about elephants. That we exploit them is, I find, a deep tragedy, particularly as we exploit them for, essentially, little bits of jewelry and pathetic little statues. Those were wonderful when several generations carved one tusk into something for some leader in India, but when you're just cranking them out for tourists to take home and break on the plane, that's a real waste of a species.
To understand how that species responds to exploitation, we need to understand its biology, but we also need to put together these sort of databases, fit simple models to them, extrapolate, and look at what's happening, and how organized and disorganized the trade is to deal with that. And the scary thing is, once you start looking at the international database for elephants and how they enter trade, you discover that most things entering into trade are massively over-exploited And we have a relatively short time left before we can do anything about that. Otherwise, there's going to be nothing to trade. So on that cheerful note, I will leave you. Thank you so much.
I'll only take happy questions. Yes.
AUDIENCE: Well, I just came from a lecture on space and, you know, finding bodies in outer space, and billions of dollars that go into that or other things that we spend money on. And it seems very sad, very sad. But I want to ask you, now I lost my, sorry, train of thought. My concern is overpopulation of the planet. And not only are we poaching the animals, they don't Say, the space that they had before, to migrate, to find food, to-- we're basically putting them into these little reservations the way we've done other humans. And that's not sustainable for them, either. From other lectures and documentations that I see, you know, sometimes thinking that we just have a park isn't also a solution, because animals need to migrate. They need to do that to, you know, not just know animal, but different animals need to sort of-- so, I-- you know, how do you deal with that?
ANDY DOBSON: I get that-- that's going to be, I mean it relates to some of the things I talked about. In, I think, yesterday's lecture, I skipped over this slide, but this is essentially the human impact on African elephant range up to 2010. Going forward to 2050, the green areas are what's left for elephants. Everything else is converted to agricultural land. To feed humans, were inevitably going to convert tons of land into agricultural land unless we can improve the efficiency of agriculture. And tragically, that doesn't mean growing organic corn and all kind of beans. It means massively, intensely genetically modified.
AUDIENCE: Don't get me started there.
ANDY DOBSON: Well, that's going to be the only way that you are going to be able to grow enough people-- to feed those, to get enough food to feed people and save the land for the other species. If we go to the diet of sort of all-organic, living in sort of a happy bliss with our food, there will be no land left for anything else. And that's a sort of-- again, as I said, this talk will be about moral dilemmas. That's one where we've got a very mixed message, because this whole having organic food and having biodiversity are never going to be a compatible argument. So I worry about that.
The thing I worry about more, it was your first question, is why are we spending all this money on space? Why does our vice president want to have footprints on the moon? We can do that in 1,000 years time. It's not going to go away. We've learned very little of use to humanity from anything that's come out of the space program other than the satellites that look back down on the Earth and tell us how the Earth is changing. The rest is for the egos of a bunch of physicists whose brains would be better used looking at these problems on Earth. They're harder problems than rocket science.
AUDIENCE: Thank you for your talk. And apologies for being late. I was in class so I missed the first half. But I am in anthropology. And I also study China. And I am right now writing a paper about Chinese luxury consumption of things like rhino horn and ivory. So I am very curious about when you mentioned [INAUDIBLE] and I'd be very happy to know [INAUDIBLE]
ANDY DOBSON: Yeah, I--
AUDIENCE: But then I had a big question.
ANDY DOBSON: Yeah.
AUDIENCE: It is, I was struck by your account about the discovered imports of ivory to the US, are actually still bigger than imports to China, if I got you correctly. And I have been understanding this trend, the new poaching that took off, as you mentioned, from the '90s, as correlating [INAUDIBLE] with the rise of China, the investment-- China's investment plan [INAUDIBLE] it seems there is close correlation. So how then do we explain it? There's this, what's this trade in the US? Who's buying? And I feel [INAUDIBLE] who's buying in China and why. They have crazy business. [INAUDIBLE] But what about the US? What is [INAUDIBLE]?
ANDY DOBSON: Well, I mean lots of it, I say, is going to antique dealers, gun handles. The major states that we haven't been able to get any traction for a ban on ivory are the states where the NRA says, no, that will affect the sale of antique guns with ivory handles. And we go well, you know, what the f-- The second thing that goes to your point, yeah, if the stuff coming into the US is totally flat, and you're looking for a relationship between increase in poaching, then the only place you're going to get a correlation is between the line going up for China and the increase. But that doesn't mean that the US isn't still importing a ton of stuff. And it's like huh, I want to know where that stuff's going. And as I say, what we seem to be having to do at the moment is to go state to state, and talk to different people, and see where the resistance is in different states.
Another part of this is, you know, some of the most marvelous people out there are the US Fish and Wildlife people, who do a phenomenally good job on locating it. So this is stuff that's recovered under CITES, but they're doing-- they've got a very, very high capture rate. The people in China are not as efficient as that. We don't know what their efficiency is. So there could be much more going into China. But when-- that isn't being detected by CITES. So that would also distort this. But I just find it disconcerting that when you loo at the overall figures, there is as much-- there's more going into the US than there is going into China. That has then got to be modified. But how different are those detection levels? And this is all on a log scale. They could be 10 times different, and there would still be more stuff going into the US than into China.
AUDIENCE: You are saying that there is a huge amount of new, fresh new poaching going to the US, despite--
ANDY DOBSON: We don't know if it's newly freshly poached-- well, it's coming in. There isn't a huge amount of antique ivory being moved around between continents. So I suspect that lots of this is fresh ivory. And, you know, the last two years, there's been a huge ivory crush in New York. There's now one in Philadelphia, one in Denver, one in Los Angeles. There is tons and tons of stuff coming in that's freshly carved ivory that they've confiscated, US Fish and Wildlife, and they're crushing at these things. But I thought oh, well that's it. That'll be it for 10 years. It was as much the next year as it was the previous year. So that's a lot coming in.
AUDIENCE: And is it despite this widely talked about ban, Obama and Jinping both together, [INAUDIBLE]
ANDY DOBSON: That-- that's had the effect of slowing down, ironically, what's going into China. And trying to kill the trade in China has actually begun to bring down what's going on there. And so I've got to brave the CITES database to get the last two or three years data. But if you look at this, it does look as if China is slowing down since they made that agreement.
The US, ironically, isn't showing that slowdown.
AUDIENCE: How is that possible?
ANDY DOBSON: That's what I want to know. It's money. Yeah, it's money. And so what's driving it? And as I said, the cost of asking the wrong questions were met by my friend. This is not a nice bunch of people we're dealing with in these trades. However honest your elderly antique dealer looks, there's some very dodgy people supplying them.
AUDIENCE: That's really my question. So it's clearly needing this funding for CITES. But what about on the ground, corruption, for example if someone is starting to ask those questions and is assassinated So you've been working undercover for the last 25 years. Can you talk a little bit more about how we can fight the corruption on the ground?
ANDY DOBSON: It's tricky. I mean, all of us who work there get death threats, which is interesting, because it creates the dilemma, where do you put that on your annual report to the dean? It's like, community outreach.
But it's sort of, which one do you take seriously, and which ones are they just trying to sort of strong arm you? And plainly, I'm going to be much more cautious after what happened to my friend. Another friend who I have who's been working against the hunting lobby, he can't go to Tanzania anymore.
So it's a question of, how do you expose corruption without endangering yourself? And how do you do it like I'm trying to do here, by saying we can't just blame China, and we can't blame Tanzania, because if I look at these graphs from where the data is coming from, I'm as worried about what's going on in the US as I am in any of those other locations. So it's like saying, well, here's the information. Could we empower CITES as a larger organization, to be a bigger organization, and get in and expose corruption? And could we be honest about how connected it is to things like the arms trade and the drugs trade, both of which are run by pretty scary people as well. Yeah.
AUDIENCE: Can you guys see, by studying and working, are you seeing an increase in lion poaching as well
ANDY DOBSON: We haven't really detected that. Quite a lot of what's going into CITES, which is partly why I chose Singapore, there isn't a lot of live trade going through Singapore. Lots and that's why I said did not specifically look at stuff coming into the US, other than in this early figure, because a lot of it is stuff originally coming in for zoos, which would be live stuff, which has to be registered for CITES.
Similarly, there are huge amounts of primates brought in under CITES for medical research. And so it includes those things as well as dishonesty, or you less-honest [INAUDIBLE] uses, or stuff that's for sort of jewelry and frivolous uses. So again, it's disentangling-- and the CITES database does give you that information. But it's, as I say, it's a really clunky database to work with.
AUDIENCE: Have you guys looked at the poaching rates in the-- they're fairly new, so I don't know if it's out yet, but the new parks that are being created that they draft their borders and fences so the park spans across three countries. That would potentially maybe help move elephants up from the south to the north so they can re-populate? Have you looked at poach rates since there's now three countries [INAUDIBLE] see if they've spiked recently?
ANDY DOBSON: No, the countries that have got the huge multi-national parks would be, of course, from the Kruger into Mozambique. That seems to be working quite well. I mean, the problem is that there's still a cull of elephants in Kruger. So you open up the fence, some of the elephants will spill out into Mozambique, which would be good, because otherwise they would stay in Kruger and be culled. But Kruger has a policy that they want a certain number of elephants. So if they've gone into Mozambique, they won't be killed in-- culled in Kruger.
We've got-- people, we have elephants moving from the Serengeti into that Maasai Mara, across the border between Kenya and Tanzania. And we've had elephants from Amboseli going up into Kilimanjaro. And it's gone either way. Whenever the poaching is bad in Kenya, the elephants come down into the Serengeti. And our numbers of elephants that have gone up as the sort of poaching has increased and the hassle is increased around the Mara. But whenever sometimes we've had Amboseli elephants with collars on them have gone into Kilimanjaro, and professional hunters have said, oh, there's a nice elephant. I don't know why it's wearing a necklace, but let's shoot it. And it's like well, guys, you've got a license for a specific elephant. You shouldn't be out taking elephants that are long-term research animals.
So again, there's both the poaching and there's the hunting lobby to sort of wrestle with there. So certainly there are trans-boundary issues. And we're trying to look at ways of dealing with those. In general, opening up and letting the elephants move around, and other species as well, has been beneficial.
AUDIENCE: One more question.
AUDIENCE: I'm curious about, in southern Africa, where the populations are higher, are there troublesome impacts on habitat that we need to worry about as well, either for elephants or for other species?
ANDY DOBSON: I mean, yeah. As your elephant numbers build up, there-- I mean, a huge number of elephant researchers are looking at this whole business of human-elephant conflict. And you can have elephants in an area, you could fence them in, which I'm not at all keen on, but that stops them coming out and eating people's crops. And if people try and stop those crops, they may well get killed by the elephants, because the elephants in the dark just don't know who's attacking them, and will just sort of swing out.
As we go back through those maps-- where is it --there it is. This is only, you know, if you're going to have to convert Africa to a farm, and have the elephants in those small green areas, all around those areas you're going to have problems with elephants coming out and raiding your crops. So people have been looking at better ways to persuade elephants to stay in parks, which includes things like putting chili on posts around them, because elephants don't really like chili, putting recordings of bees, because elephants don't like bees. They get very nervous about getting stung inside their nose, which is the most painful place to be stung. So people are looking at ways to try and convince elephants that they're better off where they are. But elephants are super smart things. The older they are, they do remember. And, you know, if you go into a drought, the older individuals will remember where they went for water when there was a drought, and that will just take them out of the park and create a-- you know, it works great when it's rained a lot, and there's lots of food in the parks. When there's less food in the parks, they will run around and start taking crops that are even more valuable in the drought, because the crops are growing at a slower rate. So finding ways to deal with those conflicts is a major agenda for people working on elephants
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This lecture was presented in conjunction with Andrew Dobson's first campus visit as an A.D. White Professor-at-Large on October 15-21, 2017. Dobson is a professor of ecology, wildlife disease and conservation in the Department of Ecology and Evolutionary Biology at Princeton University. His research focuses on the ecology of infectious diseases and the conservation of endangered and threatened species.