A life among the apes with primatologist Dr. John Mitani

This episode of The PrimateCast: Origins is taken from CICASP's International Primatology Lecture Series: Past, Present and Future Perspectives of the Field.

The IPLS is dedicated to providing origin stories told by experienced researchers in primatology and related fields. The lectures are conducted via Zoom within our CICASP Seminar in Science Communication for graduate students of our program at Kyoto University. We are releasing the audio from these lectures right here on The PrimateCast: Origins.

For anyone interested in viewing the video versions of these lectures, head over to the CICASP TV YouTube channel, where you can also watch them live as we stream our Zoom feeds there.

For the 8th international primatology lecture we invited Dr. John Mitani to share his origin story with us. This lecture took place on January 27, 2022.

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"If you find good [mentors], lean on them"
-John Mitani, 2022
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John Mitani is Professor Emeritus in the Department of Anthropology at the University of Michigan, who has conducted over 40 years of research on gibbons, orangutans, gorillas, chimpanzees, and bonobos. 

He is the 2022 recipient of the Charles R. Darwin Lifetime Achievement Award from the American Association of Biological Anthropologists. And, listening to his lecture really gives one a sense of why! So much of his work found its way into the textbooks.

In the lecture, he shares many of the key discoveries he and his colleagues have made about social behavior in primates. These covered topics like:

• territoriality and indices of home range defensibility 
• how ape vocalizations play a role in territorial defense and spacing
• how male orangutans can have hugely different mating strategies that coincide with huge differences in body size and other physical features
• how chimpanzee social behavior and alliances are determined by genetic relationships among males

He then goes on to provide some sage advice for any up-and-coming scholars out there. He spends a good deal of time acknowledging his mentors, and implores all of us to do the same. He also acknowledges the importance of serendipity, and the need to be opportunistic in the face of new observations. 

With eloquence and humility, John tells us the story of his career, in the hopes it can provide some inspiration to those of us out there on similar paths. 

One thing's for sure: I sure felt inspired after hearing him speak!

The PrimateCast is hosted and produced by Andrew MacIntosh. Artwork by Chris Martin. Music by Andre Goncalves. Credits by Kasia Majewski.

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Transcript

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john is is had had a very um rich and long career in in in primatology he's as as as is mentioned on the poster he studied almost if not all of the the the great apes and lesser apes um and he's covered an amazing variety of different topics um those of you who are just starting out on the field probably know him best for his work with chimpanzees and kibale in the ngogo site but he's done a lot of impressive work with with gibbon vocalization with orangutans as well as gorillas and and you know the whole the whole gamut so besides just a a great ape expert he's a great ape guy one of the very sociable kind empathetic um primatologists that i know in in the field and it's it's a great pleasure to have this opportunity to welcome him to present some of his experiences to all of you um listeners so without further ado i'll hand it over to john i'm sorry i didn't have that up until now but you can all see my screen now oh well thank you for um that kind introduction and giving me this opportunity to speak to you tonight um i'm especially pleased to have this opportunity since i have long-standing ties not only to japan but to japan primatology as well i find myself at the end of a very long career now and as i look back on the past 40 or so years the one thing that i keep on coming back to is how incredibly lucky i've been i've been lucky because i've had a unique opportunity to study the five animals depicted on the screen these of course are our closest living relatives the apes there have been many twists and turns along the way but if there's one recurrent theme it's that very little about what i'm about to tell you was ever planned because my story emphasizes the role that serendipity plays in science my story begins as all stories do in youth as i was growing up i had no particular interest in animals or their study or the their behavior but everything changed one day when i was a senior in high school this book arrived in the mail my parents had persia purchased it for my younger brother he's an architect now i got to the book first i stole it and it remains on my bookshelf to this day the book was called the marvels of animal behavior and was published by the national geographic society in keeping with the magazine the book was just full of these wonderful pictures of exotic animals and equally exotic locales i opened up the book and was immediately entranced as an added bonus the chapters were written by a veritable who's whose list in the study of animal behavior folks like dick alexander jack bradberry steve emlin gordon orions and my personal hero george shaller the chapter that intrigued me the most though was the final one a chapter written by irv devore on the boons i followed away what i could learn from the book and i went to college the university of california berkeley where sherry washburn one of the founding fathers of the modern study of primatology in america was teaching at the time i took a few classes and was immediately hooked now i was incredibly fortunate to go to school during the 1970s because these were very heady times in the study of animal behavior in 1973 carl von frisch conrad lorenz and nico tinbergen were awarded the nobel prize in physiology or medicine for their seminal studies in ethology two years later in 1975 ed wilson published social biology now it was in social biology send resurrected and renewed interest in bill hamilton's long forgotten theory of kin selection and when i heard about this idea for the very first time i started to wonder whether it would be possible to use some newly developed techniques designed to ask a genetic variation in natural populations and combine that with a behavioral study a study of something like a baboon to investigate whether who's related to whom actually affects who does what with him we took some of those ideas to graduate school where i was very fortunate to work under the supervision of peter rodman peter had just completed one of the very first successful field studies of orangutans in the wild and being trained at harvard and by devore and wilson he was thoroughly enmeshed in this emerging field of social biology my plans for graduate study were to evolve and change and they were to change quite quickly i remember sitting in class one day during my very first year listening to peter lecture about the conditions which would make it both easy and difficult for a group of primates to defend a territory i took the ideas that peter presented that day and with his help and guidance turned them into my first paper it was in this paper that we proposed an index of defendability a simple ratio of the average distance a group of primates traversed on any given day divided by a measure of the size of their range we reasoned that in situations when this index was large and exceeded one it would be fairly easy for a group of primates to move from one end of their territory to the other and defend it against others in contrast when that index was small and less than one the cost of defense would be prohibitive now this was a pre-internet age at a time when information wasn't instantly available at your fingertips so what did i do i did what you had to do back in the day i actually went to the library i dug into the literature i tried to discover what i could learn about the ranging habits of primates as it was then documented and when we put everything together we found that observations generally conformed to prediction now looking back on that paper i think it's fair to say that the paper helped introduce cost-benefit thinking into the study of primate behavior because it was one of the very first papers to explicitly acknowledge and recognize that there are costs as well as benefits to behavior the paper also got me to start thinking about how one actually goes about doing comparative studies of primate behavior and that was a theme to emerge in some of my later work where i investigated variation in the number of males and primate groups the role that male male competition plays in the evolution of sexual dimorphism and size and another study looking at the evolution of non-maternal caretaking in primates as i continued in graduate school my plans for phd thesis were changing and they took a very sharp turn at the end of my first year peter came up to me one day and asked whether i wanted to accompany him to warn you the next year he had a grant to study the social ecology of primates at the time and he needed people he needed students to manage field site i of course said yes and with that i became a primate field worker beginning with an utterly forgettable and failed attempt to study the behavior and locomotion of long-tailed mechanics peter actually sent me back a second time and that that study or that time in the field was equally unsuccessful so unsuccessful that i barely remember what happened i came back during my third year of graduate school to regroup and perhaps because of that paper we had just published on territoriality and primates my thoughts turned to this issue and i ended up developing a phd project investigating territoriality and primates i selected for study two animals that i be ca had become familiar with in my travels in borneo socially monogamous gibbons and polygenous leaf monkeys those gibbons live in fairly small territories they use them more or less exclusively they overlap minimally with their neighbors by contrast leaf monkeys live in equally small territories but ones that overlap quite extensively with their neighbors using some some results from a fabulous study that had just been completed by rich danaza on the rare and endangered claus gibbons as well as some theoretical ideas that had just been developed by steve emelin and lou ouring i hypothesize that the givens were defending space while leaf monkeys were engaging in a form of female mate defense now as an undergraduate i'd become quite fascinated and enamored of the work of nico tinbergen who had pioneered the use of field experiments to examine functional questions about animal behavior because of that i decided to implement a series of experimental playbacks using recorded calls to simulate encounters between gibbons and leaf monkeys at various parts of their territories the technique had been implemented successfully for the very first time in a wild primate by peter wasser in a study of mangabees in uganda peter wasser was to become a very important mentor to me he lent me some very expensive playback equipment and was later to serve on my phd committee now in my playback work with the gibbons i was able to show that both their vocal and their spatial responses waned as one moved out from the center of their territory to their boundary and into their neighbor's range results consistent with hypothesis that gibbons were in fact defending space per se while those were quite satisfying results my work with the leaf monkeys wasn't progressing nearly as well in fact i was failing and failing quite dismally my problem was that i couldn't have enjoyed the animals of my presence they were shy they were secretive they lived at fairly low densities and whenever we went out to look for them i'd rarely find them on those few occasions that i did i would only gain fleeting glimpses of them as they ran away quite quickly in the treetops intriguingly though whenever i went out to look for the leaf monkeys and failed to find them i would often run into something else orangutans and when i would run into one orangutan i would run into more than one orangutan they would often be together now i knew from reading the literature as well as peter rodman's own studies of these very same animals at this very same site that this wasn't supposed to be happening these were um supposed to be solitary creatures after about nine months of banging my head against the wall trying to um habituate the leaf monkeys to my presence i realized that it would be far more interesting if not profitable to switch my attention to the orangutans to figure out what they were doing when i did so i made a renewed commitment to field work i doubled down i spent as much time as i possibly could with the orangutans and when i did so i was able to document the alternative mating tactics employed by male orangutans now casual inspection of these animals will instantly reveal that there are two types or morphs of male aromatons there are those that are large as depicted on the left individuals who possess secondary sexual characteristics such as the feedy ch cheek flanges on that colored male alternatively there are smaller males that are about half the size as the large individuals now during these early days of studies it was quite natural to assume that this difference in size simply represented a difference in development the large individuals were adults and the small individuals had not yet matured they were sub-adults we now know of course that some of those small guys never grow up irrespective of whether the small male orangutans were old or young they were always at a competitive disadvantage due to their small size in order to compensate and to reduce the levels of competition that they face from the larger males the small males adopt the distinctly different alternative mating tactic one in which they first find a female they stay with them for as long as possible and here's where things get a bit nasty they forcibly and repeatedly make females the pattern shown by the small males differs quite dramatically from the pattern shown by the larger males the theme of male sexual coercion was to appear later in my life when i began teaching at the university of michigan there the very first class that i taught was a team taught seminar on the topic with my friend and colleague barb smutz barb later used some of the things that we learned from that class to write a very important review on this topic of male aggression and sexual coercion females in primates and other mammals my playback work with the gibbons was proceeding along and it was going along quite nicely so much so that i decided to implement the playback technique to investigate the long calls emitted by male 1 wrong guns these are some of the most distinctive sounds heard in the bornean rainforest and here my playback results indicated that males seem to use this as a spacing mechanism where low-ranking males generally avoided the calls emitted by the highest-ranking male in the area i could find no evidence that males use these calls to attract females to them now one's research interests often change as unexpected findings occur and given my work on orangutan mating behavior my thoughts soon turned to the uh puzzle created by given monogamy now monogamy mammals is both theoretically rare and theoretically unexpected and empirically rare found in only about 10 of all millions species and the problem has always been why do males accept these relationships here again i decided to implement a playback technique the playback technique to investigate this issue by simulating encounters between solitary females and made of pears when i did so i discovered that native females essentially impose these relationships on males by displaying sex-specific aggression toward other females with the passage of time that finding takes on renewed significance insofar as it bears on a current controversy over the factors that affect the evolution of social monogamy and mammals the old given result fits quite nicely with dieter lucas and tim clattenbrock's hypothesis that social monogamy evolves in situations where single males can't defend multiple females this because of high levels of female competition female intolerance creating low female densities now throughout my graduate career i was using the vocal signals produced by primates as a tool to simulate interactions between them and ask them questions about why are they doing the kinds of things that they were doing in the process it was impossible not to become interested in the sounds themselves it was for this reason that during postdoctoral research i decided to conduct studies of animal vocal communication here i was incredibly lucky to do that work working in the lab of peter marlar peter was one of the true giants in the study of animal behavior he was a recognized leader in the study of animal vocal behavior and coincidentally he happened to be the one who put together that book that originally caught my interest and attracted me to the field during postdoctoral research i spent most of my time trying to unravel the song sung by mel gibbons first showing how male givens use these as a species discrimination mechanism most of my time however in the marvel lab i was seeking answers to two questions how male song is structured acoustically and why were male singing what is the function of song with regard to the first issue male givens engage in prolonged singing performances during the pre-dawn hours those singing performances last about 40 minutes in length and male givens typically start those performances by emitting a series of fairly low amplitude short songs that consist nothing more than these frequency up sweeps as those singing performances continue those songs get louder they get longer and they get more complex in terms of their constituent notes with regard to the issue of song function my observations showed that males frequently countersink with their neighbors an observation consistent with a territorial spacing function additional observations indicated that song complexity increases during vocal interactions with neighbors with males singing faster louder and longer and with more elaborate songs than when singing alone i conducted a series of experimental playbacks to further probe the function of song and when i did so i discovered that males responded more strongly to elaborate songs some fast and loud compared to simple songs sung slower and at relatively low amplitude taken together those results suggested that increasing song complexity represents a series of greatest signals with long complex songs more effective territorial stimuli than short simple songs i concluded my time in the marler lab with this investigate with an investigation of the phonology song i began that study by decomposing the song sung by gibbons into their constituent note types i then created a mind numbing series of analyses that if i think back now still hurt today where i try to determine whether there were specific rules that gibbons use in stringing those note types together to construct their songs once i was able to do so i violated those rules constructing artificial rearranged songs as depicted on the right i played those songs back to the givens compared the responses to responses i got when i played back normal songs they responded differentially suggesting that there was in fact an underlying phenology to given singing behavior givens appear to string those songs together in the very same manner or in a similar manner that we do when we string together meaningless phonemes into meaningful words i conducted my postdoctoral research on gibbons at the newly established chauvin ponte research station in gundam holland national park in indonesia i found this place in the summer of 1984 with reese bowen and mark clayton and while i was there i also attempted to start a parallel study of orangutans that work has been continued to this day quite ably and quite nicely by cheryl naught and colleagues but my work with gibbons and orangutans at poland was cut short and was cut short because i was going to take a sharp turn in my research toward the end of the time my time in the marlow lab i was feeling as if i needed a new challenge peter marler was to issue that challenge by nudging me to the study of chimpanzees as things turned out he spent some time early in his career studying chimpanzees at gombe with jane goodall once i took up that challenge toshi sada nishida was there to facilitate my change in my switch to chimpanzees i met toshi earlier on a trip to japan and at a conference in america and when i was starting to contemplate this move to chimps i wrote to him and i asked him whether it would be possible to study the chimpanzees at the mali mountains where he'd been working for many years toshi agreed and i morphed into a chimpanzee field researcher for my first study i investigated an enduring problem in the study of primate and animal vocal communication whether learning affects the vocal acquisition process here i focused on the long distance pat hoots emitted by male chimpanzees and i asked whether there was dialectal variation this was an indirect way to get at the question of vocal learning insofar as local dialects are one correlate of the vocal learning process as we understand it in humans and male songbirds we compare the calls produced by males at the two well-known study sites in gombe and holly these sites of course are located within close geographic proximity to each other along the lake shore of uh along the eastern lakeshore of lake tanganyika and in our acoustic analyses we're able to document some subtle differences in the build up and climax phase of calls with males at mahali emitting buildups at faster rates and climax elements at higher frequencies than calls uttered by the gombe mills results consistent with hypothesis that there are dialects now in this paper we follow a lead first um proposed by bill mcgrew and caroline tooten we try to be careful to consider and eliminate other factors other factors that may have accounted for some of the acoustic differences that we had encountered or that we had uncovered this came to be known as a method of exclusion a method that was to be adopted in subsequent studies of chimpanzee cultural variation my first foray into the lives of um[Music] chimpanzees was a real eye-opening experience up until that time i had only i had only been working with socially monogamous givens and for the most part um solitary orangutans where the demographic situation obviously affected and constrained the form the frequency and the patterns of social interactions that could take place but here for the very first time i was actually working with truly social primates it became instantly clear that social factors affected virtually all aspects of chimpanzee life and behavior it was quick to recognize that dominance-ranked relationships affected call production this in a paper with nishida i may have been especially sensitized or sensitive to the fact that social factors would affect vocal behavior because while as a postdoc in the martial lab i had a good friend and colleague mars algae gear who was conducting an influential study on the alarm calling behavior of male chickens working together with steve karakashian and peter marler marcel documented the so-called audience effect in chickens whereby male chickens modulated the production of their alarm calls in the presence and absence of different cone specifics remembering that um study i asked whether something similar might be going on in chips and here again working along with nishida we're able to show that there was an audience effect in chips chips male chimpanzees actually modulate the production of their alarm calls increasing the number of calls they give in certain social situations specifically when their close friends and allies are in the party that day they seem to use these calls as a means to keep in contact with others but not with everybody only specific individuals only the kinds of individuals or the particular individuals that they like and associate with frequently i was later to merge these two seemingly disparate lines of research local plasticity as suggested by the dialect study and the effect of social factors on vocal production in this paper for years i was conducting acoustic analyses of chimpanzees calls often focusing on the long distance panhoop and in those papers and analyses we typically only examine single calls emitted by solitary individuals i knew however that males often called together in choruses with others for the most part we set those calls aside because spectrographically they're quite messy you had males calling on top of each other it was difficult to figure out who's who in those spectrograms but one day in my lab i made a fortuitous observation in examining some spectrograms of chorus calls i started to notice that the climax portion of those calls during choruses looked awfully similar to each other armed with that observation i then tasked julie rose lewis the arduous job of analyzing those chorus calls and when she did so she discovered that male chimpanzees produced acoustically similar clothes when chorusing together but they didn't do so all the time again they selectively did so when calling with their friends not with others the process seems to be similar to the process of vocal accommodation as we understand it in humans and i think this is something that most people can understand and identify and agree and understand vocal accommodation is this process whereby you start to adopt the different speech mannerisms customs habit even words of different people when you move to a different area it's seen as a way to fit it i recruited dick byrne to the dialect study as dick had um been to mulholly before and made some recordings well in scotland to obtain those recordings i ran into bill mcgrew i have this vague recollection of weaving down the streets of saint andrews late one night with bill turning to him and asking him whether the time is right for another meeting of great eight researchers this to recreate a meeting that had been held in austria nearly 20 years before that suggestion led to the publication of this book this book in term the result of this meeting of great ape researchers in mexico and here's where my life takes another serendipitous turn david watts happened to be a meeting up until that time david had been studying the behavior mountain gorillas of karasoki research center along with diane fossey and others david however was beginning to wonder whether he wanted to start studying something else something like chokes and in fact the very next summer he was planning to go to this place called lingogo in kibali national park to conduct a prime a pilot study when i learned of david's plans i immediately asked him if i could tag along and i had several reasons for doing so first reason was that i had no plans to return to mulholly the following year and i was looking for something to do secondly this was key bali it was a legendary field site it was a place that i always wanted to see it had been established over 20 years ago by tom strussaker who i knew as tom was one of peter marler's first graduate students so i already felt as if i was part of the hubali family i went the next summer and as an added bonus tom showed up i spent some of the best days i've ever spent in the field uh with tom walking in the ngogo forest day in day out trying to learn everything i could from him about ngogo kibali and uganda before tom showed up um i had already realized that ngogo was a very special place because there were chimps and they were everywhere this was because the community of chimps and goga is by far the largest that has been described anywhere on the african continent now this was only supposed to be a visit it was really a vacation i had every intention of returning to mahali the very next year to resume my studies of the mahali chunks with nishida who had developed a very close friendship and collaboration but with each and every passing day during that first summer at ngoga the lure being created by the go-go chimps was just too much to resist at the end of the summer i sat down with david i asked i asked him whether or what he thought about uh starting a joint collaboration and collaborative study in go-go chimps he agreed and the rest is history it's been a tremendously satisfying and productive collaboration i began my studies on lingo chimpanzees where i had left off at mahon with studies of their vocal behavior but right from the start i knew that this might be the place where i can fulfill that original dream i had in graduate school where i could do a study of kin selection and primate behavior so right from the very beginning i set out to try to obtain genetic data from then go go chimpanzees after several failed attempts we're finally able to coax mitochondrial dna out of some hair samples and that led to the publication of a few papers the results in these papers however were far from satisfying they were far from satisfying because at the end of the day they were only based on a single gene mitochondrial dna and that gave us only a imprecise understanding of who was actually related to whom i was only able to fill that dream i had in graduate school after i was able to recruit a brilliant young graduate student in the form of kevin klingergraber for his phd thesis kevin conducted and completed this heroic study where he typed an astronomical astounding number of genetic loci from a large sample of chimpanzees those genetic data gave us a fairly good understanding of who is actually related to him we combined kevin's data with my behavioral observations and were able to show that kinship mattered males who are related to each other at the level of maternal half-civs cooperate and affiliate in each of these six different uh content behavioral contexts far more frequently than do unrelated individuals i was able to extend that result by showing that those same maternal houses form long-lasting and enduring social bonds more recently one of my final graduate students at aaron zandel has shown that those bonds that are uh developed in uh that are formed or established and maintained in adulthood actually been begin in adolescence when males become independent from their mothers for the first time and in some other work my final graduate student rich noretti now at harvard studying uh bonobos has been able to show as others have in the past that sibling bonds persist following maternal loss as older siblings adopt and start to care for their younger siblings following maternal death our studies in the ngogo chimpanzees have provided insights into other aspects of their behavior including their honey as is the case at other sites chimpanzees and gogo hunt vertebrate prey and like at other sites their favorite prey are red colonist monkeys the unusual thing about hunting at ngogo however is that chimpanzees hot red calabas monkeys with very high success in proficiency those hunting success rates are so high that has led to a precipitous drop in the red call of its prey population over a 20 or so year period there's been an 80 to 90 percent drop in the number of red columnists at ngogo due to honey and as the chimps have decimated the population of red columbus at ngoga they've started other animals other animals that they barely touched 20 years ago we use some of our early observations at hunts to address an important theoretical problem about why male chimpanzees share meat and do so readily with others here we are able to validate an old hypothesis originally proposed by nishida who suggested that male chimpanzees use meat as a political tool to develop and maintain social relationships and bonds with others our studies on lingo chimpanzees might be best known for the insights that have been made into the question of topic of chimpanzee territoriality and this brings me full circle back to that very first paper i published on primate territoriality as is the case with many animals chimps are territorial interactions between members of different groups are typically hostile boundary patrol behavior is an integral part of chimpanzee territoriality and what happens here is quite interesting these patrols involve instances where groups that chose will gather together and move in quite directed fashion to the boundary of their territory often times entering the territory of their neighbors on some very rare occasions male chimpanzees or chimpanzees patrollers will encounter their neighbors and launch lethal coalitionary attacks on them for years our understanding of why chimps kill their neighbors proved elusive but after about 15 years of the study were able to provide an answer validating a hypothesis first proposed by richard rangham who suggested that chimpanzees kill their neighbors in an effort to seek dominance over them over the course of that ten years the ngogo chimpanzees killed several members in the community living to the northeast of their territory and after having done so and reducing the coalitionary strength of their neighbors to such an extent lungo chimpanzees were simply able to move in to that that a new territory usurp a large portion of the territory previously occupied by their neighbors we started to use the long-term data we've collected on the ngogo chimpanzees to address some long-standing issues about what makes us human here we oftentimes think of ourselves as being a bit unusual insofar as we display a slow life history we grow up very slowly we start reproducing relatively late in life and some of us if we're lucky we live a very long time our studies in the go-go chimpanzees now however show that chimpanzees there survive at very high rates across the entire lifetime at much higher rates than do chimpanzees elsewhere in fact the pattern of survivorship by the male by the chimpanzees atlangogo resembles the pattern shown by humans living in some natural fertility populations much more closely than does survivorship in other chimpanzee groups so here we've been able to reduce the gap between them and us in one important respect high survivorship among the go-go chimpanzees leads to a situation where chimps there live a lot longer than chimps elsewhere and this has paved the way for some collaborative work that we've been recently doing with we'll see emery thompson tony goldberg and others investigating the aging process here we've been able to show that fecal parasite loads increase as females age we have some suggestive evidence from two independent studies that the viral loads of male chimpanzees increase as they age and other work shows that the gut microbes of chimpanzees change as they age with young infant chimpanzees showing high gut microbial diversity a pattern that's directly opposite from the pattern shown by humans we have yet to publish our most surprising finding about the aging process in the go-go chimpanzees for now we have solid demographic and hormonal data that indicates some female chimps at ngogo experience menopause here we've known for a very long time that many female chimps and gogos survive into their 40s with some living well beyond the time they give birth for the final time if we compute leviticus and lackey's post-reproductive representation statistic we find that to be about 0.2 what this means is that a female chimpanzee had in gogo actually survives to an adulthood she's expected to spend about a fifth or about 20 percent of her entire life in a post-reproductive state now why these data are interesting i doubt that they're going to convince anybody that these females are truly menopausal but we have corroborating hormonal data for those same post-reproductive females show high levels of gonna have tropins and corresponding low levels of ovarian hormones and if anybody doubts the age of some of these chimpanzees that we have at uh ngogo we now have converging lines of evidence suggesting that these are really really really old chips um for the past few years we've been able mostly through sherlock able to recover the carcasses of some chimps who died and some of those older chimps are showing clear signs of not only osteoarthritis but importantly osteoporosis the defining feature of the ngogo chimpanzees has always been its size the community was large it's always been large it was large at the start but during the past decade the community has gotten even bigger that growth has been fueled in part by a secular increase in the fruit supply but with growth comes dissolution about three years ago the community finally fissioned with total spatial and social segregation between members of these two groups the split was a process it played out over the course of about three years where there's a gradual social and spatial separation between members living in these two groups it's quite interesting to watch if not unbelievable to see but some of these individuals especially these males who've lived their lives together grew up together were friends um all of a sudden turn on each other and start behaving aggressively for during that three year period not only did they start to separate spatially and socially but they also started to have encounters that were quite aggressive we marked the split by a particular event a particular event after which there is no no further interchange social interchange between members of these two groups and that occurred when members of the smaller group killed a young male from the larger group as if to place a stamp on matters the very next year members of the smaller group turned around and killed another older adult male depicted here in that larger group lest you think that things have settled down and everything's fine the saga continues and that smaller groups is still on a rampage just within the past year members of that smaller community have killed four chimpanzees living in the larger community one of whom was an infant born to this female last september now what if anything have i learned from all this and is there there anything that i might be able to pass on to some of the younger members in the audience today i began this discussion by noting how serendipity has played a large role in my life it'd be great to sit here and be able to tell you that everything that i just discussed in the past few minutes was planned and was planned meticulously right from the start and that everything worked out you'll now know of course that that would just be a lie we're taught as scientists to use current theory develop hypotheses based on that theory and then go out and test those hypotheses by conducting experiments or collecting observations but more often than not i think you're going to find that things aren't going to work out no matter how good the plan is how meticulous the study was at the beginning it's because of this that i've always told my students and anybody else who comes out in go go that the first role of a good field worker is that you have to be opportunistic you have to be flexible because things aren't always going to work out i urge people to be flexible and simply just keep your eyes up and follow the leads that your animals provide second some might view my career as a bit odd i started out as an experimentalist and i morphed into a simple observer of the natural world that was a choice and a choice that i made quite happily because there's nothing that gives me greater pleasure these days than going out and just spending long periods of time watching the chimps sitting back and letting them tell me their stories um the payoffs are far and few between because these are long-lived animals who give up the secrets of their lives to us as human observers only very slowly but when a discovery is made there's can be nothing more satisfying so maybe a second piece of advice i'd give to you would to be patient like me and maybe do something that i think far too many in this field are getting away from go to the field spend time with your animals watch them watch them closely if you do i can guarantee you that your animals will inform as well as surprise and delight i also started off by indicating how lucky i've been i'm quite fond of saying something that's absolutely true i've been to places and seen and done things that most people can only dream about along the way i've had the great and good fortune to have some wonderful mentors and great and uh good friends and colleagues with whom to work and along the way i've been quite generously supported by many private and public funding agencies i realize that everybody's different mentors colleagues are not always the same but if you find good ones i suggest you lean on them because this is a lot more fun doing together with others and it is always finally while i've been lucky i'd argue that you're lucky too you're lucky because you belong to this small collective the small collective of primatologists who have been given these wonderful opportunities to study an amazing group of animals our closest living relatives of non-human primates i've conducted research on the cooperative behavior of male chimpanzees for over 20 years now and something that's obvious was quite clear right from the start the collective is much stronger if we all work together than if we work alone and as individuals given that i'd urge you to do your research i know you're going to do it well but as you do so use every opportunity to do something to pay back contribute to the collective not only to ensure that primates will be conserved for future generations but also to ensure that others will be given the same wonderful opportunities that we've been given to work with these amazing animals with that i'll conclude but before i do i want to thank each and every one of you tonight for giving me this opportunity to speak to you and indulging this old man as i've taken the stroll down memory lane