The population of white-faced capuchin monkeys (Cebus capucinus) in the Sector Santa Rosa (SSR) of the Area de Conservación Guanacaste (northwestern Costa Rica) offers a unique opportunity to model how landscape variability affected selection on early hominins.  This species shows many anatomical and behavioral convergences with great apes and humans, and they thrive in a broad range of environmental conditions, including the SSR, which could be considered a microcosm of early hominin environments.

In fall of 2010 Fernando Campos, PhD candidate at the University of Calgary, was awarded a Leakey Foundation research grant for his comprehensive examination of the effects of environmental change on this population of capuchin monkeys.  For this project Campos combined behavioral data collected over a period of 18 months with long-term census and demographic data, satellite imagery and genetic sampling. He summarizes his principle findings in the report below. 

Posted
AuthorH Gregory
CategoriesResearch Report

Simone Dagui Ban

Baldwin Fellow Simone Dagui Ban is a PhD student from the Félix Houphouët Boigny University in Côte d’Ivoire. Following the 2010-11 election crisis that made studying in her home country impossible, Ban was given the opportunity to study at the Max Planck Institute for Evolutionary Anthropology for one year.  She was awarded her first Franklin Mosher Baldwin Memorial Fellowship in the spring of 2013 so that she could return to Leipzig to continue her studies. Ban is now a second year Baldwin Fellow and plans on completing her PhD studies at Max Planck in December 2014. She will then be the first female in her country to have earned a PhD in primatology. 

Ban studies the ecological intelligence of chimpanzees, specifically the search strategies and memory skills they need to acquire ripe fruit.  She hopes to build on previous studies to gain further insight into what chimpanzees remember about feeding events (location, abundance of fruit, emotional state, etc.) and how these memories affect their ability and decision to revisit fruiting trees. The following is the abstract from her first paper published in the journal Animal Cognition:

The use of spatio-temporal memory has been argued to increase food-finding efficiency in rainforest primates. However, the exact content of this memory is poorly known to date. This study investigated what specific information from previous feeding visits chimpanzees (Pan troglodytes verus), in Ta ̈ı National Park, Coˆte d’Ivoire, take into account when they revisit the same feeding trees. By following five adult females for many consecutive days, we tested from what distance the females directed their travels towards previously visited feeding trees and how previous feeding experiences and fruit tree properties influenced this distance. To exclude the influence of sensory cues, the females’ approach distance was measured from their last significant change in travel direction until the moment they entered the tree’s maximum detection field. We found that chimpanzees travelled longer distances to trees at which they had previously made food grunts and had rejected fewer fruits compared to other trees. In addition, the results suggest that the chimpanzees were able to anticipate the amount of fruit that they would find in the trees. Overall, our findings are consistent with the hypothesis that chimpanzees act upon a retrieved memory of their last feeding experiences long before they revisit feeding trees, which would indicate a daily use of long-term prospective memory. Further, the results are consistent with the pos- sibility that positive emotional experiences help to trigger prospective memory retrieval in forest areas that are further away and have fewer cues associated with revisited feeding trees. 

Click here for the full article.

To learn more about the Franklin Mosher Baldwin Memorial Fellowship click here

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AuthorH Gregory
CategoriesJournal Article

In spring of 2013 Philip A. Slater, PhD candidate at the University of Illinois, was awarded a Leakey Foundation research grant for his project entitled "Planning and technological organization in the Kenyan MSA and LSA."  The following is a short update on his progress.

Small and intentionally dug hole that contained about 550 artifacts. The people at the site (~94,000 years ago) appeared to have dug a hole and swept up their mess - small sharp shards of glass from resharpening and shaping various types of tools.

My dissertation research, supported in part by The Leakey Foundation, focused on the long-term changes in stone tool technology that accompanied the evolution of modern humans in East Africa over the past 200,000 years. More specifically, I investigated the Middle (MSA) to Late Stone Age (LSA) technological transition and the adoption of standardized ‘blade’ technology during the LSA (≤50,000 BP). In order to assess levels of standardization I used a combination of typological classification and quantitative morphometrics to analyze obsidian artifact assemblages from three archaeological sites in Kenya’s central Rift Valley.

I found evidence for the systematic curation of late MSA artifacts, which contrasts with the systematic production of standardized LSA artifacts. Tools from MSA assemblages typically have long and complex use-lives, with repeated sessions of resharpening or reshaping maintenance. In contrast, tools from LSA blade assemblages tend to have short use-lives with very few bouts of resharpening. This tradeoff in longevity was counteracted by higher rates of production with standardized components that replaced used tools, rather than resharpening them. I also used scanning electron microscopy of use-wear patterns on individual artifacts to analyze their functions. This analysis provided independent evidence for the long use-lives of some classes of late MSA artifacts, such as points and scrapers, and shorter use-lives for LSA blade tools, most specifically microliths.

Some points (most likely for hunting spears) we found during the excavation

Together, these data provide robust evidence for evaluating the role of technological planning in the evolution of modern human adaptations. By standardizing and compartmentalizing the different production stages of blade tools, LSA knappers were able to more efficiently use their raw materials, time and energy. This technological efficiency is a clear expression of enhanced planning capacities in LSA humans, and provides support for subtle, but significant, advances in cognition during the late MSA. I plan to complete the writing of my dissertation by May 2015 and to publish multiple articles on different facets of MSA and LSA technological organization soon after. 


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AuthorH Gregory

Anne E. Russon and her team have been collecting field data on east Bornean orangutans (Pongo pygmaeus morio) at the newly established Bendili study area (northern border of Kutai National Park) since January 2010. Russon has been awarded two grants by The Leakey Foundation for her study of the ranging behavior and diet of this population, which due to the harsh environment is considered to be the extreme of orangutan adaptation. 

'Our' adult female in our Kutai National Park study area.  Photo shows her (Putri) with juvenile son (Pur) and new infant (no name yet, ca 1-2 mo old, against her belly hidden under her right hand).  Looks like Pur is trying to touch the baby. Mom's hand gently stops him. - Anne E. Russon   
Photo Credit:  Purwo Kuncoro

Posted
AuthorH Gregory
CategoriesFrom the Field

Erella Hovers
Institute of Archaeology, Hebrew University of Jerusalem

Excavation of ‘Ein Qashish

Traditionally, studies of Levantine (eastern Mediterranean) Middle Paleolithic sites have focused on caves, and so exploration of the open-air ‘Ein Qashish site presents a novel opportunity to expand our understanding of the behavioral dynamics of Middle Paleolithic hominins (modern humans as well as Neanderthals) in the region.

In the spring of 2011 Erella Hovers was awarded her fifth Leakey Foundation research grant for her project entitled “Exploring ‘Ein Qashish, a Middle Paleolithic site in northern Israel.” She proposed large-scale excavations at the newly discovered site so that her team could understand the site formation processes, test for spatial differences in the distribution of lithic and faunal remains, and characterize modes of site utilization. Finally, they would begin to reconstruct the ecological environment of ‘Ein Qashish.

In the report below Hovers briefly describes some of her team’s findings.  In addition, you may find the four papers that have been published on the ‘Ein Qashish research in Quaternary International by clicking here   

View of skull base and vertebrae within the depositional context

 

Posted
AuthorH Gregory
CategoriesResearch Report

Leakey Foundation grantee Alexandra Uhl, PhD candidate from the University of Tübingen in Germany, reports from the StEvE Conference.

EvE is a semester seminar series at the University of Tübingen with speakers who talk about their research in Evolution and Ecology. The StEvE conference is organized within the EvE for Students… So St(udents) and EvE = StEVE.  

Each year StEvE is organized by a different department at the University of Tübingen, and this year it was organized the Johannes Krause and Alexander Herbig of the Paleogenetics Department. They did a great job, and everything ran smoothly. We had two days of very interesting talks from a wide range of research fields. Most of the talks were on PhD research, but a few were also on MA research. There were drinks and meals where everyone could mix and discuss the research.

The conference was inside the Paleontology Museum of Tübingen, which was fun in itself. This picture is from the poster session. (You can see some huge vertebrae!) Note the Leakey logo on my poster (lower right corner next to my contact info). 

Posted
AuthorH Gregory
CategoriesFrom the Field

"These are some of the non-adult crania we scanned at Universität Tübingen. That's our CT scanner in the background. We also did DNA analysis on the teeth from these individuals."

In the spring of 2014 The Leakey Foundation awarded Alexandra Uhl, PhD candidate from the University of Tübingen in Germany, a research grant for her project entitled "Sex determination in geographically and ontogenetically diverse samples." 

My research looks at sexual dimorphism (differences between males and females) in the bony labyrinth, which is the rigid outer wall of the inner ear, across different modern human populations and different age groups. When human skeletal remains are found in an archaeological context, it can be difficult to estimate the sex of the individual if the bones and features that are sexually dimorphic, such as the pelvis and skull, are incomplete or broken. However, the bony labyrinth is housed in the petrous part of the temporal bone called the petrous pyramid, the best preserved area of the human skeleton and the most often found at archaeological sites and crime scenes. The petrous portion can even survive cremations. Since previous research on adult Europeans has found sexual dimorphism in the bony labyrinth, my research will explore this in world wide populations and different age groups.

Getting one individual ready for a batch scan at Witwatersrand.

Non-adults are extremely difficult to estimate sex for because they have not yet gone through puberty, which would make their bones more female or male. Thus, a technique that can be used on juveniles for sex estimation is extremely exciting, and since the bony labyrinth is fully formed in utero (before birth), sexual dimorphism should be present no matter what age an individual is. We plan to also apply the technique to Neanderthal and Upper Paleolithic specimens, for which sex estimation is also difficult due to robust features.

In September 2014 I went to the University of Witwatersrand in Johannesburg, South Africa to collect 58 scans of Zulu skulls from the Dart collection. I also measured the pelvis and post crania. In November 2014 I will go to Pennsylvania State University to make 40 scans of Oneota (pre-contact Native American) skulls and also measure the pelvis and postcrania. I also plan to do sex estimation using DNA analysis. I am working with a German skeletal collection At the University of Tuebingen, Germany as well.

Batch scan at Witwatersrand.  "This is how we saved time scanning. You carefully stack 2-3 individuals in the tube and set the scanner to do a batch scan. This way you don’t have to come back every 20 minutes to switch skulls, instead just every 40-60 minutes." 

A Zulu skull from the Dart Collection at Witwatersrand. Female, age 20.

Alexandra Uhl touring the Cradle of Humankind with Francis Thackeray

Alexandra Uhl at the Cradle of Humankind

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AuthorH Gregory

The Leakey Foundation is participating in the Amazon Smile program which will donate .5% of the purchase price of all eligible products that you buy if you sign up to support The Leakey Foundation. This is a simple way to support scientific research and science outreach at no cost to you! If you're an Amazon customer just follow these easy steps:

We appreciate your support very much, and if you're already supporting us with Amazon Smile, we thank you!

Leakey Foundation grantee Caitlin Barale studies wild geladas in Ethiopia.

Leakey Foundation grantee Caitlin Barale studies wild geladas in Ethiopia.

Another way that you can lend your support to the funding of human origins research and primate studies is to join The Leakey Foundation, and we now have a way to accept recurring donations! If you're considering becoming a member, please sign up to become a sustaining member. Your donation will be spread out in monthly installments rather than as a lump sum. With your support we can continue funding important research on our evolution, behavior and survival.

Posted
AuthorMeredith Johnson

Leakey Foundation grantee Isaiah Nengo (spring 2014) has recently returned from the field with exciting news!

Isaiah Nengo at work in the Lake Turkana Basin

Plio-Pleistocene sediments of the Lake Turkana basin have provided numerous fossils key to our current understanding of the origin and evolutionary history of the hominid lineage in Africa.  Scattered within the vast Plio-Pleistocene deposits are small Miocene sites documenting the evolutionary history of the ape lineage preceding and leading to the emergence of hominids.   I have teamed up with Ellen Miller of Wake Forest University on a field research program at the early Miocene of Buluk on the eastern side of Lake Turkana and on the southern side of the Lake at the middle Miocene of North Napedet.

Excavating a specimen

The Koobi Fora Research Project first surveyed the Miocene at North Napedet in 1990 and 1992.  A single canine belonging to a carnivore was recovered.  There was no further work at Napedet until the survey I conducted in February 2013, assisted by a Koobi Fora Research Project team. We successfully relocated the site, obtained GPS coordinates for two areas with dense bone concentrations, and collected a few mammal fossils.  The two weeks I just spent at North Napedet in August/September 2014 marks the first systematic collection of fossils from the Middle Miocene localities at Napedet.  Mr. Gordon Getty, through a Leakey Foundation grant, funded the fieldwork, while the Turkana Basin Institute and the Foothill-De Anza Foundation provided logistic support.

Isaiah Nengo and the team

I arrived at the Turkana Basin Institute Turkwel Facility on August 28, 2014.  The following day, August 29, I departed Turkwel and set up field camp accompanied by a 6-member crew.  The team members, all Kenyans, were four locals John Ekusi, Abdullah Ewoi, Akai Ekes, Bernard Ewoi, and the field manager Cyprian Nyete. We spent a total of 15 days at Napedet, arriving back at TBI Turkwel on September 13 and were able to recover a total 38 new specimens.  The new specimens include a canine of a hominoid, two maxillary fragments of a rare middle Miocene hippopotamid, and two remarkably well preserved fossil fruit. The most spectacular discovery was that of a complete and beautifully preserved cranium of an anthropoid juvenile.  

The study of the cranium is underway.  The study team members are John Fleagle, SUNY Stony Brook, Chris Gilbert, CUNY, New York, and Ellen Miller, Wake Forest. Fred Spoor, University College, London, has generously agreed to assist with the CT-scanning.  We plan to resume fieldwork at Napedet next summer to excavate the area where the cranium was discovered and to survey for new areas of bone concentration.  We also expect to launch, starting the summer of next year, a joint field school with Turkana Basin Institute to excavate two giant bone beds at Buluk.

Isaiah Nengo is a professor of anthropology at De Anza College. He earned his PhD at Harvard University and did his undergraduate work at Nairobi University in Kenya. His primary focus is to document origins of the ape lineage, the evolutionary roots of the human lineage, and the adaptive emergence of human bipedalism in the fossil record of the Miocene (approximately 25 to 5 million years ago) in Africa. He is the recipient of multiple Leakey Foundation grants.

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AuthorH Gregory

Nathan Thompson explaining to a kinematic subject how head motion relates to the semicircular canal organs in the inner ear.

Nathan Thompson, PhD candidate from Stony Brook University, was awarded a Leakey Foundation research grant in spring of 2014 for his project entitled "Kinematics and evolution of upper body stability in hominins."

Humans are unique among our primate relatives in how we move around our environments. With the adoption of bipedal locomotion, our ancestors were faced with the challenge of delicately balancing a heavy upper body atop a narrow pelvis. How we manage to accomplish this, without falling flat on our face at every step, is the focus of my dissertation work.

The human upper body functions to isolate the head from motion generated by the legs before it causes detriments to sensitive cranial organs. It also allows coordinated motion between segments to aid balance, stability, and efficiency during locomotion. I am investigating how the morphology of the pelvis, vertebral column, and head work together to mitigate motion in humans, and how morphological differences in our closest living relative, the chimpanzee, effect bipedal performance.

The Stony Brook Primate Locomotor Laboratory. Four high-speed cameras mounted on the back and right wall capture motion that occurs over the wooden runway (left). Embedded in the runway are four tri-axial force plates, which record the interaction between subjects and the ground.

Using high-speed cameras to record humans and chimpanzees walking, I can determine how much motion occurs between various regions of the trunk (pelvis, lumbar region, thorax and head). I also use small body-mounted accelerometers to measure high-speed, high-magnitude forces generated at heel strike, and how these forces are absorbed before they reach the head. By understanding how differences in trunk, vertebral and head morphology effect locomotion in humans and chimpanzees, we can ultimately hypothesize how differences seen in hominins would have effected early forms of bipedality.

Finally, my work seeks to elucidate the evolution of special cranial organs that govern aspects of locomotion, the semicircular canals. These organs have left their mark in many fossil mammals, including hominins. By understanding how differences in head motion reflect differences in semicircular canal morphology, we will be better equipped to use this information from the fossil record to reconstruct locomotion and behavior.

 

Video above:  A wireframe figure of a typical human and chimpanzee walking. Black lines represent the arms and legs. Colored shapes show the movements of the trunk and head (blue = pelvis, red = lumbar region, pink = thorax, and green = head). Three-dimensional motion of each region can then be calculated for each direction. The blue lines below each wireframe show the position in space of the pelvis in 3 anatomical planes.

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AuthorH Gregory

The peaceful and egalitarian northern muriqui of Brazil is one of the world's most critically endangered primate species. Fewer than 1,000 individuals remain in isolated forest fragments in southeastern Brazil.

Dr. Karen B. Strier discusses her 31-year study of the behavioral, ecological, and demographic changes of the northern muriqui in her lecture "Primate Conservation in a Rapidly Changing World." Dr. Strier has found that fluctuations in the ecological and demographic conditions in Brazil appear to have buffered changed in the muriquis' behavior. Her findings have implications critical not only to conservation on behalf of this species, but also to comparatively understand the adaptive potential and chances for survival in a rapidly changing world for other primates. 

"Humans Would Be Better Off It They Monkeyed Around Like the Muriquis" is a Smithsonian Magazine article describes Dr. Strier's work with the peace-loving murqui.

Dr. Strier is Vilas Research Professor and Irven DeVore Professor of Anthropology at the University of Wisconsin-Madison. She earned her PhD at Harvard University. She is a fellow of the American Association for the Advancement of Science, a member of both the National Academy of Sciences and the American Academy of Arts and Sciences. She has authored or co-authored more than 100 publications, including her monograph, Faces in the Forest: The Endangered Muriqui Monkeys of Brazil , and Primate Behavioral Ecology, 4th edition, a leading textbook in the field. Her new edited volume, Primate Ethnographies, calls attention to the human dimensions of primate field research and conservation efforts.

Tickets are now on sale at the Cleveland Museum of Natural History. $10 for general admission, $8 for members. Call the Box Office at (216) 231-1177 or visit the Museum's admissions desk to purchase tickets. 

This lecture is sponsored by Cornerstone Wealth Management, and it  is part of the Explorer Series at the Cleveland Museum of Natural History. The series is sponsored by Great Lakes Brewing Company and the Women's Committee of the Cleveland Museum of Natural History.

Posted
AuthorArielle Johnson

Julia Ostner
University of Göttingen

Female Assamese macaque

Researchers have been performing daily focal observations and fecal sampling on this study group of habituated Assamese macaques in Thailand’s Phu Khieo Wildlife Sanctuary since October 2006.  For her investigation of ecological, social and reproductive stress in female macaques, Julia Ostner used data collected between September 2007 and February 2009. This time period included two events that resulted in periods of marked social instability for the group, the death of an adult female and later that year the death of an alpha-male at the hands of co-resident males.

In the report below Ostner summarizes her team’s progress in disentangling the sources of physiological stress and their effects on female primates. 

Posted
AuthorH Gregory
CategoriesResearch Report
Fransdewaal.jpg

Empathy comes naturally to a great variety of animals, including humans. Individuals come to another's aid in a fight, put an arm around a victim of attach, or exhibit other emotional response to the distress of others.

"Ethics without God? The Evolution of Morality and Empathy in the Primates," a lecture by Frans de Waal, accompanies the recent release of his book "The Bonobo and the Atheist," exploring empathy's survival value in evolution and how it can help to build a more just society based on a more accurate view of human nature. Dr. de Waal demonstrates that animals and humans are preprogrammed to reach out, questioning the assumptions that humans are inherently selfish by studying social behavior in animals, such as bonding and alliances, expressions of consolation, conflict resolution, and a sense of fairness.

Tickets are now on sale. $18 for adults.

There will be a book signing after the lecture.

This lecture is sponsored by The Brown Foundation.

Frans de Waal shares his research on moral behavior in animals in this fascinating TED Talk.

"The Good Ape," a Scientific American MIND article, reviews and recommends "The Bonobo and the Atheist: In Search of Humanism among the Primates."

Dr. Frans de Waal is C. H. Candler Professor in the Psychology Department of Emory University and Director of the Living Links Center at the Yerkes National Primate Research Center, in Atlanta, Georgia. He is a member of the National Academy of Sciences, the American Academy of Arts and Sciences, and the Royal Dutch Academy of Sciences. In 2007, he was selected by Times as one of the "The World's 100 Most Influential People Today," and in 2011 by Discover as one of the "47 All Time Great Minds of Science."

Posted
AuthorArielle Johnson

Leslea Hlusko will give a free lecture on the campus of the University of Chicago entitled "Fossils, Genes, and Teeth: Reconstructing the Evolutionary History of the Mammalian Dentition."

October 9, 2014
12 Noon
BSLC 109
Dorothy and Gaylord Donnelly Biological Sciences Learning Center. 
924 East 57th St.

Leslea Hlusko's research team combines quantitative and developmental genetics with paleontology and neontology to elucidate the evolutionary history of the mammalian dentition.  She will present an overview of some of their more recent discoveries, highlighting how these seemingly disparate approaches can be combined synergistically.

Leslea Hlusko is Associate Professor of Integrative Biology at the University of California Berkeley. Her many research projects include the curatorial rescue of Mary Leakey's excavated fossils at Olduvai Gorge. She is a Fellow of the American Association for the Advancement of Science and the 2014 recipient of the American Cultures Program Innovative Teaching Award. She is a research associate with the Kenyan National Museums and the Cleveland Museum of Natural History.

Click here for a pdf flyer for the talk.

Posted
AuthorMeredith Johnson

Anne E. Russon and her team have been collecting field data on east Bornean orangutans (Pongo pygmaeus morio) at the newly established Bendili study area (northern border of Kutai National Park) since January 2010. Russon has been awarded two grants by The Leakey Foundation for her study of the ranging behavior and diet of this population, which due to the harsh environment is considered to be the extreme of orangutan adaptation.

Stay tuned for a research report from Russon. In the meantime, we thought we would share this picture and her comments (below).

CLICK IMAGE FOR FULL SIZE  Photo Credit:  Purwo Kuncoro  

Our 'resident' female Putri with a new infant (only 1-2 months old) and her older son Pur (6-7). In my humble opinion, son Pur looks not too happy - understandable given that his life would have changed a lot with the arrival of a new baby. Interbirth intervals in East Bornean orangutans (morio) may be shorter than they are in other Borneans or in Sumatrans. We've only recorded one birth so for and we don't know Pur's age for sure--but we've followed Putri and Pur since 2010 and we estimated Pur to be about 2 years old then. Even assuming that estimate was 1 year out (he was really 3), he'd still only have been about 6 when the new infant was born. So this birth tends to support the shorter-interbirth-interval possibility.

Further reading on Anne's work:

"An Orangutan Learns to Fish" - New Yorker
"Orangutan fish eating, primate aquatic fauna eating, and their implications for the origins of ancestral hominin fish eating" - Journal of Human Evolution 


 

 

Posted
AuthorH Gregory
CategoriesFrom the Field

The world is made less joyful with the recent passing of Dr. Irven DeVore. He passed away on Tuesday, September 23, 2014 from heart failure.

Irven DeVore . Photo from The Leakey Foundation Archive

Irven DeVore . Photo from The Leakey Foundation Archive

Irv joined The Leakey Foundation as a Trustee in 1974 and served until 1978. He became Co-Chair of the Scientific Executive Committee in 1980 and was later honored with the title of SEC Emeritus, joining his colleagues Clark Howell and Philip Tobias.

Irv was professor of biological anthropology at Harvard University. He began his fieldwork in 1959 studying the behavior and ecology of free ranging baboons in Kenya. Beginning in 1963, Irv directed studies of the !Kung San (Bushmen) of Botswana which led to the publication of two books, Kalahari Hunter Gatherers and Man the Hunter. He went on to co-direct a long term study of the Efe (pygmy hunter-gathers) and Lese (horticultural villagers) of Zaire.  

This obituary from the Boston Globe beautifully describes Irv, along with his rigorous scholarship, nurturing mentorship, humor and insatiable zest for life. He will be dearly missed by all of us at The Leakey Foundation.

The Annual Review of Anthropology presents Irven DeVore, Professor Emeritus of Anthropology at Harvard University, in conversation with Peter Ellison, Professor of Anthropology and Human Evolutionary Biology, also at Harvard University.

 

 

 

Posted
AuthorMeredith Johnson

Brigitte Spillmann, PhD Candidate
Anthropological Institute and Museum, University of Zurich

Photo:  Mure Wipfli

Photo:  Mure Wipfli

Brigitte Spillmann was awarded a Leakey Foundation research grant in spring 2010 for her PhD project focusing on the functions of the long call, the long distance signal of the flanged male orangutan.

Long distance signaling in widely dispersed, semi-solitary species is often used to mediate individuals’ ranging behavior and social relationships.  Such is the case with orangutans, whose long call is generally considered to be a means by which to repulse male rivals and/or attract potential female mates.  There is also evidence that there exists another function:  travel coordination between flanged males and non-receptive, female “friends.”  However, this may not always be the case.  Male-male competition and male-female relationships differ between Sumatran and Bornean populations, and consequently, their long calls do not always serve the same purpose or elicit the same response. 

Brigitte Spillmann. Photo:  Mure Wipfli

Brigitte Spillmann. Photo:  Mure Wipfli

In this project Spillmann set out to further elucidate the function and content of the long call in Sumatran and Bornean orangutans by systematically comparing the two populations.  Methods included collection of general behavioral data on full day focal follows; recording of long calls whenever possible during focal follows; playback experiments to test the immediate reactions and delayed ranging responses to both spontaneous and elicited long calls; and finally, utilizing autonomous acoustic monitoring (AAM), a grid of time synchronized recording devices used to identify and triangulate the locality of calling males.

The report below details the fieldwork performed by Spillmann and her team as well as their ongoing progress in combining AAM with focal follow data to construct a model of this communications network.




Posted
AuthorH Gregory