Ngogo Chimpanzees on Patrol

Territorial boundary patrolling by chimpanzees is a striking example of group-level cooperation displayed by our closest primate relatives.

Chimpanzees patrol in groups for the same reason wolves hunt in packs, because what they can achieve working together far exceeds the returns of more individualized efforts.

A male chimpanzee named Wilson and his cohort jointly test the boundaries of their group’s region. Photo: Kevin Langergraber

Patrols are conspicuous events that occur when multiple individuals, typically male, travel to the peripheries of their territory and sometimes deep into those of their neighbors. During these incursions, patrollers become hypervigilant and behave in other ways that suggest they are actively searching for neighbors. If the patrolling males find members of a rival group, they will attack and sometimes even kill them.

Unlike other animals, who will fight when groups happen to meet at the edges of their territories, male chimpanzees seem to deliberately search for neighbors while on patrols, potentially putting themselves in harm’s way for uncertain gains.

So why do male chimpanzees choose to patrol when such forays may lead to violent, even lethal, encounters with members of neighboring groups? Patrols may benefit everyone by increasing the size of the territory and the food supply, but individuals also have the option to shirk patrol duty since unhelpful members are not punished or ostracized.

To determine how male chimpanzees manage to achieve and maintain this remarkable form of cooperation, researchers — led by Leakey Foundation Grantee Kevin Langergraber of Arizona State University’s School of Human Evolution and Social Change and Institute of Human Origins — examined twenty years of data on who participated in patrols in a 200-member-strong Ngogo community of chimpanzees within Kibale National Park, Uganda. The results of this study are published in the Proceedings of the National Academy of Sciences.

By combining analyses of patrol participation with results of paternity testing on 122 group offspring, Langergraber and colleagues found that, over the long run, patrolling paid off because it increased group size, which is important in determining success in competition against other groups.

“The Ngogo chimpanzees patrol and kill neighbors more frequently than any other chimpanzee group,” says John Mitani of The Leakey Foundation’s Scientific Executive Committee. Mitani has studied the Ngogo chimpanzees for 22 years.

By 2009, the group expanded the size of their territory by 22 percent over the previous decade after killing 13 individuals from a neighboring group. Because of their success in competition against other groups, the Ngogo chimpanzees benefit from an unusually good food supply and long life expectancies.

But patrolling is a potentially dangerous as well as energy-sapping activity, and time spent patrolling is time that cannot be spent eating or mating with females in the safety of the territory. The study showed that males varied in how often they patrolled, and it was no surprise that high-ranking individuals, who were likely to be in good physical condition, participated frequently.

In addition, males who had more offspring living in the group, and thus more to gain by territorial expansion, patrolled often. However, not all patrolling events could be explained by such short-term benefits, as many males patrolled when they had no offspring or other relatives living in the group to protect.

Why should males pay the costs of patrolling to benefit the relatives of other individuals? In this large group, reproduction was not monopolized by a few high-ranking males. Males who patrolled when they had no offspring were thus very likely to reproduce in the future.

So even if a male has nothing to gain by protecting relatives now, by patrolling and thereby protecting and increasing the size of the group, he can gain in the long run.

“We know that humans have means ranging from gossip to drastic punishment to aid cooperation in group settings,” Langergraber says. “The puzzle has been to explain cooperation in animal societies, where shirking would seem an attractive option.”

Most studies have focused on short-term benefits of cooperation, he adds, “but our study shows the benefit of long-term data collection, and also that we still have a lot to learn from these chimpanzees.”

Materials provided by Arizona State University.

From the Field: Marie-Hélène Moncel, Italy

Marie-Hélène Moncel was awarded a Leakey Foundation research grant during our spring 2016 cycle for her project entitled “Early evidence of Acheulean bifacial technology in Europe. New fieldwork at Notarchirico (Italy).”

The trench and whole sequence

The main goal of this project is to focus on the technological and subsistence behaviors of hominids at 700-650 ka (700,000-650,000 years ago) in Southern Europe in their environmental contexts, and to compare them to behaviors in the north of Europe, where occupations are considered to be episodic before 500 ka due to climatic constraints. The climatic data from Southern Europe attest to mild conditions, and more continuous occupations are observed, which may possibly be explained in some areas by the presence of rich volcanic territories.

The site of Notarchirico is in the region of Venosa in the Basilicata in southern Italy. This site presents an exceptional complex of sedimentary-volcanic deposits with several very well-conserved human occupation levels. Most of the deposits of the site are linked to the activity of the Monte Vulture stratovolcano and comprise seven archaeological levels with rich faunal and lithic remains, including some bifaces. A human femur attributed to Homo heidelbergensis was discovered in one of the upper levels of the sequence dated by 40Ar/39Ar, TL, ESR and ESR/U-Th (dating methods) between 610 and 675 ka. These results are consistent with results from faunal and macrofaunal studies, placing the sequence in the Ponte Galeria phase (Galerian, beginning of the Middle Pleistocene).

Marie-Hélène Moncel near the Elephas antiquus bone

The bottom of the sequence of the site is securely dated to more than 670 ka. But evidence from the oldest layers is still limited to former small test pits, and no dates are available for these levels. This site is a key site, yielding the earliest evidence of bifacial technology in Italy and a rich lithic and bone assemblage. The onset of bifacial technology occurred in Europe during the key time period of 800-500 ka, associated with some behavioral changes possibly related to Homo heidelbergensis dispersals.

Last summer, we re-opened excavations at Notarchirico site with an international and multidisciplinary team in order to enhance our understanding of the earliest Italian evidence of bifacial technology but also to characterize hominin behaviour in Southern Europe at 700 ka regarding raw material procurement, subsistence strategies and core technologies.

Bed of pebbles (level I2)

The team comprises researchers from the Département de Préhistoire, CNRS, Muséum National d’Histoire Naturelle, Paris, CEA Saclay, LSCE, Université de Bordeaux 1, Université Paul-Valéry Montpellier (France); Università degli Studi di Ferrara; Universitià di Roma “La Sapienza”, Universitià di Bologna (Italie) and Kenyon College (USA).

The fieldwork season focused on a sector located outside the building protecting the former excavations directed by Marcello Piperno. In the past, limited sampling in this sector had episodically identified the presence of older stratigraphic and archaeological units than unit F (670 ka by 40Ar/39Ar).

4 Level I2. Bones and artefacts

During one month, a 30-m long trench by 2 m wide was opened on the side of the hill, several metres from the building (Figure 1). The present day superficial soil cover (with a thickness of 30 to 50 cm) was stripped with a mini excavator, enabling rapid access to the in situ stratigraphic units, truncated by the erosion slope.

At the top of the trench, layers F and F1 (black volcanic sands), the last layers exposed by the M. Piperno excavations, were identified and used as a stratigraphic marker for the identification of the underlying units.

Bones of level 12

Below these two layers, four major units were observed and numbered G, H, I and J, each of which can be divided into sublevels: level G (G and G1), level H (H1a, b, c, H2a, b, c), level I (I1a, b, c; I2, I2a, b, c, d) and level J (J1, J2). The characteristics of levels G and I are similar to those observed in former surveys. However, level J at the base had not been previously identified.

Fieldwork focused on the oldest units H, I and J. They all contained paleontological and/or archaeological material in the test zones. For example, a whole Elephas antiquus humerus was uncovered in layer H1 (Figure 2). The top of layer H2 contained a residual pocket of small pebbles with lithics and bones. The oldest level, level J, also contained lithic material (pocket of sand not in primary position?).

Bone and flint core of level 11

The unit with the most material is layer I and an excavation was initiated in this level. It contains a bed of large pebbles (I2), covered with a bed of small pebbles (I2a) and a level of fine orange-coloured sediments. All these subunits contained abundant lithic and bone material. The bed of pebbles (I2) presents the most material and is a fluvio-lacustrine unit with traces of human occupation (Figure 3). Excavations were set up over a surface of 14 m² (units H, I and J), including 8 m² for level I2.

In the current state of knowledge, the following species have been identified: Elephas antiquus, Bison, Megaceros, Cervids, small bovids, birds … (Figures 4, 5, 6). Microfauna and sediment samples for malacofaunal studies were recovered through the systematic sieving of sediments. The study mission of this material, scheduled for December, will lead to more precise species identification and identify any possible anthropogenic marks. More than 200 lithic objects were recorded in level I, associated with the faunal material. They consist of discoid-type cores, flakes, tools (denticulates, sidescrapers) on small flint nodules (Figures 6, 7). In order to carry out microwear studies and residue analysis, the lithic material was not washed. Several objects on limestone pebbles were also recorded.

Flint core of level 1

The use of new methodologies and interrogations at Notarchirico on recently excavated material (such as microwear studies, for example) should provide information on thebehaviorr of these hominids in Southern Europe at 700 ka, including raw material management, methods of toolkit manufacture, tool functions and subsistence strategies.

We began prospection in a 3-km perimeter around the site and collected flint nodules as well as various types and shapes of pebbles from dismantled Pleistocene formations. Comparisons are underway in order to identify locally available mineral resources for hominids and to determine whether they collected them from the vicinity of the occupations or whether these nodules were available around the lake, like at most European sites from the 700-600 ka period.

Samples from the new excavation were collected for dating (40Ar/39Ar, ESR, ESR/U-series, TL), but also for mollusc and pollen studies in order to characterize the climatic context. Considering the types of deposits, this context could correspond to MIS 17.

Petrographic and techno-typological studies of the lithic artefacts, as well as the paleontological and archaeozoological study of the faunal remains are in progress. A microwear study will also be carried out on the lithic and bone material from the excavation, as well as the renewed study of the material from the former excavations by M. Piperno (University of Rome), including the hominid femur.



Introducing Our Spring 2017 Baldwin Fellows

Franklin Mosher Baldwin Memorial Fellowships are awarded to graduate students who are from developing countries and would like to pursue training and/or education abroad. In providing this opportunity The Leakey Foundation hopes to equip these scholars with the knowledge and experience necessary to assume leadership positions in their home countries where there often exist extraordinary resources in the field of prehistory.

The Baldwin Fellowship was established in 1978, and its track record speaks for itself. Baldwin Fellows such as Zeresenay Alemseged, Berhane Asfew, Mzalendo Kibunjia, Jackson Njau, Agazi Negash, Emma Mbua and Fredrick Manthi (to name only a few) have gone on to productive and influential careers in the fields of paleoanthropology and primatology.

Here are the three returning Baldwin Fellows for our spring 2017 cycle:

Kennedy Oginga

Kennedy Oginga (Kenya)

Mr. Oginga has a BS degree in analytical chemistry from Kenyatta University. He has been accepted into the master’s program in the Department of Geology under the sponsorship of Daniel Peppe. Last year he was nominated for a 3-month training at Turkana Basin Institute. At TBI he studied human evolution, archaeology, ecology, paleontology and geology. At Baylor his research will focus on using paleosols to reconstruct the paleoenvironment of early Miocene sites in Western Kenya.  He will present his work on the paleoclimate and paleoenvironment of an early Miocene site in Kenya (Koru) at the poster session at the AAPA this month in New Orleans.

Vidrige Kandza (Republic of Congo)

Mr. Kandza is in the master’s program at the Max Planck Institute in Leipzig. He has been working under the supervision of Karline Janmaat to pursue his research on food selection of the Mbendjele Yaka children foraging in a tropical rainforest. He intends to continue his studies as a PhD candidate and return to teach at the new Science University in Brazzaville.

Terry Mwanache (Tanzania)

Terry Mwanache

Mr. Mwanache has a BA in archaeology and heritage management from University of Dar es Salaam. He has been accepted into the Master’s program at Colorado State University sponsored by Michael Pante. He has worked as a field and lab assistant with the Olduvai Geochronology and Archeology Project and hopes to use the zooarchaeological and paleontological record of Olduvai to broaden our understanding of the evolution of the Pleistocene landscape and its influence on hominin behavior and evolution. At CSU this past year he acquired laboratory experience in bone identification and analysis, recording and documenting of archaeological materials, which he plans to apply to the conservation and preservation of archaeological materials through job opportunities in the Ministry of Antiquities in Tanzania. He expects to receive his Master’s degree this year.


Here are the four new spring 2017 Baldwin Fellows

Tengenu Gossa Aredo (Ethiopia)

Mr. Aredo has a Master’s degree in archaeology from Addis Ababa University. He is currently enrolled in a PhD program at the Hebrew University of Jerusalem under the supervision of Erella Hovers. He has been working at the early Acheulian site of Melka Wakena in Ethiopia in an attempt to understand  behavioral patterns of the toolmakers.  After completion of his studies, he plans to return to Ethiopia to either teach in a university or work with ARCCH to promote and conserve the Ethiopia’s paleoarcheological heritage.

Alexander Titan Kabelindde (Tanzania)

Mr. Kabelindde has been accepted in the PhD program in archaeology at University College of London. He has been working at Olduvai Gorge under the supervision of his advisor, Ignacio de la Torre and Jackson Njau. At Olduvai he hopes to shed light on the technological behavior of Homo erectus not only by participating in new fieldwork but also by analyzing the lithic assemblages from Beds III/IV. Upon completion of his degree, he plans to continue research in Archaeology in Tanzania

Himani Nautiyal (India)

Ms. Nautiyal is enrolled in a PhD  program at Kyoto University’s Primate Research Institute under the supervision of Michael Huffman. Her fieldwork is with a little studied species of Central Himalayan langurs living in a remote, high altitude Himalayan valley in northern India. Her focus is on male reproductive strategies and on the importance of female mate choice in influencing male reproductive success. She was awarded a National Geographic Young Explorer Grant in 2016.

Negin Valizadegan (Iran)

Ms. Valizadegan is a second year doctoral student in Biological Anthropology at University of Illinois at Urbana-Champaign. Her advisor is Jessica Brinkworth. The focus of Ms. Valizadegan’s research is the evolution of immune systems and microbe-host interactions in primates. She is interested in the interactions between beneficial microbes and their hosts to see how these interactions have led to adaptations between primates and their microbiota.  Her goal is to become a university professor in Iran.



From the Field: Julien Louys, Sumatra

Julien Louys was awarded a Leakey Foundation Research Grant in spring 2014 for the project “Palaeontological and archaeological investigations of Pleistocene cave deposits from Sumatra.”

Julien Louys

In 1887 M. Eugène Dubois set out to what was then the Dutch East Indies in search of the missing link. His first posting, in Padang, western Sumatra, provided him with access to the numerous caves that honeycomb the limestone hills and mountains in the surrounding highlands. From these caves, Dubois extracted hundreds of fossils—mostly teeth of large mammals—which would continue to be our only snapshot of Sumatra’s Pleistocene past for 150 years. In September 2015, our team arrived in Padang in an effort to retrace Dubois’s footsteps, and to forge new paths, in a quest to unearth Sumatra’s unique biological and environmental evolution over the last 100,000 years.

Our team, initially consisting of Dr. Gilbert Price (University of Queensland), Masters’ student Wahyu Dwijo Santoso (Institute Tecknologi Bandung) and me, and later joined by Dr. Yan Rizal and PhD student Agus Trihascaryo (both also from the Institute Tecknologi Bandung) began our survey from the small town of Batu Sangkar. We had acquired mudmaps of the location of Lida Ajer, Dubois’s most well-known Sumatran site, from Dubois’s fieldnotes and other researchers who had successfully located the cave some years before. Despite these, it still took us two days to finally locate the cave, as it turns out there are several caves in the region named Lida Ajer (literally ‘water tongue’). Having finally located the correct cave, we set about mapping the interior and collecting samples of speleothem and fossils for dating, critical for achieving our project objectives.

Orangutan fossil from Lida Ajer cave, Padang Highlands, Sumatra

Our project had four main objectives: (1) to relocate the Sumatran Caves described and excavated by Dubois; (2) to establish new sites in Sumatra; (3) to examine the depositional context of fossils in west Sumatran caves and determine their ages and their relationship to the Toba eruption; and (4) to examine the impact of the Toba eruption on the fauna and flora of Sumatra, and in particular the orangutan. The Late Pleistocene (~75,000 years ago) Toba eruption was the largest volcanic event of the Quaternary. Comparisons with historical eruptions, such as Tambora, Krakatau, and Pinatuba do not do justice to the sheer devastation wrought by this event. An estimated 2500-3000 km3 of pyroclastic ejecta was released from the volcano, and it is estimated that tuff from the eruption covered at least one percent of the globe. Understanding the impact of this eruption on ecosystems, particularly in Sumatra, was our primary reason for seeking these caves and the fossils they contained.

Once we had completed sampling Lida Ajer, we spent the next three weeks visiting a range of caves in the area; all in an effort to find new sites and relocate two of Dubois’s other sites. Unfortunately, unlike Lida Ajer, there is no good locality information available for the sites of Sibrambang and Djamboe, so we worked systematically from village to village, asking local inhabitants for information about caves in the area.

Entrance to Lida Ajer cave, Padang Highlands, Sumatra. Front of the cave is Dr Gilbert Price, at the left rear is Wahyu Dwijo Santoso

We then explored each cave, looking for the characteristic fossil-bearing breccia, which are often in the smallest nooks and crannies of cave passages. Despite our best efforts, we find neither Dubois site. We do, however, identify at least three new deposits of fossils in three different caves. Like Lida Ajer, we collect suitable samples to date the deposits where possible. These will be invaluable for reconstructing the history of faunal and environmental change in the region. Most deposits we identify are rich in orangutan teeth, indicating that these species were common on the landscape in the past – they are now sadly extinct from Padang; and in Sumatra today are only found around the Toba crater.

Analysis of the dating samples and the fossils we recovered is ongoing in the labs. We hope they will record periods from before and after the Toba eruption, thus allowing us to examine whether or not this event had a major effect on the hominid faunas of Sumatra.

Dr Gilbert Price examining a breccia deposit in one of the Sumatran caves.

Introducing Our Spring 2017 Grantees

The Leakey Foundation held our spring 2017 granting session on April 29, 2017. Our Board of Trustees unanimously approved twenty-nine research grant proposals for funding.

Here are some numbers from our spring 2017 granting cycle:

There were 111 applications for research grants this cycle.

31% of the proposals were categorized as behavioral, and 69% were paleoanthropology.

455 reviews were submitted to our grants department this cycle. Thank you to our reviewers! We could not do it without you.

We would like to congratulate all of our new grantees, and we look forward to sharing news and information about them and their research along the way!


Laura Abondano, University of Texas at Austin:  Mating strategies of female lowland woolly monkeys in Amazonian Ecuador

Iulia Badescu, Yale University:  Infant feeding and nutritional development correlates of fitness components in wild chimpanzees

Joel Bray, ASU Foundation for A New American University:  Social relationships in male chimpanzees: Form, function, and development

Elaine Gomez Guevara, Yale University:  Epigenetics of primate longevity

Sean Lee, The George Washington University:  The ontogeny of social behavior and facial form in Pan

Stefano Carlo Lucchesi, Max Planck Institute for Evolutionary Anthropology:  Role of ecology in intercommunity relations in bonobos, Kokolopori, DRC

Carrie Miller, University of Minnesota:  Does paternity certainty elicit protection and support of offspring by male gelada monkeys?

Sam Patterson, Arizona State University:  Maternal predictors of infant developmental trajectories in olive baboons

Megan Petersdorf, New York University:  The reproductive ecology of the little-known Kinda baboon (Papio kindae)

David Samson, Duke University:  What drives sleep flexibility? A comparative investigation of circumpolar and equatorial hunter-gatherers


Irisa Arney, University of Michigan:  East African Miocene evolutionary ecology

Amy Bauernfeind, Washington University:  Comparative gene expression of primate cerebellum

Aly Baumgartner, Baylor University:  Paleoclimatic reconstruction of the Miocene on Rusinga Island, Kenya

Marianne Brasil, University of California, Berkeley:  Skeletal morphology of early Homo sapiens from Middle Awash, Ethiopia

Lucia Carbone, Oregon Health & Science University:  Investigating how the LAVA retroelement shaped the gibbon transcriptome

Marco Cherin, University of Perugia: Exploring Site S:  New bipedal footprints at Laetoli (Tanzania)

Susanne Cote, University of Calgary:  Excavation of an exceptionally preserved Miocene catarrhine at Moruorot, Kenya

Harold Dibble, University of Pennsylvania:  A micro-contextual approach to Neandertal fire use at Pech de l’Azé IV (France)

Tamara Dogandzic, Max Planck Institute for Evolutionary Anthropology:  Late Middle and Early Upper Paleolithic in the Balkans

Emma Finestone, Graduate Center, City University of New York:  Examining the Oldowan through time on the Homa Peninsula

Mae Goder-Goldberger, University of Ben Gurion in the Negev:  The site of Far’ah II, western Negev, and the MP-UP transition

Andres Gomez, J. Craig Venter Institute:  Host-microbe interactions in the primate gut: Implications for human origins

Jason Kamilar, University of Massachusetts Amherst:  The evolutionary ecology of primate hair and skin microbiomes

Elaine Kozma, Graduate Center, City University of New York:  Climbing performance in African apes

Shannon McFarlin, The George Washington University:  Skeletal recovery and research of Bwindi mountain gorillas, Uganda

Enquye Negash, The George Washington University:  Modelling vegetation structure in modern ecosystems; Implications for hominin ecospace

Thomas Plummer, Queens College, City University of New York:  Excavation of ca. 2.6 Ma Oldowan sites at Nyayanga, Kenya

Christian Tryon, Harvard University:  Archaeology and modern human origins: Investigations of the Late Pleistocene Nyanza Rift, Kenya

Deming Yang, Stony Brook University:  Isotopic variability among Plio-Pleistocene Turkana suids: Paleoenvironments and hominin evolution