2015 Data Expeditions: Final Report
Kara Walker and Emily Boehm
In: Primate Conservation (EvAnth 359, Tara Clarke); Department of Evolutionary Anthropology
Title: Chimpanzee (Pan troglodytes schweinfurthii) interactions with other species: Records from the
Gombe Database, 1975-2011
The chimpanzees of Gombe National Park, Tanzania, have been studied continuously since 1960. Data
from this study, the longest running of great apes in the wild, is housed at Duke. Daily data collection at
Gombe occurs during follows of a focal individual, with narrative notes of social interactions, feeding
behavior, group movement, and party composition. Here, these data are digitized and organized into
Microsoft Access. Researchers in the Pusey lab query the database to ask questions about ecology,
sociality, and fitness. One fascinating aspect is interactions between chimpanzees and sympatric species.
For our data expedition, we created a table of over 4000 encounters between chimpanzees and other
species, often primates. These encounters range from peaceful feeding interactions with baboons (Papio
anubis), to alarm responses to venomous snakes, to predation on blue (Cercopithecus mitis) and red
colobus (Colobus badius) monkeys. We expanded an existing table in the database to include the
community membership of the focal animal, so that the encounters could be sorted between the two
communities represented. We also added information about the number of chimpanzees present in the
group at the time of the encounter and whether the focal animal was feeding.
This data expedition took place over two class periods in Dr. Tara Clarke’s Primate Conservation (Ev Anth
359) course in the fall of 2015. The first day served as an introduction to the project and dataset. We
emphasized the unusual size, length and depth of the Gombe database, which includes 50 years of
research and more than 300 individuals. We then gave a brief overview of the ecology of the park,
including the presence of other species, and discussed the importance of long-term research to
conservation. We encouraged the students to think about the relationships between chimpanzees and
each other species: Were they competitors? Were they predators or prey? Were the interactions
beneficial to either species? How does conservation of one species impact others? We then moved on to
detail the specific dataset that our students would use, explaining how we created the table, and what
each column represented. Together, we brainstormed questions, considering the limitations of our data,
and challenging students to think about how to balance interesting, biologically relevant questions with
feasibility. Students then split into small group to generate further questions. We asked each group to
bring two questions with corresponding hypotheses to the next class meeting.
During the second meeting, we reviewed students’ questions and tested one hypothesis together as a
group. This allowed the class to get comfortable with new programs and techniques. We emphasized
data manipulation in Excel—how to filter their data by multiple variables, write “if” statements to create
broader categories, and use pivot tables to generate counts and averages. Then, each group worked
independently to test one of their hypotheses, graph the results, and prepare a brief written report.
Based on our experience last year, when we found that simpler approaches were more successful, we
again chose to work with JMP, a statistical program available through Duke’s Office of Information
Technology.
To push the students to think beyond simple correlations between two variables, as a class we explored
a more complex test, looking at how encounter duration varied based on both the sex-ratio of the group
and whether the other species was a prey item. We created a 2x2 table with our predictions, and ran
two tests in JMP to complete the comparisons.
Examples of the questions posed by students: Do chimps encounter frugivorous species more frequently
in the dry season, when competition for fruit might be higher? Does the presence of estrous females in
the group affect the frequency and length of the interactions? Does the presence of juveniles in the
group increase the duration of the encounter (Fig. 1)?
Average Length of
Interaction (min)
Interspecies Interaction of Male Chimps
Based on Ratio of Swollen Females in Group
65
60
55
50
45
58.76887661
53.18936877
No Swollen Females Present
Swollen Females Present
Figure 1. Average duration of interspecies interactions of male chimps in groups with and without swollen
females.
The second iteration of this data expedition was even more successful than the first. We were able to
introduce new data manipulation concepts, and the majority of class time was spent working with data
in Microsoft Excel using pivot tables and graphing. Most students were unaware of either function and
had not previously manipulated a large dataset. As one student put it: “Wow! Excel is so powerful!” We
guided the students through statistical tests using the datasets they assembled. We have now
modularized our data expedition into three parts for use in future classes, independent of a Gombe
researcher: a power point presentation containing detailed notes; the dataset, with separate sheets to
explain each column and keys for Swahili words; and a hand-out explaining expectations for the
students’ final report.
Summary for a General Audience: Undergraduates studying Primate Conservation in the Department of
Evolutionary Anthropology explored the ecology of wild chimpanzees in Gombe National Park, TZ, using
a dataset of interactions between chimps and other species. Researchers who study the chimps gave an
introduction to chimpanzee behavior and the long-term Gombe database, then encouraged the
students to come up with their own questions and hypotheses for observed patterns of interspecies
interactions, such as, “Does the presence of juvenile chimpanzees increase the frequency and duration
of encounters with other species?” Working in groups, students learned techniques for organizing their
data and performing simple tests with statistical software. They enjoyed learning about these
charismatic animals and gained valuable research skills during this successful data expedition!