SEXUAL SELECTION AND VOCAL SIGNALS IN GELADA MALES by Marcela E. Benítez A ...

192 Pages·2016·8.42 MB·English

by  Marcela Benitez

SIZING UP STRANGERS: SEXUAL SELECTION AND VOCAL SIGNALS IN
GELADA MALES

by

Marcela E. Benítez

A dissertation submitted in partial fulfillment
of the requirements for the degree of
Doctor of Philosophy
(Anthropology and Psychology)

in the University of Michigan
2016

Doctoral Committee:

Associate Professor Jacinta C. Beehner, Chair
Associate Professor Thore J. Bergman
Assistant Professor Ben Dantzer
Associate Professor Andrew J. Marshall
Professor John C. Mitani

© Marcela E. Benítez
All rights reserved
2016
DEDICATION

For my parents, María Elena and Rubén

For the sobre mesas, the treasure hunts, the science kits, the pajaritos que se rompió la patitas,
the soccer games, the asados, and the exotic pets. For filling my life with literature, art, music,
adventure, and most importantly love.

And for my older brother, Leonardo

For showing me that magic is real.

Y para ti, Abuela

Por esa pasión, ternura, y fortaleza que hoy corren por mis venas.

ii
ACKNOWLEDGMENTS

Over the past seven years, I have been incredibly fortunate to be surrounded by
exceptional mentors, colleagues, and friends at the University of Michigan. Their
knowledge, guidance, and support has been essential in every stage of my dissertation,
and invaluable to my academic development and overall personal growth. I am grateful
to have been part of not one, but two, incredible departments. To the faculty and staff, in
Departments of Anthropology and Psychology, thank you for you continued support and
for cultivating a community that encourages interdisciplinary research. To my peers and
colleagues, thank you for making this journey one of the most formative and memorable
experiences of my life.
Like most anthropologists, I have an interest in origin stories. Every academic
points to a handful people that have sparked their research interests and laid down the
foundation for their careers. I don’t know what my future in this field holds, but I do know
that my origin story begins here at Michigan and under the guidance of my brilliant
advisors Dr. Jacinta Beehner and Dr. Thore Bergman. I arrived at Michigan with a broad
interest in the relationship between hormones and cognition in nonhuman primates.
From the moment I stepped into Jacinta’s office, she worked with me to develop these
interests into research questions and predictions that could be applied to geladas. She
has continued to foster my research interests and aid in every stage of my
dissertation—from brainstorming to grant writing, data collection to final revision. In the
past few years, Jacinta has worked diligently in helping me become a better researcher
iii
and a better writer. She has been a supportive, enthusiastic, and engaging advisor and
I am so grateful to have had the opportunity to be mentored by such a distinguished
female scientist.
I am also indebted to Thore, who officially took me on as his student in my third
year. While much of my dissertation research stems from Thore’s work, he has always
encouraged me to develop my own research trajectory. I am grateful to Thore for
always asking the challenging questions and encouraging me to think critically about my
research and ideas. I was also fortunate to spend time in the field with Thore. From him,
I learned how to record vocalizations, analyze calls, conduct playback experiments, and
collect behavioral data. I could not have completed my fieldwork without his expertise,
guidance, field stories, and games of Celebrity.
I am also thankful for the guidance of my committee: Dr. John Mitani, Dr. Ben
Dantzer, and Dr. Andy Marshall. When Jacinta and Thore were on sabbatical in Ethiopia
during my 5th year, John became my surrogate advisor. His writing and career advice,
humor, and wonderful stories helped me push through the last few obstacles of
graduate school. Because of John, I leave Michigan with a better understanding of and
appreciation for both the field of primatology and the work of Irv Devore. To the newest
members of my committee, Andy Marshall and Ben Dantzer, thank you for your
continued feedback and professional guidance. I am fortunate that you both decided to
come to Michigan, and even more so that you agreed to join my committee.
I owe so much of my sanity, health, and happiness throughout graduate school to
my friends at the University of Michigan and in Ethiopia. To my gelada project big
siblings—Amy Lu, Eila Roberts, Noah Snyder-Mackler, and David Pappano—who
iv
paved the way through the program and through the Simiens, thank you for all the
advice, feedback, recipes, and stimulating conversation. To Julie Jarvey, Elizabeth
Johnson, Morgan Gustison, Caitlin Barale, Shayna Lieberman, and India Schneider-
Crease, who made the field and the office feel like home, thank you for the crazy
gibshas, the venting sessions, the work dates, and the late night dance parties. To all
the Biological Anthropology Graduate Students that I have overlapped with here at
Michigan—but especially Bethany Hanson, Dana Begun, Aaron Sandel, Rachna Reddy,
and Maire Malone—and to my cohort buddies—Jess Beck and Ashley Schubert—thank
you for being my co-pilots on this amazing adventure. I know you will all continue to be
an important part of my professional and personal life in the years to come.
This dissertation would not have been possible without the help of my friends in
Ethiopia. To the camp managers—Clay Wilton, Tara Hoshin, Levi Morris—thanks for
holding down the fort and making sure data collection always ran smoothly. To our
gelada experts—Eshete, Setey, and Ambaye—I am so grateful for your patience,
expertise, and kindness. Thank for dropping everything when chaos ensued and
running after the males to ensure that I always got the data. To the park rangers and
their families, and to my friends in Gondar and Debark, thank you for taking me in and
sharing your food, coffee, tej, and stories with me. I am a richer person for having
known you.
Of the many people who helped with my research collection, my field assistant
Megan Gomery deserves special recognition. As soon as we set foot in Ethiopia, it was
clear to me that I was incredibly fortunate to have hired Megan to assist with my PhD
data collection. Her independence, flexibility, and work ethic in those first few days
v
were impressive. The fact that she was able to maintain that level of commitment, hard
work, and energy for almost two years is incredible. When I sprained my ankle, Megan
collected all the necessary project data and independently ran the playback
experiments. Because of Megan, my field season continued without a hitch and we
were able to collect twice as many vocalizations, fecal samples, and hours of behavioral
data than I had originally intended.
I have been so fortunate to grow up in a house filled with books, food, music,
laughter, and love. Even more fortunate to have been surrounded by wonderful,
intelligent, strong, passionate, and loving people. I have an amazing network of brilliant
and caring family friends that have all left their mark. Thank you for the Christmas
dinners, the solstice parties, the museum tours, the wine, and your never ending faith
and support in my finishing.
To my mother and father, thank you for supporting me in all of my strange and
crazy adventures— from soccer to monkeys, Ricky Martin to Messi, Beverly Glen
Playgroup to Michigan. Thank you for igniting my curiosity, for fostering my interests,
and supporting my dreams, even if that meant a career working with monkeys. To my
brother, who has always paved the path and then gone off of it entirely, thanks for never
letting me be satisfied with the easy answers. I look forward to discussing this thesis
with you. To my sister, for showing me that, whether it be music or monkeys, passion
and hard work always pay off. To my Abuela, for filling my life with magic, animals,
telenovelas, and love. I am so grateful I got a chance to share this part of my life with
you. Lastly, to my partner and best friend, Chelsea Fisher, for enriching my life in every
way. I look forward to being your spousal hire someday.
vi
This dissertation would not have been possible without the generous support
from the National Science Foundation (Doctoral Dissertation Improvement Grant BCS-
1340911, Graduate Research Fellowship), the Leakey Foundation (General Research
Grant), Rackham Graduate School (Rackham Merit Fellowship, Rackham One-Term
Fellowship), the Departments of Anthropology and Psychology, and the International
Institute at the University of Michigan.
vii
TABLE OF CONTENTS
DEDICATION ................................................................................................................... ii
ACKNOWLEDGMENTS .................................................................................................. iii
LIST OF TABLES ............................................................................................................ ix
LIST OF FIGURES ........................................................................................................... x
ABSTRACT .................................................................................................................... xii
CHAPTER 1. INTRODUCTION & BACKGROUND .......................................................... 1
CHAPTER 2. THE FUNCTION AND COSTS OF GELADA MALE VOCAL DISPLAYS 21
CHAPTER 3. ACOUSTIC AND TEMPORAL VARIATION IN GELADA LOUD CALLS
ADVERTISE MALE QUALITY ........................................................................................ 49
CHAPTER 4. EVIDENCE FOR MUTUAL ASSESSMENT IN A WILD PRIMATE .......... 84
CHAPTER 5. MULTIMODAL SIGNALS IN GELADA MALES ...................................... 113
CHAPTER 6. CONCLUSION ....................................................................................... 144
REFERENCES ............................................................................................................. 152

viii