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5th+ Year

Caitlin Barale


My research focuses on primate development, and the ways in which peers and family influence social behavior, bonds, networks and reproductive trajectories. I am working with geladas (Theropithecus gelada), a Cercopithecine primate species endemic to the Ethiopian Highlands, in collaboration with the University of Michigan Gelada Research Project. My research follows a group of juvenile males from infancy into peer groups, and onwards to all-male bachelor groups. I combine behavioral observations, social network analysis, and non-invasive hormone analysis to address three main questions: (1) When and to what extent do juveniles participate in peer groups, and what are the influences of family and peers on this transition? (2) When and with whom do males form close male-male bonds, and what, if any, are the short-term benefits of these bonds? (3) As males transition into bachelor groups, do they maintain the bonds they formed during the juvenile period? What, if any, benefits are there to keeping these bonds as adults? Geladas serve as an excellent model for examining the effects of early life on development in primates, especially humans. Like humans, juvenile geladas split their social time between family members in their natal unit and unrelated peers in peer groups. This partition is very similar to the human child’s time-sharing between school and home. In both systems, juveniles learn, explore and receive information about how to become a functional adult in both the home and the peer group setting. Understanding the way social and behavioral influences affect adult gelada trajectories will yield insight into the way early life shapes human development. My research will also provide the first ever set of detailed behavioral and physiological data on wild juvenile geladas, which will allow me to answer fundamental questions concerning maturation time, dispersal timing, growth and development, as well as providing valuable information for conservation.


Andrew Berdahl


I am interested in both fish and collective behaviour in general, but my current research is focused on collective navigation.  Specifically I am looking at how simple interactions among individuals in a group not only enhance individuals' navigational abilities but can also lead to an emergent tendency for the group to travel in the 'correct' direction, even when this tendency is not present at the individual level.

Quing Cao


I am interested in the animal behavioral ecology and community ecology in the savanna-steppe ecosystem. In particular, my current research focuses on the resource use and niche differentiation of two sympatric equids (horse-like species) in Asia, the released Przewalski’s horse (Equus ferus przewalskii) and the indigenous Asiatic wild ass (E. hemionus). The niche differentiation driven by present competition is very rare and has been difficult to observe, especially in large mammals. Reintroducing once extinct species back to its original habitat may provide a good chance to examine how its realized niches form from the interspecific competition with another species with the similar resource requirements. My colleagues and I are working in Kalamaili Nature Reserve, using automatic camera traps and satellite telemetry in combine with observations to look at: 1) what are the fundamental and realized niches of the two equids, especially in food and water use, 2) how does the competition drive their resource use patterns, and 3) what kind of niche differentiations could allow the coexistence of the two species?

Xingli Giam


I have broad research interests in tropical conservation ecology and biogeography. I am currently studying the effects of land use change on freshwater systems in Southeast Asia. By combining field research and macroecological analyses, I will attempt to quantify the impact of land-use change on freshwater fish communities, with an emphasis on peat swamp forests. To inform conservation and land-use policy in Southeast Asia, I am currently developing spatially-explicit models of peatland deforestation in collaboration with Center for Remote Imaging, Sensing and Processing (CRISP) at the National University of Singapore.
Before starting graduate school in Princeton, I completed my B.Sc. (Hons) and M.Sc. at the National University of Singapore. Both degrees were completed under the supervision of Professors Navjot Sodhi, Hugh Tan, and Corey Bradshaw. Besides spending time with my family, I enjoy playing football (or soccer in the US), tennis, and table tennis in the little free time I have these days. My latest hobby is fish-watching in the nature reserves of Singapore.

Albert Kao


Through theoretical and empirical studies, I have been examining different aspects of how groups make decisions collectively. I am developing a theoretical model to describe how the wisdom of the crowds (whereby larger groups can make more accurate decisions than smaller groups or single individuals) is affected by complex environments. I am also studying a model describing how learning may work in a group context, and how this may allow group members with minimal communication or cognitive abilities to learn a behavior that promotes the wisdom of the crowds. I also perform experiments to empirically probe the same ideas that I have studied theoretically. I use fish and humans as my two model organisms to see how similar mechanisms of collective decision-making are across divergent animal taxa.

Ipek Kulahci


For my thesis, I integrate animal social behavior with animal learning and personalities to explore how social interactions influence information transmission in a group. When addressing social interactions, I also focus on the role of multiple sensory modalities in recognition of group members. This project is a result of my long term fascination with three aspects of animal behavior; animal cognition, especially how animals learn and make decisions in changing environments, social behavior, which provides unique windows into dynamic decision-making as social environment changes frequently and can be quite unpredictable, and animal communication which is the basis of all social behavior. I am also a strong supporter of conservation and wildlife protection, and believe that successful conservation efforts require a thorough knowledge of animal behavior. One critical piece of this knowledge for social species involves understanding how individual differences in behavior are reflected at the group level and whether group members learn from the experiences of others. Currently I work with ring-tailed lemurs (Lemur catta), a threatened species which is a perfect study system for addressing these questions, since individuals vary highly in their personalities, learning abilities, and social interactions which span multiple behavioral contexts and show remarkable complexity

Sebastian Munoz


Sebastián Muñoz is searching for ecological patterns in parasite communities among a wide range of host species and environments. A native of Chile, with a professional degree in Marine Biology, Sebastián uses diverse techniques to find and understand the rules governing species coexistance within these communities. He was first introduced to parasitology working in marine environments, studying the ecology of fish and mollusk parasites. At Princeton, he is expanding his research by looking at the influence of species distribution and their interspecific interactions on the structure of the parasite community. Thanks to a summer research grant from his Department at Princeton University and the travel allowance from his Fulbright International Science and Technology Award, he studied the macroparasites of the Tasmanian Devil, an endangered species with very limited parasitological information. This work estimated for the first time the exact abundance of parasites per host, and revealed what appears to be a new nematode species. As the Tasmanian Devil faces extinction due to a novel and contagious form of cancer, documenting their parasite communities could help researchers to better understand their defenses against infection, with important consequences for their conservation. In collaboration with a former Princeton student they carried out a study on how macroparasites may reduce inflammatory immune responses in songbirds. In the long term, his goal is to help to understand the underlying phenomena that drive the observed patterns in these communities.

Jenni Peterson


Jenni is interested in ecological aspects of global health issues, especially neglected tropical diseases. Her thesis research centers on Chagas disease and its vector, the triatomine bug. She is investigating both theoretically and experimentally if trypanosome coinfection can regulate populations of triatomines to the point where Chagas disease transmission is altered. She does her experimental research in Medellin, Colombia and theoretical work in Princeton.

Ann Thomas Tate


I am broadly interested in the evolution and ecology of immune systems, and I combine experimental and theoretical methods to study immunity at multiple ecological scales. My thesis project aims to elucidate the mechanistic basis and population level consequences of immune priming in insects using flour beetles (Tribolium castaneum) and their parasites and pathogens as a study system

Colin Twomey


Fish school, birds flock, and humans (sometimes) form crowds.  Collective motion, in each case, can exhibit varying levels of order driven by potentially very different interactions at the individual level.  How a group comes to adopt a particular level of order, and who in the group influences that adoption, has to do with the way in which information propagates through the group.  I study information propagation by looking at a group from three different scales: at the level of the individual, at the level of inter-individual interactions, and at the level of the group as a whole.  To study inter-individual interactions, I use techniques from computer vision to quantify the social information locally available to each group member.  At the individual level, I use techniques from machine learning to determine how an individual maps its local information to behavior.  Finally, at the group level, I determine how all those individual decisions collectively result in a change in group state, and the relative influence of each individual on that change.  My hope is that this strategy for analysis may be applied generally (at present, I mainly work with fish schools), and that it will be useful for understanding how information propagates, and therefore how influence functions, in any social group

Blair Roberts


I am broadly interested in mammalian social behavior and behavioral ecology and have participated in studies addressing socioreproductive and mother-infant behavior in equids, reproductive behavior in canids, and interspecies interactions and habitat use in captive ungulates. My current research focuses on mother-infant behavior and juvenile strategies in African ungulates. Different ungulate species exhibit contrary maternal care behavior and development strategies. I hope to determine the extent to which these different behavioral patterns are dictated by a species¹ environment and physiology, and which environmental factors are most important in shaping behaviors and strategies.

Nitin Sekar


Nitin Sekar is a fourth-year Ph.D. candidate interested in the functional ecology of endangered species, the relationship between ecosystem services and poverty, and policy related to wildlife conservation and equitable development in the Global South. The aim of his dissertation is to shed light on whether Asian elephants (Elephas maximus) are ecologically unique or redundant as seed dispersers in a disturbed, forested landscape typical of much of India. To understand this, Nitin is collecting data to identify the main alternative dispersers to elephants and to quantitatively compare the contributions of each of these animal species to the dispersal of seeds of three mammal-dispersed fruiting species in Buxa Tiger Reserve, India. Additionally, Nitin is pursuing a certificate in Science, Technology, and Environmental Policy (STEP) with the Princeton Environmental Institute and the Woodrow Wilson School. His policy work will look at whether the Indian government's voluntary village relocation scheme is likely to achieve its stated ecological and equitable development objectives, as well as whether voluntary village relocation is a cost-effective intervention.