Brooke L. Sargeant, Ph.D., Post-Doctorial Researcher, Florida International University

Education

Ph.D. in Biology, Georgetown University, 2005
B.S. in Biology, Univ. of South Florida, 2000

Research Interests

Foraging Development and Ecology

One of the most important decisions for any animal is deciding what to eat and how and when to forage. I am interested in using optimal foraging theory frameworks to investigate whether animals maximize their energy intake or another type of currency, and what additional factors, such as predation risk and parental care, affect these foraging decisions. While simple models of optimal foraging have existed for decades, increasingly complex models evaluated in more ecologically valid contexts represent a relatively unexplored and fertile area of research. I am also interested in how learning (both individual and social) and environmental variability influence the development of foraging behavior and how patterns of foraging development differ between males and females.

Individual Specialization

Individual resource use often varies within and between populations, but the extent to which this variation is flexible (plastic, learned) or genetically based, and thus can contribute to the evolution of character displacement or species differences, is poorly understood. I am interested in proximate (e.g., habitat heterogeneity) and ultimate mechanisms (e.g., intraspecific competition) that can generate individual specialization. I am particularly interested in the interplay between social learning and individual specialization, and how different types of social transmission (vertical, horizontal, and oblique) affect the level of individual specialization or vice versa.

Social Learning

Social learning is emerging as a common and powerful adaptive mechanism for behavioral development. I am interested in exploring social learning and its functions. Is social learning more commonly used with greater environmental variability, or more difficult tasks? Do animals typically learn from kin, peers, or socially-dominant individuals? How often does social learning result in transmission of maladaptive information? These types of questions are just beginning to be addressed in wild animals in ecologically relevant contexts. Therefore, I am also interested in methods for studying social learning, imitation, and teaching in wild animals.

Foraging development in bottlenose dolphins of Shark Bay

As part of the long-term bottlenose dolphin (Tursiops sp.) research in Shark Bay, Western Australia, and in collaboration with Dr. Janet Mann, I study the development of foraging tactics in bottlenose dolphin mothers and calves. In particular, I am interested in how age, sex, social factors, and ecological factors promote the development of specific foraging tactics and how they

underpin the intrapopulation variation seen in Shark Bay.

Longitudinal research on mothers and calves has demonstrated remarkable variation in foraging behaviors among individuals, and suggests that vertical social learning is involved in the transmission of some of these behaviors. For example, sponge-carrying, in which dolphins wear marine sponges over their beaks while hunting, is used by a small proportion of the population and follows matrilines. We have also found that many tactics are associated with particular habitat features (e.g., seagrass beds, deep water) and that habitat use contributes to the development of some tactics. In order to investigate the contributions of multiple factors to foraging development, we are focusing on the use of multiple regression techniques and multivariate methods to identify cases in which vertical transmission is an important factor in foraging development.

To address these questions, we collaborate with other members of the Shark Bay Dolphin Research Project and with Dr. Mike Heithaus and Dr. Aaron Wirsing of the Shark Bay Ecosystem Research Project. Our findings shed light on factors that drive foraging diversity, including social learning, and thus have important implications for conservation of foraging habitats and of foraging "cultures" for this coastal cetacean. In addition, the development of foraging skills is likely a critical factor for weaning age, survival, growth, and reproduction.

Food web structure and carbon flow in aquatic communities of the Florida Everglades

With Dr. Joel Trexler of Florida International University, I am investigating food web structure and dynamics at the landscape scale in the Florida Everglades. We use stable isotopes to identify carbon sources and trophic position of small fish and invertebrates to understand how food flows though these communities. We are particularly interested in the role that detritus plays in the food web, a longstanding question in ecology.

By providing greater understanding of aquatic food webs at large spatial scales and the relative importance of detritivory, our findings will contribute to conservation and management efforts. We are also investigating individual specialization in the Eastern mosquitofish (Gambusia holbrooki), using carbon isotopes to determine if niche overlap varies with factors such as environmental gradients and/or population densities.

Publications

Sargeant, B.L. In press. Individual foraging specialization: Niche width versus niche overlap. Oikos.

Sargeant, B.L., & Mann, J. In press. From social learning to culture: Intrapopulation variation in bottlenose dolphins. In: The Question of Animal Culture (Galef, B.G., Jr., & Laland, K.L., eds.).

Sargeant, B.L., Wirsing, A.J., Heithaus, M.R., & Mann, J. 2007. Can environmental heterogeneity explain foraging variation in wild dolphins (Tursiops sp.)? Behavioral Ecology and Sociobiology 61: 679-688.

Mann, J., Sargeant, B.L., & Minor, M. 2007. Calf inspections of fish catches in bottlenose dolphins (Tursiops sp.): Evidence for oblique social learning? Marine Mammal Science 23: 197-202.

Sargeant, B.L., Mann, J., Berggren, P., & Krützen, M. 2005. Specialization and development of beach hunting, a rare foraging behavior, by wild bottlenose dolphins (Tursiops sp.). Canadian Journal of Zoology 83: 1400-1410.

Scott, E.M., Mann, J., Watson, J.J., Sargeant, B.L., & Connor, R.C. 2005. Aggression in bottlenose dolphins: evidence for sexual coercion, male-male competition, and female tolerance through analysis of tooth-rake marks and behaviour. Behaviour 142: 21-44.

Mann, J., & Sargeant, B.. 2003. Like mother, like calf: the ontogeny of foraging traditions in wild Indian Ocean bottlenose dolphins (Tursiops sp.). In: The Biology of Traditions: Models and Evidence (Fragaszy, D.M., & Perry, S., eds.). Cambridge: Cambridge University Press; pp. 236-266.

Curriculum Vitae

PDF version, May 2007