Project: Juvenile bottlenose dolphin social development and ecological and behavioral influences on survival in Sarasota Bay, FL



Photo © SDRP

The juvenile life stage is a fragile and formative time period for young animals first learning to navigate complex social and ecological environments once independent of their mothers. While bottlenose dolphins (Tursiops truncatus) are among the best studied cetaceans, virtually no work has focused on understanding behavioral development between weaning and sexual maturity or determining factors influencing survivorship of independent juveniles.

My graduate project is aimed at filling in this gap by working in the field under the direction of Randall Wells, conducting my dissertation research in conjunction with the longest-running research program on free-ranging dolphins in the world, the Sarasota Dolphin Research Program. Because of the long term nature of this research program, the “natural laboratory” of Sarasota Bay provides a unique opportunity to study juvenile dolphin behavior in a community where the animals are habituated to human presence, nearly all animals are individually identifiable, and over 90% of the resident individuals are of known age, sex, and genetic relationships.


The main objective is to better understand the social and behavioral development of bottlenose dolphins and to determine the major ecological and behavioral influences on survival strategies of free-ranging juvenile dolphins. To this end, I am addressing three major questions:

1) How do patterns of social behavior, activity, habitat use, and ranging develop over the course of the juvenile period from weaning to maturity?

2) What behavioral and ecological factors influence mortality/survivorship patterns of free-ranging juvenile dolphins?

3) What are the possible ecological and reproductive functions of mixed-sex subadult grouping patterns?

Photo © SDRP


This project combines information from the long-term datasets maintained by SDRP with new information collected through focal animal behavioral observations on a cross section of current juvenile dolphins in the Sarasota community. While the project does not involve any telemetry methods, such as radio or satellite-tracking, we are analyzing ranging and habitat use patterns of juveniles from sighting and follow GPS location data. By comparing and contrasting different behavioral, social, and ecological elements of the lives of juvenile dolphins, we hope to determine crucial ages at independence, better define social and behavioral maturity, investigate sex, seasonal, and age related differences in juvenile behavior, and better understand patterns of mortality and survivorship of free-ranging bottlenose dolphins in Sarasota Bay.


This project is in its final stages, with all field work having been completed in September 2008. Analysis and writing are currently underway with an aim to finish in 2009.


Katie McHugh (lead)

Randall S. Wells, Ph.D.
Chicago Zoological Society (Sarasota Dolphin Research Program

Pete Klimley, Ph.D.
Department of Wildlife, Fish, & Conservation Biology, University of California, Davis

Lynne Isbell, Ph.D.
Department of Anthropology, University of California, Davis

Funding Sources:

NOAA Fisheries; NSF Graduate Research Fellowship; UC Davis Graduate Scholars Fellowship, Animal Behavior Society’s Cetacean Behavior and Conservation Award, Chicago Zoological Society


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