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A Systematic Approach to Measuring the Social Behavior
of Bottlenose Dolphins
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,i.:i Sc,' 'I,¡ ~j ;.~ ~";WHOI-97-05 A Systematic Approach to Measurig the Socia Behavior of Bottlenose Dolphis by Amy Samuels Woods Hole Oceanographic Institution Woods Hole, Massachusetts 02543 September 1996 Techncal Report Funding was provided by the Chicago Zoological Society, the Dolphins of Shark Bay Research Foundation, the National Oceanic and Atmospheric Administration through Contracts No.
40AANF200358, 4OAANF201454, 40AANF201453 and by the Offce of Naval Research through Contract N00014-93-1-1181.
Reproduction in whole or in part is permitted for any purpose of the United States Government. This report should be cited as Woods Hole Oceanog. Inst. Tech. Rept., WHOI-97-05.
Approved for public release; distrbution unlimited.
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Submitted in parial fulfilment of the requirements for the Degree of Doctor of Philosophy at the Woods Hole Oceanographic Institution.
ABSTRACT~ r Cetacean biology is at a turng point with respect to studies of social behavior, a time of transition from anecdotal, descriptive natural history to focused, quatitative analyses of the social behavior of whales, dolphi, and porpoises. In my thesis, I seek to expedite ths transition in several ways. The first chapter is priarily about the cultural, or historical, factors tht have contributed to the methods of studying behavior and the ways of thng about behavior that are idiosyncratic to cetacean biologists. In subsequent chapters, I seek to demonstrate the effectiveness of systematic methodologies for a bettr understanding of the social behavior and social relations of bottlenose dolphins.
In Chapter 1, I provide an intellectual history of studying cetacean social behavior. Behavioral studies of cetaceans come from a very different background than such studies of terrestrial mamals, with a unique set of termologies, methodologies, and emphases. Beginng with the hunting tales of the early whaler-naturalists, this synthetic review describes the attempts to iner behavior and social strcture from studies of whale carcasses; the intimate observations of small cetaceans at early oceanaria; the pseudo-scientific explorations of human-dolphin communication; the decline of zoo-based research on cetacean social behavior; the evolution of present-day, long-term field studies; and the all-pervasive inuence of population biology. The review reveals that much of the groundwork has, in fact, been laid for the necessary next step: focused, quantitative studies of cetacean social behavior.
In Chapter 2, Samuels and Gifford investigated the agomstic behavior of bottenose dolphi at Brookfeld Zoo, using a quantitative technque adapted from primate behavioral research to determine dolphi domince relationships. Domice relations among dolphi were inuenced by the gender of participants. Male dolphi were clearly and consistently dominnt to females, and intersexual agonism occurred at moderate rates with seasonal peaks in spring and fall. Dominance relationships among female dolphi were age-ordered and stable, even though agonism among females occurred at uniformy low rates. In contrast, the two males had a changeable dominance relationship in which periods of stabilty and low-level agonism were interspersed with episodes of intense competition. Research in a captive settin faciltated development of a quantitative technque that can be used to assess domice relationships of wild dolphi. Zoo-based research also revealed pattern of behavior that conformed to current knowledge about societies of wild dolphi and generated predictions about the behavior of wild dolphi that can be tested using ths technque.
In Chapter 3, Samuels, Richards, and Mann investigated the association of wild juvenie bottlenose dolphi with their mothers. Female juvenie bottlenose dolphi continued to associate with their mothers for several years following weang. In contrast, juvenile sons rarely spent time with their mothers after independence even though they apparently remained in the same general area. Prelim results suggested that the broader social network of juvenile males may be quite different from tht of their female counterpar. In particular, sex differences in the social associations of juvenile dolphi appeared to foreshadow their adult social networks.
In Chapter 4, Samuels and Spradlin applied quantitative behavioral sampling technques to a management concern, evaluation of the behavior of dolphi in SwimWith-Dolphin program. Dolphi behavior in four captive programs was compared by the type of Swim encounter, defined by the presence ("Controlled") or absence ("NotControlled") of explicit trainer regulation of interactions between dolphins and human swimmers. Dolphin-swimer interactions involving aggressive, submissive, or sexual behavior were designated as "high-risk" when humans were swiming with dolphins;
sexual behavior was included as high-risk based on analyses that demonstrated cooccurrence of sexual and agonistic behaviors. High-risk activity comprised a substatial proporton of dolphin-swimmer social activity during Not-Controlled Swims. In contrast, high-risk activity rarely occurred during Controlled Swims, even though agonistic and sexual behaviors were normal components of the same dolphins' free-time social repertoire with other dolphins. These results indicated that direct trainer control of dolphin-swimer interactions virally eliminated high-risk activity from the Swim context, and thereby diminshed the potential for dolphi distress, swimer injury, and rejection of dolphins from Swim programs due to swimer injury.
These studies of bottlenose dolphi ilustrate the contributions of quantitative behavioral sampling technques and complementa studies in captivity and in the wild for a better understanding of the social behavior and social relationships of cetaceans.
Thesis supervisor: Peter Lloyd Tyack, Associate Scientist
I am especially grateful to John Farrington, Jake Peirson, and the WHOI members of the JCBO for resurrecting the WHOI graduate progr for me.
I th all the members of my commttee for their support, frendship, and good advice. I especially than Peter Tyack and Bil Watk who welcomed me into their labs as a colleague and provided the combintion of freeom and guidace tht I neeed to find my niche in cetace biology. Peter Tyack deserves special mention for patience and support above and beyond the call of duty, as exemplified in his unwavering encourgement even when I contemplated switchig to elephants after my originl disserttion project fell though. Bil Watk provided me with incredible experiences as a member of his sperm whale reseach team, including the opportnity to observe behavior on a very large scale. Aleta Hohn provided a common-sense sounding board on topics ranging from the evolution of life histories to swimg with dolphi, and set a model of scientific excellence for me to tr to emulate. Janet Man has ben a longtime friend and co-conspirator in the crusade to intil systematic sampling technques into studies of cetacen social behavior. Judy McDowell, the chair of my commttee, kept our discussions on track and was a perceptive and generous presence at all times.
I have been a student of anial behavior for many years prior to my enrollment in the graduate program at WHOI, therefore, the genesis of many ideas presented in this thesis pre-date my WHOI career. First, I wish to thank those who have been my mentors over the years: Jeanne Altmann and Joan Silk taught me how to study anial behavior, and Karen Pryor gave me a unique perspective on behavior though anial traing.
Steve Leatherwood and Sam Ridgway provided my first encounters with dolphi at Pt.
Mugu, and Ken Norris and Tom Dohl first introduced me to wild dolphins at Kealake'aka Bay. The years I spent observing baboons in Amboseli under the tutelage of Jeanne and Stuar Altmann has had a lasting impact on my thnkg about anal behavior. The time I spent observing wild bottenose dolphi near Sarasota, at the ~J invitation of Randy Wells, Michael Scott, and Blair Irvine, has forever inuenced my i thg about the social behavior and social relationships of dolphi. J~ The Chicago Zoological Society (Brookfeld Zoo) has supported me thoughout my graduate career in more ways that I can count. I am especially grateful to George Rabb, the director, and Pam Parker, whose joint idea it was for me to return to school for a doctoral degree. As frstrating as the experience has sometimes been, the wisdom of their edict prevailed: ths was the right thg for me to do. I than my collaborator at the zoo, Tara Gifford, for her long-term friendship and support, and I am grateful to the entire Seven Seas staff, past and present, for their assistance and for a unique sense, Cheryl and Doug Messinger, Mar of humor. In particular, I than Ed Kraj niak Sevenich, Tim Sullvan, and Jan Sustman for their special contributions to studying dolphi behavior in a captive setting. I also thank my colleagues in the Conservation Biology Deparent, especially Jeae Altman, Bob Lacy, Sandy Mane, Pam Parker, Linda Reiter, Tim Sullvan, and Randy Wells. Cindy Flahert deserves special thank for her friendship and dedication and for the many ways she has facilitated my absence from the zoo. Mar Rabb, I th for establishig an outstadin librar collection and for keeping me inormed about current publications. Truly, I thnk everyone at the Brookfeld Zoo for their interest, support, and good wishes over the years and for being tolerant of my unusual status at the zoo.
I have leared much from my colleagues in the Tyack and Watk labs. Laela Sayigh and I spent hours together, watchig and discussing the behavior of Sarota dolphi, and learg to be competent boat handlers. Kurt Fritrp was generous with his time to a fault, wiling to plunge into discussions of data anlyses or ideas at an time, day or night. I am forever in Kurt's debt for the miaculous retreval of inormation stored on my hard disk after my computer went up in smoke. Mar An Daher has provided friendship since I arved in Woods Hole and has been my main source of inormation about who's who and what's what in the WHOI community. Andy Read and Trevor Spradlin are tied for the title of "My Favorite Officemate." Both were more than generous with time and ideas. Trevor deserves special mention for his contrbutions to the Swim-With-Dolphi project and for his omnpresent support thoughout my WHOI caeer. Although I did not know Bil Schevil well, he has had a lasting infuence on my work though his writings and though the extensive library he collected with Bil Watkins. Cheri Recchia, Doug Nowacek, and Patrick Miler were always ready to listen and discuss. My other labmates have helped me in many ways, and I thank Nancy DiMarzio, Damon Ganon, Terence Howald, Debby Redish-Fripp, Liese Siemann, Lisa Taylor, and Rebecca Thomas.
The National Marine Fisheries Service sponsored the study of Swim-with-dolphin programs. Again, I thank Trevor Spradlin, my collaborator, as well as Aleta Hohn, whose good advice and sense of humor helped us to survive the experience relatively unscathed. Craig Pelton spent long hours observing the dolphi, and Cindy Flahert spent long hours tabulating data. I also thank Bil Windom, An Terbush, and others in the Offce of Protected Resources for their support. I am especially grateful to the staffs at Dolphi Quest, Dolphi Research Center, Dolphi Plus, and Theater of the Sea for their hospitality and cooperation during the study.
Dolphi of Shark Bay Research Foundation made it possible for me to conduct field research in Shark Bay, Western Australia. I thank my colleagues, Per Berggren, Richard Connor, Janet Mann, Andrew Richards, and Rachel Smolker, for welcomig me into the project and providing friendship and support. My collaborators, Andrew Richards and Janet Mann, helped me to learn the ropes and the dolphin of Shark Bay.
They have been guiding forces in nearly all phases of the project, and along with Rachel Smolker and Kelly Waples, provided long-term data for use in ths study. I am also grateful to Richard Connor and Rachel Smolker who intiated the long-term project on which my work depends. In addition, I than Cindy Flahert, David Charles and the rangers of Monkey Mia, Richard Holst and the Deparent of Human Biology at the University of Western Australia, Harvey Raven and his crew, the Monkey Mia Dolphi Resort, the Shie of Shark Bay, and the Departent of Conservation and Lad Mangement in Western Australia.
I thank my parents, to whom ths thesis is dedicated, for their encouragement and support long past the recommended cut-off for prudent parental investment. I am grateful to my friends -- Susan Albert, Jeae Altman, Bett Fuller, Pam Parker, Craig Pugh, Carol Saunders, and Kathy Twombly -- for their support and for helping me to see the light at the end of the tunnel. My swimg and runng companions, both human and cane, helped me to counteract the stupefying and back-wreckig effects of long hours at the computer.
Several dolphin have left me with lasting memories. I thnk Angie, Nemo and Stormy, Malia, #55, and Squarelet for allowing me the privilege of a glimpse into their lives.
Funding and logistical support for this work was provided by the Chicago Zoological Society. The Dolphi of Shark Bay Research Foundation also provided logistical support for fieldwork in Western Australia. Funding for the SwIm-WithDolphin study was provided by NOAA contracts No. 40AANF200358, No.
40AAF201454, and No. 40AAF201453 to myself, T. Spradlin, and C. Pelton, respectively. Additional support was provided from ONR No. NOOOI4-93-1-1181 to Bil Watkns and Peter Tyack.