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The Hawaiian Spinner Dolphin

Kenneth S. Norris
Bernd Würsig
Randall S. Wells
Melany Würsig
Shannon M. Brownlee
Christine M. Johnson
Jody Solow
Illustrations by Jenny Wardrip
Copyright Date: 1994
https://www.jstor.org/stable/10.1525/j.ctt1pnxxv
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    The Hawaiian Spinner Dolphin
    Book Description:

    Twenty years in the making by a distinguished dolphin expert and his associates,The Hawaiian Spinner Dolphinis the first comprehensive scientific natural history of a dolphin species ever written. From their research camp at Kealakeakua Bay in Hawaii, these scientists followed a population of wild spinner dolphins by radiotracking their movements and, with the use of a windowed underwater vessel, observing the details of their underwater social life. The authors begin with a description of the spinner dolphin species, its morphology and systematics, and then examine the ocean environment, the organization of dolphin populations, and the way this school-based society of mammals uses shorelines for rest and instruction of the young. The dolphins' reproductive cycle, their vision, vocalization, hearing, breathing, and feeding, and the integration of the school are carefully analyzed. The authors conclude with a comprehensive evolutionary analysis of this marine cultural system, with its behavioral flexibility and high levels of cooperation. This absorbing book is the richest source available of new scientific insights about the lives of wild dophins and how their societies evolved at sea.

    eISBN: 978-0-520-91354-7
    Subjects: Zoology

Table of Contents

  1. Front Matter
    (pp. i-vi)
  2. Table of Contents
    (pp. vii-xviii)
  3. FIGURES
    (pp. xix-xxiv)
  4. Introduction
    (pp. 1-13)
    Kenneth S. Norris

    This book is the result of a 25-year-long attempt to learn about the lives of wild dolphins. From the late 1940s to the 1960s, a scattering of behavioral observations of captive bottlenose dolphins accumulated (McBride and Hebb 1948, Tavolga and Essapian 1957, Tavolga 1966, Bel’kovich and Yablokov 1963, 1969). The conclusion from these studies was that dolphins are social mammals exhibiting a variety of patterns known from terrestrial species. They do not behave like fish but instead have set up reasonably typical mammalian societies in captivity.

    Although captive studies allowed consecutive and detailed observations over long periods of time, they...

  5. ONE The Spinner Dolphin
    (pp. 14-30)
    Kenneth S. Norris, Bernd Würsig and Randall S. Wells

    Most of this chapter describes spinner dolphins throughout the world. The last section introduces our studies of the Hawaiian subspecies, the main topic of this book.

    The spinner dolphin takes its common name from its unusual aerial behavior. Wherever the speciesStenella longzrostris(Gray 1828) occurs around the tropical and subtropical world, school members are reported to burst from the water and to rotate rapidly about their longitudinal axis for as many as about four revolutions before falling back into the water (Hester et al. 1963). On reentry after these leaps, some part of the body is slapped against the...

  6. TWO The Island Habitat
    (pp. 31-53)
    Randall S. Wells and Kenneth S. Norris

    One tends to think of spinner dolphins as mammals of the open sea. Yet wherever land punctuates the water masses within which spinner dolphins live, the land seems to attract them. Populations are now known to occur near many oceanic atolls, reefs, and high islands (see chap. 1).

    The size of the emergent land mass seems not to matter to dolphins so long as its shores offer adequate daytime shelter. Probably more important is a sufficiently large island pediment to influence the regular accumulation of foods (figs. 8 and 9). Schools of spinners come regularly to tiny Kure Atoll (Ocean...

  7. THREE Observing Dolphins Underwater
    (pp. 54-64)
    Kenneth S. Norris and Randall S. Wells

    A major challenge of the study of dolphin natural history is to place an effective observer under the water in the ocean where dolphins live out their life patterns. Nearly all studies of wild dolphin societies have relied upon observations made above the water or those made by listening under the surface (Pryor and Norris 1991, Tyack 1991). We describe some of these approaches elsewhere in this book. We made attempts to design balloons or kites that carry cameras or video apparatus, and we once built a gyrocopter to cruise over dolphin schools. However, for our aerial observations, we always...

  8. FOUR A Spinner Dolphin’s Day
    (pp. 65-102)
    Bernd Würsig, Randall S. Wells, Kenneth S. Norris and Melany Würsig

    The normal daily routines of an animal’s life provide the primary frame of reference within which most other behavior can be understood. For this reason, we begin our description of spinner dolphin behavior by outlining their movement patterns during an entire day-night cycle within the confines of Kealake’akua Bay.

    To obtain the data, we first established two observation posts. One was near sea level in front of our base camp (a rented waterfront house in the village of Napoopoo on the south limb of Kealake’akua Bay); this post was monitored twice hourly during daylight hours for the first year of...

  9. FIVE Aerial Behavior
    (pp. 103-121)
    Kenneth S. Norris, Bernd Würsig and Randall S. Wells

    The “trademark” of the spinner dolphin is its aerial behavior. An experienced cetacean naturalist can identify the species about as far away as it can be seen by its remarkable spinning leaps. But the spinner is not the only species of dolphin that performs characteristic leaps. Other species such as the common dolphin (Delphinus delphis), the right whale dolphin (Lissodelphis borealis), the beaked whales (Family Ziphiidae), the bottlenose dolphin (Tursiops truncatus), the rough-tooth dolphin (Steno bredanensis), the Pacific white-sided dolphin (Lagenorhynchus obliquidens), and the dusky dolphin (Lagenorhynchus obscurus) all have aerial patterns characteristic of their group. The mysticete whales also...

  10. SIX Population Structure
    (pp. 122-140)
    Bernd Würsig, Randall S. Wells, Melany Würsig and Kenneth S. Norris

    A species’ place in nature is delineated by the descriptors of its populations, reproductive patterns, associations, and movements. Traditionally, the information used in population analysis of cetacean populations has come from analysis of dolphins killed for one reason or another. For the genusStenella, studies of animals taken from the drive fisheries of Japan have contributed a great deal, as have studies of dolphins taken in the tuna seine fishery.

    The commonly caught striped dolphin (Stenella coeruleoalba), an open water relative of the spinner dolphin, has been studied both in terms of its population parameters and its social structure (Oshumi...

  11. SEVEN The Visual Domain
    (pp. 141-160)
    Kenneth S. Norris, Randall S. Wells and Christine M. Johnson

    One frequently reads of dolphins described as acoustic animals as if the sense of vision were unimportant to them. This is far from the case. Except for two riverine species,Platanista gangeticaandPlatanista minor, which are nearly blind (Purves and Pilleri 1973-1974), dolphins are equipped with excellent sight. In fact, dolphin vision is heavily involved in events both inside and beyond the school. In a number of ways, it is adjusted to the special environments in which dolphins live. To fully appreciate these visual environments, the observer must venture below the surface. These environments are very different from those...

  12. EIGHT The Acoustic Domain
    (pp. 161-185)
    Shannon M. Brownlee and Kenneth S. Norris

    Whenever spinner dolphins are active, they are noisy. Rest, at least when spinners enter bays, can be a time of almost complete silence. Some schools also must rest far at sea and these are not considered here. As the dolphins traverse slowly back and forth over sandy bottom, and if the school is of moderate or small size, only sporadic low level clicks and occasional whistles are heard. Overall sound abundance correlates generally with activity level, being low in low activity states such as rest and the slow-moving part of zig-zag swimming and high when schools are moving more rapidly....

  13. NINE Patterns of Reproduction
    (pp. 186-200)
    Randall S. Wells and Kenneth S. Norris

    As every behaviorist knows, a first order of business in beginning to understand a wild animal society is to define its reproductive patterns. This chapter examines spinner dolphin reproduction from two viewpoints. First, it outlines the patterns of reproductive seasonality found in Hawaiian spinner dolphin populations and the factors that seem to regulate these patterns. Then it outlines the reproductive hormone production of individual Hawaiian spinner dolphins and relates the results to social patterns. What little we know about reproductive behavior in wild spinner dolphin schools is covered in chapter 14, “Social Behavior,” while here we take up the physiological...

  14. TEN Locomotion
    (pp. 201-205)
    Kenneth S. Norris and Christine M. Johnson

    Most dolphins go about the majority of their daily activities at very modest swimming speeds, and Hawaiian spinner dolphins are no exception. Spinner schools typically move slowly. Most of the time in the bay, they could be followed by our slow-moving viewing vessel, which means that they seldom if ever exceeded 5-6 knots. Only during the last dash to sea in the evening did they speed up and begin to leap. Nighttime schools move rather slowly along the coast. But one must remember that these animals were also diving, sometimes to considerable depths as the school moved along, and our...

  15. ELEVEN Breathing at Sea
    (pp. 206-215)
    Kenneth S. Norris and Christine M. Johnson

    When the odontocete ancestor first became aquatic, it acquired a complex of difficulties relating to the handling of respiratory air. Over the many millions of years that followed, an exquisite series of adaptations has freed these mammals to swim freely, to dive and feed, and to phonate below the sea surface, often during long breath-holding sequences. This history of adaptation involved the alteration of many structural and physiological features of these animals. As a prelude to reporting on some simple but revealing observations about how spinner dolphins breathe at sea, we first review some of the major structural and functional...

  16. TWELVE Food and Feeding
    (pp. 216-231)
    Bernd Würsig, Randall S. Wells and Kenneth S. Norris

    Spinner dolphins are primarily feeders on small mesopelagic prey that they obtain by diving. Many of these prey species are vertical migrants coming toward the surface at night. Spinners routinely take several species that never reach the surface. Populations that frequent island shores or shallow embayments, such as the Hawaiian spinners discussed here or the Gulf of Thailand spinner (Perrin et al. 1987), also take bottom-dwelling species, and a small increment of surface-dwelling forms also enters the diet.

    This chapter first describes the mechanics of food capture and manipulation and then reviews and adds to the few published accounts detailing...

  17. THIRTEEN Schools and Schooling
    (pp. 232-242)
    Kenneth S. Norris and Christine M. Johnson

    A spinner dolphin never leaves the protective confines of its school. Although at first sight a dolphin school seems to be just a cluster of animals traveling together, we are beginning to realize that it is far more than that. Expressed in a school are patterns, signals, and processes that are relevant at various levels of organization above the individual. An entire lineage of toothed whales may be identifiable by a vocal dialect held in common by all members, as in the case of killer whales (Ford and Fisher 1983). Resting schools of spinners may merge into larger feeding aggregations...

  18. FOURTEEN Social Behavior
    (pp. 243-286)
    Christine M. Johnson and Kenneth S. Norris

    Our conclusions about social behavior presented in this chapter are based primarily on two sets of underwater observations: those made underwater in Kealake’akua Bay from the viewing vehicleMaka Alaand those made from the underwater viewing vault (fig. 86) of an oval 15-m (50-ft) diameter tank located at the Oceanic Institute on the island of Oahu, Hawaii, in which a small school of captive spinner dolphins was held (see chap. 3). TheMaka Alaobservations were made during several months of reconnaissance in which we attempted to understand as much as possible of the totality of underwater spinner dolphin...

  19. FIFTEEN Predators, Parasites, and Multispecies Aggregations
    (pp. 287-300)
    Kenneth S. Norris

    Attacks or successful kills by predators on healthy wild dolphins have almost never been observed. This is not particularly surprising in view of the long lives of dolphins and the limited observations that have been made of them in nature. Although they may be stalked frequently, their predators seldom succeed in catching them. Nonetheless, the high incidence of shark scars in some dolphin populations indicates the reality of predation as a force in dolphin societies.

    Stewart Springer, a well-known shark biologist, has provided an especially interesting record of sharks attacking a dolphin school, even though no dolphin was taken while...

  20. SIXTEEN Comparative View of Cetacean Social Ecology, Culture, and Evolution
    (pp. 301-344)
    Kenneth S. Norris

    This chapter covers what I consider to be the primary questions underlying this study. First, what do cetaceans do in their wild societies with their obviously high order cognitive development? What does it mean to the dolphin lineage that some species, at least, can perform mental abstractions and cross-modal transfers (that is, to be asked questions by visual means and indicate the answer by use of sound, an uncommon faculty in animals)? What does it mean that dolphins can remember long strings of unrelated numbers, perform high speed vocal mimicry, and be successfully trained to use symbols of speech, even...

  21. Overview
    (pp. 345-349)

    Now that we have done our naturalist’s best to examine the spinner dolphin with every tool and viewpoint we could contrive, what kind of animal emerges? Is the dolphin a truly different animal from its mammalian kin ashore, as some have imagined?

    The answer is, no, it is not different from other mammals ashore, except in ways that fit it to its special environment of the sea. In fact, one of the most important insights that this work highlights is that, in spite of the dolphin’s long separate history from other mammals reaching back almost to the origins of modern...

  22. APPENDIX A: Those Who Helped
    (pp. 350-354)
  23. APPENDIX B: Materials and Methods
    (pp. 355-370)
  24. Literature Cited
    (pp. 371-396)
  25. INDEX
    (pp. 397-409)
  26. Back Matter
    (pp. 410-412)