Cortical complexity in cetacean brains


  • Patrick R. Hof,

    Corresponding author
    1. Department of Neuroscience, Mount Sinai School of Medicine, New York, New York
    • Department of Neuroscience, Box 1065, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029
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    • Fax: 212-849-2510

  • Rebecca Chanis,

    1. Department of Neuroscience, Mount Sinai School of Medicine, New York, New York
    2. Bronx High School of Sciences, Bronx, New York
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  • Lori Marino

    1. Neuroscience and Behavioral Biology Program, Emory University, Atlanta, Georgia
    2. Center for Behavioral Neuroscience, Emory University, Atlanta, Georgia
    3. Living Links Center for the Advanced Study of Ape and Human Evolution, Yerkes National Primate Research Center, Atlanta, Georgia
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Cetaceans (dolphins, whales, and porpoises) have a long, dramatically divergent evolutionary history compared with terrestrial mammals. Throughout their 55–60 million years of evolution, cetaceans acquired a compelling set of characteristics that include echolocation ability (in odontocetes), complex auditory and communicative capacities, and complex social organization. Moreover, although cetaceans have not shared a common ancestor with primates for over 90 million years, they possess a set of cognitive attributes that are strikingly convergent with those of many primates, including great apes and humans. In contrast, cetaceans have evolved a highly unusual combination of neurobiological features different from that of primates. As such, cetacean brains offer a critical opportunity to address questions about how complex behavior can be based on very different neuroanatomical and neurobiological evolutionary products. Cetacean brains and primate brains are arguably most meaningfully conceived as alternative evolutionary routes to neurobiological and cognitive complexity. In this article, we summarize data on brain size and hemisphere surface configuration in several cetacean species and present an overview of the cytoarchitectural complexity of the cerebral cortex of the bottlenose dolphin. © 2005 Wiley-Liss, Inc.