Our Research: Past and Present
Past groundbreaking studies of dolphin sensory perception, cognition and communication
The Dolphin Institute was formed initially in-part to support and enhance the world-renowned dolphin and whale research center at the Kewalo Basin Marine Mammal Laboratory (KBMML), located in Honolulu. KBMML was founded in 1970 by University of Hawaii professor Dr. Louis M. Herman.
Between 1970 and 2004, a principal focus of work by KBMML and TDI was on describing in detail the cognitive capabilities, limitations, and specializations of bottlenosed dolphins resident at KBMML. Innovative studies examined dolphin visual acuity and auditory discrimination; visual and auditory learning and memory; the interrelation of echoic and visual systems; capabilities for behavioral and acoustic imitation; self-reports of behavior; the ability to understand symbolic reference to real-world objects; the ability to interpret and respond to television scenes and images; and the ability to process and act on the semantic and syntactic information present in instructions given
through special artificial languages. Through these studies, KBMML and TDI researchers described many of the fundamental cognitive, behavioral, and sensory capabilities of bottlenose dolphins and illuminated the world community about dolphin intelligence including how dolphins may perceive and interpret their world. For synopses of some findings from our studies of dolphin perceptual abilities, cognition, and communication, please click on the dolphin research topics to the left. For more detailed information, please refer to the references at the end of each description. In addition, you can find a complete list of our dolphin research publications, as well as abstracts from many of the papers, in the menu to your left.
Current studies of wild spinner dolphins off Leeward Oahu
Along the Waianae coast of Oahu in early morning hours, spinner dolphins (Stenella longirostris) gather in shallow inshore waters (< 17 fathoms deep, median depth = 11 m) in Makua Bay, Pokai Bay, and Kahe Point after foraging at night in deeper waters (Lammers, 2004). These areas are used by the dolphins for resting, nursing, and social interactions. Dolphins are often observed milling in these areas in groups ranging from two to a hundred or more individuals. Often, large groups contain smaller sub-groups of individuals that vary unequally in sex and age-class (calves versus non-calves). Occasionally, individual dolphins may display surface-active behaviors (e.g., various in-air spins, slapping various body parts on the surface). In general, feeding is absent from bay behaviors.
To date, studies of the Leeward Oahu spinner dolphins have focused on general characteristics of the population for example their resting habitats, travel routes during times of the day, and general activity levels. (Lammers, 2004). Additionally, some work has been performed studying spinner dolphin acoustics (Lammers & Au, 2003; Lammers, Au, & Herzing, 2003; Lammers, Schotten, & Au, 2006). Although one published study examined long-term resights of a few spinner dolphins (Marten & Psarakos, 1999), little attention has been directed toward the underwater social interactions in conjunction with communication between individual spinners within and between groups.
Under Federal Research Permits, The Dolphin Institute is starting a long-term study of the social associations and underwater behavior and communication of spinner dolphins along the Leeward coast of Oahu. We will concentrate on photo-identification and concurrent behavioral recordings of social interactions of individual spinner dolphins. The gender of individuals will be determined through underwater observation. Sizing of individuals will be accomplished through underwater videogrammetry and related systems. Finally, communication will be investigated by recording vocalizations using passive acoustics (e.g., hydrophones that are part of the underwater video set-up). By recording behavior simultaneously with acoustics and individual body lengths and genders, we will determine the age/class and sex composition of various social groupings of spinners and examine how different vocalizations correspond to different behavioral states and interactions.
Past and present studies of Hawaii's humpback whales
Each winter TDI carries out studies of the humpback whales that migrate to Hawaiian waters for breeding and calving. KBMML pioneered research on Hawaii's humpback whales beginning in 1975. The research is directed towards an understanding of demographics, distribution, migration, social behavior, reproductive roles, and vocal communication of this species. Individual life histories of humpbacks are studied by matching identification photographs of whales across seasons. During our more than 30 years of study, we have
developed the largest whale identification catalog of any individual group in the North Pacific. Our studies have been conducted around all the main Hawaiian islands as well as in the whales' summer feeding grounds of Alaska. Our findings have contributed significantly to the understanding of the biology and behavior of humpback whales, have increased public awareness and concern for their protection, and have provided fundamental and necessary information to Federal and State agencies concerned with their conservation and recovery.