The writer has been engaged over the last ten years in the study of the cognitive characteristics of bottlenosed dolphins. These studies contribute to the rapidly growing field of animal cognition. The description of the cognitive specializations, abilities, and limitations of different animal species can add importantly to our understanding of the functions of intellect in the natural world of the animal and of the pressures that may select for intellect. In turn, such study and analysis can place the theory and data on human cognition in a broader comparative perspective. We can hope to isolate special features of human cognition, as well as to identify those features which have parallels or precursors among animal species. The most recent work of the writer has focused on the ability of dolphins to learn to understand sentences expressed within artificial acoustic or gestural languages. The sentence is a hallmark of human language and has been identified by some analysts of the work in teaching languages to apes as fundamentally lacking in the strings of signs or symbols produced by the apes. However, work with the dolphins has emphasized the comprehension of language rather than language production. AS comprehension approach permits the experimenter to control the stimuli and cues available and allows for an objectivity and quantification that is lacking in much of the work on language production with the apes. The results of the dolphin language study, to appear in Cognition during this year, demonstrate the understanding of the semantic and syntactic features of sentences by the dolphins in either the acoustic or the gestural medium. The results have interesting implications for issues about the biological versus experiential features of human language, and suggest that at least some language skills may represent general cognitive structures rather than special language acquisition devices unique to humans. It is believed that discussion of the dolphin work, and of animal cognition in general, can expand the scope and depth of the Advanced study Institute on Cognition. Through the discussions, it is hoped that general theories of cognition can be considered or developed that can account for both human and animal cognition.