Approaches to the Study of the Behavior of Sharks

Abstract

Many kinds of sharks are dangerous and apparently unpredictable predators whose behavior is virtually unknown. This is because they are difficult both to maintain in captivity and to observe in the field. However, the purpose of this paper is to review the behavioral information on sharks and, more importantly, to suggest approaches which will accelerate progress in understanding the activities of these animals. Shark behavior has been investigated within the methodological frameworks of both comparative psychology and ethology. Thus the underlying philosophies of these disciplines are briefly discussed. Six approaches for investigating the activities of sharks are presented. Approach I involved intuitive studies drawing upon natural history notes and fisheries statistics, and is typified by Springer (1967). This work set the stage for future quantitative research. Approach II is also intuitive. Here, as typified by Klausewitz (1962), inferences about behavior and ecology are drawn from morphologic and taxonomic considerations. Results appear to be useful in only the broadest of applications. Approach III, an ethological approach we term “structure of behavior,” rests upon direct observation of behavior. The basic rationale underlying this technique, including examples of field and laboratory studies with sharks, is given. While we are at a beginning stage in the ethology of sharks, this approach appears to hold great promise. Approach IV, the study of activity rhythms in sharks, is reviewed. Little is known about such rhythms, which represent short-term temporal activity. Practically nothing is known about long-term activity, i.e., behavioral ontogeny. In Approach V psychological studies of learning are reviewed with emphasis on habituation, operant and classical conditioning in sharks. It is concluded that learning probably plays an important role in the lives of sharks and that they are clearly not the stupid, blindly swimming creatures of folklore. In Approach VI studies of sensory physiology using behavioral techniques are briefly discussed. Results led to the conclusion that sharks are well adapted to detect and respond appropriately to a wide variety of environmental stimuli. Though the difficulties are real and many, the paper ends on an optimistic note, and it is felt that continued effort will unquestionably lead to a significant increase in our understanding of these fascinating animals.