ABSTRACT

Investigation of any unfamiliar object carries inherent risks but can also provide signi¢cant bene¢ts, including the discovery of new food sources. White Sharks (Carcharodon carcharias) combine numerous characteristics (e.g., large body, developed senses, broad prey spectrum, and few natural enemies) that should foster investigation of novel objects. Over a 13-year period (19972010), we observed White Shark investigatory behavior toward 26 ·oating objects and 61 strikes on seabirds at Seal Island in False Bay, South Africa. Attacks on seabirds were typically forceful and could have resulted from mistaken identity or been stimulated by contest competition from

conspeci¢cs. Nonconsumption of captured seabirds may also represent food rejection because of unpalatability or low fat content; however, we provide evidence that rejection of low-fat foods by White Sharks is inconsistent with quantitative studies of this species’ diet and with available data on dietary thermogenesis. The adaptive value of White Sharks’ observed behavior of biting objects that they do not consume is examined. We also present evidence that White Shark teeth function as mechanosensory structures, fostering tactile investigation.