 Several apparently unprovoked attacks on humans have been attributed to the sicklefin lemon shark . Due to its formidable size and teeth , it is regarded as potentially dangerous , and certainly this species has been known to defend itself quickly and vigorously if touched , speared , or otherwise provoked or alarmed . Once agitated , this shark can be a persistent adversary ; in one case , a shark forced a swimmer to seek refuge atop a coral head , and circled for hours before giving up . However , observations by divers show that normally this shark is shy and hesitant to approach , even when presented with bait . Often , the shark will move away when a diver enters visual range . Young sharks are reportedly more aggressive and inquisitive than the adults . At Moorea , sicklefin lemon sharks are the main attraction of daily shark @-@ feeding ecotourism dives . This shark adapts well to captivity and is displayed in public aquariums . 
