A shadowy figure in a wave near children swimming at a southern California beach has experts disagreeing . Discovery Channel shark expert Jeff Kurr calls it a great white shark , but shark expert David Shiffman believes it was a dolphin . The beast was caught on camera lurking near June Emerson 's 12-year-old son and three young friends as they played in the Manhattan Beach surf Friday afternoon . The difference in the experts ' opinions centers on how they view the tail . `` This is not a # shark photobombing kids . This is a dolphin , '' Shiffman tweeted Monday . Shiffman , a recognized shark expert , noted in a Facebook posting that `` the tail is flat , '' like a dolphin , and unlike a shark . But in an interview with CNN , Kurr concluded it was `` a juvenile great white shark about 10 to 12 feet long . '' `` I would say based on the shape of the dorsal fin , which is more straight , that shows me it 's a great white shark , '' Kurr said . `` Plus , the fact that that particular beach has become the epicenter for white shark activity , I would say it 's definitely a white shark . '' Emerson told CNN that it was n't until on the way home from the beach that her son spotted the creature in one of the photos she took that afternoon . She remembers seeing dolphins in the water , but no sharks . Emerson told her son that it was a dolphin so as not to scare him away from the beach where they often swim . There are plenty of great white sharks in the southern California surf , but they pose no danger to beachgoers , according to Randy Hamilton , a shark expert with California 's Monterey Bay Aquarium . `` I just go back to the last 50 years on how many great white sharks have actually caused a death in southern California , '' Hamilton said . `` I only know of one incident where someone got a nip on the foot . '' The great whites around southern California are juveniles , also known as `` young of the year . '' At less than 18 months old , they only eat fish , Hamilton said . When the sharks approach adulthood , they relocate to the cooler waters near San Francisco where they change their diets to mammals -- sea lions and seals , he said .
It 's `` a juvenile great white shark about 10 to 12 feet long , '' expert Jeff Kurr says . `` The tail is flat , '' like a dolphin -- not a shark , expert David Shiffman says . June Emerson snapped the photo of her son and friends playing in the surf . Great white sharks are no danger to southern California swimmers , expert says .