Los Angeles (CNN) -- 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 wasn'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.
CNN's Stella Chan contributed to this report.