A teenager from Australia lost her life while swimming with dolphins. An expert warned against joining the mammals when they are feeding in the water because it also means that sharks are around.

Expert Warns About Popular Myth About Dolphins and Sharks

Robert Harcourt, an Honorary Professor of Marine Ecology at Macquarie University and a regular surfer, warned swimmers to know what awaits them below the surface. There are myths that sharks and dolphins avoid each other. Some even claimed that it's safe to swim with dolphins because they scare the sharks away, according to Slate.

However, Harcourt argued that it's not always the case and told Daily Mail it was an "urban myth." The professor noted that bottlenose dolphins, which are common around the shores of Australia, often feed on the same fish that bull sharks and great whites consume too. They can also be prey themselves.

He warned that when dolphins move fast and change directions quickly, it means that they are feeding, and when they do, chances are high that sharks are around, too, feeding on the same school of fish.

In 2004, Rob Howes, a lifeguard, was swimming with his teenage daughter and her friends off the northern coast of New Zealand. They came across a pod of dolphins. Then, they noticed that the cetaceans "herd" them.

Shortly afterward, he realized what he suspected was true because they saw a nearby three-meter-long great white shark. He told NZ Herald that the dolphins protected them for the next 40 minutes from the sharks.

However, Harcourt said it didn't mean the dolphins protected the swimmers. Instead, they were using the concept of safety in numbers. Dolphins reportedly avoid sharks through group vigilance.

He also warned the people never to go in the water when some fish sporadically jump out of water because that could mean something is chasing them.

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Girl Dies From Shark Attack While Swimming With Dolphins

Stella Berry, 16, was with her friends on the banks of Swan River in North Fremantle, Perth Saturday. She and her friends were jet skiing when she saw a pod of dolphins. She tried to swim with them, but a shark bit her leg, Fox News reported.

A young man reportedly jumped into the water to retrieve the girl, with many describing him as a hero. One witness suggested that he could be her boyfriend.

According to Daily Mail, the teenager was mauled to death by a bull shark. Bull sharks stick to warmer waters, swim close to shore, and up through rivers into estuaries.

Paramedics rushed to the scene but could not save the girl after she sustained severe injuries on her leg. It was the first fatal attack since Jan. 31, 1923.

Fremantle District Acting Inspector Paul Robinson described the incident as tragic and extremely traumatic. He added that it was unusual for a shark to be that far down the river. They had already issued an alert, warning the people about the shark to inform the public about the incident.

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