Hundreds of hammerhead sharks gather around an ancient volcano in the Pacific Ocean, drawn by cryptic signals emanating from the seabed, a new clip reveals.
Footage featured in the third episode of Netflix's new wildlife documentary series „Our Living World” shows a school of hammerhead sharks (Spirnidae) Cocos Island – A volcanic island in the eastern tropical Pacific about 310 miles (500 kilometers) southwest of mainland Costa Rica.
Cocos Island is known as a haven for endangered hammerhead sharks, but scientists still aren't sure how and why so many sharks cross the ocean to congregate there each year.
„We don't know how these sharks do it,” Ben Roy, series producer for Our Living World, told Live Science. „We know that they have sensors on their heads, and we know that these sensors pick up the magnetic signature of these cold volcanic rocks.”
The island was formed when lava from an ancient underwater volcano erupted and solidified until it eventually rose 12,000 feet (3,660 meters) above sea level.
In the episode, the crew follows a young female hammerhead shark who instinctively knows her way to Cocos Island thanks to electromagnetic signals emanating from the hard volcanic rocks on the island's slopes.
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In the clip, the young female joins hundreds of other hammerhead sharks as they form a vortex around the island. „In the real moment, when all those hammerheads come together and start swimming in those eddies,” Roy said his team „got lucky with some cracking behavior.”
This isn't the first time sharks have mysteriously congregated. Scientists previously documented A Hammerhead shark swarm In the tropical waters of French Polynesia, in the South Pacific Ocean, but the crowd attracted only females.
Our living world
The hammerhead shark collection is one of many featured in the four-part nature series premiering Wednesday (April 17) on Netflix. The show highlights the complex connections that support the largest web of life on Earth, from the invisible fungal networks that nurture forest ecosystems to the Atlantic clouds of nutrients that blow from Africa to South America and rain in the Amazon.
„What really sets this series apart from anything I've been involved with or seen in wildlife shows on TV is the connections, because what we've tried to do is tell a story about individual animals and what animals look like. Behaviors are connected to a much bigger picture,” said Roy.
In telling these stories, Roy said, „we were really looking for the aha.” „We could be the first generation to fully understand the connection to what's going on here, and potentially the last generation to put that knowledge to good use.”
The Hammerhead Shark assembly scenes meet every expectation Roy had for the show, he said. „Talking about those 'wow' expressions — for me that was one of them,” he said. „Do sharks need volcanoes? Who knows!”