Sharks are among a group of animals with a 6th sense that humans don’t have – they use Earth’s magnetic field to navigate

bonnetheads sharks
Bryan Keller holding a bonnethead shark.

Shark species have an uncanny ability to find their way back to the same feeding grounds every year – even areas thousands of miles away.

According to a study published Thursday, that’s because sharks have a superior navigational tool at their disposal: They can orient themselves using Earth’s magnetic field.

They’re far from the only animals to do so. Birds, whales, and many other species use the same sixth sense to plot their migrations.

Bryan Keller, a biologist at Florida State University who co-authored the new study, likens this sense to “having an ‘internal GPS.'”

“This is, in my opinion, the best explanation for how migratory sharks successfully navigate during long-distance movements,” Keller told Insider.

‘Sharks garner map-like information from the magnetic field’

Earth's Magnetic Field
An illustration of Earth’s magnetic field.

Nearly 2,000 miles below Earth’s surface, swirling iron in the planet’s outer core conducts electricity that generates a magnetic field. This field stretches all the way from the planet’s interior to the space surrounding the Earth. It’s what protects the world from deadly solar radiation.

But the direction that the electromagnetic energy flows, as well as the strength of the resulting protective sheath, depends on where on the planet’s surface you are. So animals that use the magnetic field to orient themselves do so by detecting these differences in field strength and flow. They then use that information to figure out where they are and where to go.

Scientists long suspected sharks could navigate using the field, since the animals can sense electromagnetic fields in general. But that hypothesis had been difficult to confirm until Keller’s study.

His team examined the bonnethead shark, known as Sphyrna tiburo, because the species exhibits site fidelity – meaning it returns to the same estuary habitats each season.

“This means the sharks have the capability to remember a specific location and to navigate back to it,” he said.

bonnetheads sharks
An overhead shot of bonnethead sharks in a holding tank.

The team captured 20 bonnetheads off the coast of Florida in the Gulf of Mexico, then placed the sharks in a 10-by-10-foot tank. They generated a tiny magnetic field within a 3-square-foot area of that tank. (Bonnetheads only reach 4 feet in length, which made them an ideal species to study in such a small pool, Keller said.)

The team then tweaked that localized magnetic field to mimic the electromagnetic conditions of various locations hundreds of miles away from where they’d caught the sharks. If the animals were truly relying on magnetic-field cues to navigate, the thinking went, then the bonnetheads would try to reorient themselves and start swimming in the direction they thought would lead to the Florida coast. That’s exactly what happened.

When the researchers mimicked the conditions of the magnetic field on Florida’s Gulf Coast, the animals exhibited no preference in which direction they were swimming – suggesting they assumed they were already in the right place.

“I’m not surprised that sharks garner map-like information from the magnetic field, because it makes perfect sense,” Keller said.

Many animals use the magnetic field for navigation

Even though the new study was done on bonnetheads, Keller said the findings likely apply to other shark species as well.

Great White Shark
A great white shark heads near the Neptune Islands, Australia, in June 2014.

How else could a great white, for example, migrate from South Africa to Australia – a distance of more than 12,400 miles – then return to the exact same chunk of ocean nine months later?

“En route to Australia, the animal exhibited an incredibly straight swimming trajectory,” Keller said of great whites. “Given that the magnetic field is perhaps the only constant and ubiquitous cue available to these migratory sharks, it is sensible that magnetic-based navigation is responsible for facilitating these incredible navigational successes.”

Other navigational cues do exist, including currents and tides, but Keller said the magnetic field “is likely more useful than these other aids because it remains relatively constant.”

Biologists still aren’t sure how sharks detect the field, but a 2017 study suggested that the animals’ magnetic receptors are probably located in their noses.

The ability to detect and orient using the magnetic field is fairly common in the animal kingdom overall, according to Keller. Scientists have observed that type of behavior in bacteria, algae, mud snails, lobsters, eels, stingrays, honey bees, mole rats, newts, birds, fish like tuna and salmon, dolphins, and whales.

Sea turtles, too, rely on magnetic cues when they migrate thousands of miles to lay eggs on the same beaches where they hatched.

Two_Wire_Fox_Terriers
Two wire-haired Fox Terriers.

Dogs, meanwhile, can find their way home both using their impressive sense of smell and by orienting themselves using the magnetic field, according to a June study.

“The magnetic field may provide dogs with a ‘universal’ reference frame, which is essential for long-distance navigation,” that study said.

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Video shows sailors fighting off a pod of killer whales with poles and flares after they break boat’s rudder

killer_whale_attack_final
A pod of killer whales surround the vessel Serena IV in the waters of the Gibraltar Strait, on April 3, 2021.

  • A video shows the moment sailors on a boat in the Strait of Gibraltar fought off a pod of orcas.
  • Crew members desperately tried to scare the giant whales away but were still left without a rudder.
  • An expert told Insider that while these incidents have been going on since 2020, they’ve got less intense.
  • See more stories on Insider’s business page.

A new video shows the moment sailors aboard a ship in the Straits of Gibraltar fought off a pod of killer whales with poles and flare lights after the giant sea creatures broke off part of the vessel’s rudder.

The incident happened on April 3 off Morocco’s coast of Cape Spartel, when the pod approached the Serena IV sailboat and started ramming its rudder.

The captain of the boat, Antonio Busse, told Real Press that he had been on watch duty that evening when he heard an unfamiliar noise and rushed to the back of the ship, witnessing what he counted to be four orcas.

Read more: These 17 Gen Z climate activists are ready to challenge Biden and their lawmakers to act fast on one of the most urgent crises of their time

In the dramatic video footage published by the DailyMail, Busse can be seen using a long pole to hit the side of the boat as well as the water in an attempt to scare the orcas away.

Meanwhile, other crew members are seen desperately throwing items into the water and shouting at the whales, telling them to “get off the boat.”

At one point, the sailor filming the video can be heard shouting: “Look, they hit the wheel a bit! They don’t like the wheel, they always go for the wheel.” The orcas eventually broke off part of the vessel’s rudder.

One crew member eventually lights a red flare and throws it in the water, prompting the whales to swim away.

Despite a partially broken rudder, the boat managed to continue on its journey and anchor in the Spanish port of Tarifa.

Watch the video below:

Busse, who has sailed across the world, said that the incident had been very scary, adding that “something like this had never happened before” in his lifetime, according to the DailyMail.

“I have been in Antarctica and I have never seen something like this,” he said.

The incident is not the first of its kind in the area. In September 2020, the Observer reported that killer whales had been causing damage to more than a dozen boats in the Straits of Gibraltar, in some instances even leaving crew members seriously injured.

Researchers told the Observer that it was not unusual for orcas, which are highly social and curious animals, to follow boats or even playfully interact with them and that ramming the rudder is not unheard of.

However, many were still left scratching their heads as to why some of the incidents were aggressive in nature.

Ruth Esteban, the head of international relations for the Orca Atlantica Working Group, who studies these orcas, told Insider that since last year the interactions have still been happening, but they’ve “not been as intense.” This is partly also because of the season, she added.

The last interaction was on April 1, Esteban said, adding that there has been a lot of activity in the Strait of Gibraltar area.

“We don’t like to call them attacks because it comes across as more playful. We still don’t fully know why they do this but from watching videos of the different interactions, it is obvious they behave differently depending on the speed of the boat or the type of boat,” said Esteban. “When we watch these videos, for us, it doesn’t look like they’re ‘attacks.'”

Esteban also added that although the orcas had scared crew members on ships, they had not yet posed a significant danger to humans.

Wild killer whales have never fatally attacked humans in the ocean. However, there have been cases of captive orcas killing or injuring handlers at marine theme parks.

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Sperm whales taught each other how to avoid hunters’ harpoons 200 years ago, according to new study

Sperm Whales
A pod of sperm whales swimming underwater.

  • Sperm whales taught each other how to avoid harpoons 200 years ago, according to a new study.
  • It was based on newly digitized logbooks from hunters in the North Pacific in the 19th century.
  • The paper concluded that the decline in harpoon strike rates was due to whales communicating with each other.
  • See more stories on Insider’s business page.

Sperm whales taught each other how to avoid harpoons after hunting for them began 200 years ago, according to a new study.

Published by the Royal Society on Wednesday, the research was based on newly digitized logbooks from American whalers, which recorded details of their expeditions in the North Pacific during the 19th century, such as the number of whales spotted or harpooned.

Although they were in high demand for their whalebone, ivory, and blubber and almost 80,000 ‘voyage days’ recorded, there were only 2,405 successful whale sightings, a mere 3% success rate.

The study’s authors, cetacean researchers Professor Hal Whitehead and Dr. Luke Rendell, as well as data scientist Dr. Tim D Smith, also found that the strike rate of the whalers’ harpoons fell by 58% in less than two and half years after they first began hunting in the region.

In Halifax, Canada, Professor Whitehead of Dalhousie University told The Owen Sun Sound Times: “That was very remarkable. I thought there might be a drop, but not that much and not that quickly.

“Usually, you expect it to increase as they figure out stuff and become more successful. That’s typically how our exploitation of wildlife goes. We become more efficient as we learn how to do it.”

The study concluded that sperm whales had learned how they were being killed, shared this information with their pod and changed their behavior accordingly, displaying ‘cultural evolution.’

The species live with their children in female-only pods or groups, allowing them to form close links and share tips to evade hunters.

The hunters recognized the sperm whales had developed tactics to evade them. Instead of forming defensive squares used to fight off their natural predators, the killer whale, the sperm whales, understood that swimming against the wind would allow them to outrun the wind-powered hunters’ ships.

The advent of steam power and grenade harpoons in the later years of the 19th century meant even the canny sperm whale was doomed to mass slaughter, however.

‘This was cultural evolution, much too fast for genetic evolution,’ says Whitehead.

Sperm whales have the largest brain of any animal on the planet and the researchers highlighted that if they were able to adapt 200 years ago, they could probably also face the ocean’s challenges today.

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