Oceans cover 70% of Earth’s surface, and if you think what horrors and marvels the rest of the 30% host, it should come as no surprise that the watery parts of our planet have more than their share of strange stuff as well.
What may surprise you, however, is just how unbelievably weird and mysterious the oceans can get. Here are 10 of our favorite creepy secrets of the sea.
10. Something is eating great white sharks
In 2014, scientists discovered that some strange and no doubt terrifying aquatic creature was snacking on great white sharks, which was worrying because great whites are pretty much the apex predator of the oceans. The phenomenon was discovered off the coast of Southwest Australia where a great white wearing a research tag suddenly dove to 1,903 feet, while the tag (which was later discovered on a beach 2.5 miles from the incident) recorded a temperature spike from 46°F to 78°F. The abrupt plunge and the rising temperature strongly suggested that something had attacked the large shark — but what?
Initially, experts thought that the shark may have been eaten by an even bigger shark, which is pretty creepy already. However, an even more terrifying potential reason eventually emerged: The shark may have been the victim of an orca. Apparently, the killer whales occasionally like to attack great whites. There’s even a documented incident of two orcas attacking a great white and eating its liver, possibly with fava beans and a nice chianti. There’s no consensus on just how common these supposedly rare attacks are, but great whites are certainly aware of them. They appear to be so terrified of orcas that when a pod of killer whales visits a great white’s hunting grounds for just a few hours, the sharks may flee in abject terror and avoid the area for up to a year. Yeah, the ocean is so scary that even great white sharks refuse to go to the rougher neighborhoods.
9. The milky sea effect
It’s one thing to encounter terrifying creatures at sea, and completely another when the sea itself starts acting strange. We’re not talking about huge waves or other weather phenomena, either — we’re talking about a phenomenon where a giant part of the ocean suddenly lights up in an eerie glow. It’s called the milky sea effect, and the areas it affects are so vast that you can sometimes even see them from space In 2005, the phenomenon was captured in photos by the Naval Research Laboratory, and that particular instance spanned a whopping 5,780 square miles — roughly the size of Connecticut.
Oh, and here’s the creepy thing: We have absolutely no idea what’s causing the milky sea effect, how its instances form and what’s the source of the illumination. Right now, the best scientists can do is hazard a guess about huge colonies of bioluminescent bacteria.
8. Devil’s Sea
The Bermuda Triangle may be the go-to area when it comes to strange maritime disappearances and legends of all sorts of paranormal shenanigans. However, the Devil’s Sea in Japan’s corner of the Pacific Ocean can certainly put up a fight. Reportedly, many ships have vanished there, including multiple large vessels in the 1950s. In fact, between 1950 and 1954 alone, no less than nine large freighters reportedly disappeared in the area, and none of them managed to send out a distress call. When the Japanese government got fed up with the situation, they sent a ship called Kaiyo-Maru to research the situation. Reportedly, it disappeared too.
Of course, it must be noted that not everyone attributes these disappearances to sea monsters and aliens, or even believes that there are disproportionate amounts of vanished ships at all. According to Skeptoid, the whole thing is a brainchild of paranormal researcher Ivan T. Sanderson, who invented the Devil’s Sea as part of his theory of “vile vortices,” a set of 10 Bermuda Triangle -like areas with otherworldly attributes. This would cast a number of legends around the area in a rather dubious light — although Skeptoid admits that the disappearance of the Kaiyo-Maru seems to be a legitimate event, so who knows?
7. The Yonaguni “monument”
What would you do if you unexpectedly found a sunken ruin from an ancient civilization? Such a thing happened to marine geologist Masaaki Kimura in 1986, at least if you ask Masaaki Kimura. He was diving off the coast of Japan’s Ryukyu islands when he came across a vast, mysterious rock formation that was so angular and complex that it looked a lot like a man-made structure. Kimura set out to research what became known as the Yonaguni monument, and says that it’s clearly man-made. He also says that there are carvings on some of the structures, and that the “monument” is actually a vast complex that features roads, castles, pyramids and even a stadium. This has led him to conclude that the Yonaguni monument is actually the remains of the Atlantis-like Lost Continent of Mu.
Other scientists disagree, and point out that the rock’s formations are actually perfectly normal for large masses of sandstone in tectonically active underwater areas. However, even if the majority of the structure may not have been built by human hands, pottery from 2500 BCE has been found in the area, so there’s a chance that humans lived in the area before it went underwater, and perhaps even altered the rock formations.
6. The Baltic Sea anomaly
In 2011, the Ocean X shipwreck hunting team led by Peter Lindberg captured a strange sonar image at the bottom of the Baltic Sea. The vaguely Millennium Falcon-shaped object in the picture became known as the Baltic Sea Anomaly, and it soon started attracting all sorts of UFO-themed attention.
Unfortunately for the X-Files-minded, the Anomaly wasn’t a submerged portion of Area 51, or a sign of an ancient civilization. While many experts were initially puzzled by its true nature, even Lindberg himself didn’t truly think it was an alien spacecraft (since they could tell it wasn’t metallic). As such, the reason it caused a big stir was not a “Whoa, aliens” situation, but rather interest over the fact that the Anomaly was so difficult to identify. Well, difficult to people who aren’t geologists — after all, they’re quite certain that the Anomaly is merely a glacial deposit.
5. All sorts of unexplained sounds
The ocean can be a noisy place, and every so often, humanity encounters an underwater sound that’s unlike anything we’ve ever heard. Although the famous “Bloop” sound eventually turned out to be a natural phenomenon known as icequake, there are still plenty of aural underwater oddities to entice and creep out the enquiring mind.
The “Upsweep” is an odd, ongoing constellation of shortish, upsweeping sounds that originate from somewhere in Pacific, and seem to get louder during spring and autumn. No one knows what’s going on, but the prevailing theory is that it has something to do with volcanic activity. “Slow down” is a periodical, gradually slowing seven-minute sound that some people attribute to giant squids, and others insist is just the noise of an iceberg running aground. Then there are individual, unexplained noises such as “Julia” and “The Whistle” — and, of course, the most tragic sound of them all, “52 Hertz.”
52 Hertz is not as mysterious as it is sad, as the sound belongs to a lonesome whale that has a peculiar 52-hertz call that’s much higher than other whale calls, and due to this it’s likely that the animal has never found a mate. Scientists have dubbed it “the loneliest whale in the world,” and have tried to track its location for over two decades, presumably to give it a bro hug and tell it that there are other fish in the sea.
4. The submarine disappearances of 1968
Submarines are dangerous things, so it’s no surprise that every so often, there’s an accident. However, what if four submarines from different countries disappeared in mysterious circumstances within months of each other, and there’s not even a World War raging? This exact thing happened between January and May 1968. The first ship to go was the Israeli INS Dakar, which disappeared in January in the Mediterranean Sea, along with its 69-man crew. Two days after that, the French Minerve and its crew of 52 disappeared on the same region on a routine patrol mission under an experienced captain. After that, things took a turn towards the Cold War: The Soviet nuclear sub K-129 and its 98-man crew went permanently down in Pacific in March, and in May, the equally nuclear USS Scorpion went to the bottom of the North Atlantic sea.
While the sinkings (probably) weren’t the work of a frustrated sea monster who wanted the annoying humans from gentrifying the neighborhood, it doesn’t make the stories behind these four disasters any less interesting. INS Dakar’s wreckage was found in 1999, and while it purportedly just dove deeper than its hull could handle, the denials from the Israeli military and a 2005 interview of an Egyptian naval officer who claims to have sunk the Dakar make its final fate pretty good conspiracy theory material. The reason for Minerve’s loss remains a mystery, but its remains were found in 2019 after an extensive operation.
In 1974, the CIA managed to lift parts of the K-129 in the huge, secretive Project Azorian, which nevertheless leaked to the press within a year, giving birth to the phrase “we can neither confirm and deny” as the Agency was flailing to keep things secret as long as they could. USS Scorpion, on the other hand, remains at the bottom of the sea, its nuclear wreckage no doubt carefully monitored by all parties. We still don’t know whether it was destroyed by a hull breach, an explosion within the submarine, or a Soviet torpedo.
3. The sea serpent sighting of HMS Daedalus
In the “here there be dragons” age of maritime travel when monsters were very much considered an occupational hazard of sailing, one of the more interesting sightings of supposed giant sea serpents came from an account by Captain Peter M’Quhae of HMS Daedalus, a British vessel that purportedly encountered such a monster on August 6, 1848. In an official report to the Admiralty, the captain described a huge, serpentine creature with a large head and “at the very least” 60 feet of unseen body that it used to propel itself forward.
To this day, the story remains one of the more enticing accounts of monstrous sea creatures thanks to the general perceived trustworthiness of Royal Navy officers, and their unlikeliness to fabricate such sightings. Still, even at the time, some biologists pointed out that the good captain and his officers had probably just seen an elephant seal and gotten confused.
2. The vanishing island of Bermeja
Off the Yucatan peninsula, there used to be a tiny, uninhabited island called Bermeja. We say “used to,” because at some point, the island disappeared. For centuries, it used to feature on the area’s maps, but by the time the 18th Century rolled in, it slowly started to fade away from cartography, and its last confirmed appearance in a map was in 1921. Mexico has been quite keen to know what happened to their tiny island, and in 2009 alone there were three attempts to locate it with cutting edge technology, all to no avail.
There seems to be two main theories regarding Bermeja’s relatively sudden disappearance. One is that the low-lying island sank because of rising sea levels or an island-sinking natural disaster. The other is that, uh, the CIA blew up the island because the area contained oil and they wanted to improve the U.S. claim on it. However, there’s a third, arguably even stranger possibility: That Bermeja never existed. Early explorers sometimes drew maps with inaccuracies that only they knew about, so their competitors could not rely on them. Bermeja might be such an inaccuracy that at some point went viral among the cartographers, only to eventually fall into obscurity when everyone started making accurate maps. Mexico, however, claims to have information that Bermeja existed, though not in the location the maps show… so it appears the jury is still out on the “phantom island” and its true nature.
1. The immortal jellyfish
What’s the most mysterious creature of the sea? Most people would probably say it’s the giant squid, or one of the many cryptozoological monsters that supposedly roam the oceans. However, a tiny jellyfish known as Turritopsis dohrnii leaves all them in shame, for reasons best described by its nickname: The immortal jellyfish.
The immortal jellyfish is exactly what it says on the tin: It can live forever. T. dohrnii can alternate between polyp and medusa states, and whenever it is injured or comes to the apparent end of its natural life, it just turns its old and damaged cells back to young, virile ones and goes right on. It basically has the healing powers of Wolverine and can reverse-age like Benjamin Button, only at will.
This ability to basically reset itself and start with a full health bar whenever death comes knocking makes Turritopsis dohrnii one of the most incredible instances of marine life, and if science can ever learn to harness its powers… well, let’s just say we’d all save a lot on hospital bills.