15 Sea Creatures That Have Left Scientists Completely Baffled

According to the National Oceanic and Atmospheric Association in the US, we have explored less than five percent of the ocean floor. We're better acquainted with the Moon and Mars than we are our own

According to the National Oceanic and Atmospheric Association in the US, we have explored less than five percent of the ocean floor. We're better acquainted with the Moon and Mars than we are our own waters, so it's little wonder that the underwater world is home to some pretty complex and surreal-looking creatures.

In waters less explored, sea life can take on a pretty magical and sometimes scary form, boasting some wonderfully weird features and even odder behaviour - so it's no surprise that this lot have been the subject of utter fascination for many of the world's leading marine experts.

Every marine species has its surprises, but many of these guys have held on to their secrets for years, sometimes decades. From fish with light fixtures on their heads and living fossils to a creepy dolphin and bird hybrid, this bizarre collection of marine life has left the world's top biologists scratching their heads (and have left science-fiction writers with a ton of inspiration!). Here's a rundown of the 15 most mysterious sea creatures to date.

15 'Purple Sock' Creature


You know the classic fishing cliché of finding an old boot when you were hoping and praying for an exciting catch? More than 60 years ago, a group of Swedish biologists had the reverse kind of luck when they came across what appeared to be an old sock and was in fact, a worm-like sea creature. What they weren't so lucky with was the fact that they weren't able to pinpoint the how's, why's and what's of this odd sea worm for another six decades.

Fortunately, the sea worm forever known as the deep sea 'Purple Sock' (owing to its uncanny resemblance to a lonely sock discarded on the sea bed) has finally had some light shed on its curious appearance and even which family tree it may have belonged to.

Previously, only one species of Purple Sock had been discovered, but earlier this year, research scientists in Australia and the US found four new species, which led lead investigator from the San Diego Institute of Oceanography, Greg Rouse, to some interesting and detailed conclusions about the creature. He observed that they have no brains, eyes or guts. The simply feature a wide mouth that allows them to both take in food and excrete it. Nasty. For the sake of science, though, we're glad this funny sock worm is no longer lost at the bottom of the ocean laundry hamper.

14 Gulper Eel

Via National Geographic

As its name suggests, this isn't your average streamlined eel. The gulper eel is similar to the common eel in terms of length, but that's where the comparison ends. It has a gigantic mouth in proportion to its body and this helps it to gulp down prey almost twice its own size. Despite being blessed with this abnormally large mouth, however, the gulper eel doesn't exactly live up to its intimidating name, since it usually only feeds on seaweed and small crustaceans.

As it reaches maturity, the male gulper eel's teeth and jaws degenerate and it becomes more content to find a mate than it does to scout out food. A romantic, yet sad fact, since  gulper eels usually die after reproduction.

Inhabiting depths of around 3000 to 26,200 feet, the gulper eel has been difficult for marine experts to locate and attempt to make sense of its seemingly unnecessary jaw size. Gulper eels could perhaps be a throwback to pre-historic eel species that may have needed larger mouths to hunt larger prey and attack even larger enemies.

13 Angler Fish


Angler fish are instantly recognisable as the main mascots of the deep. The distinctive luminous lure hanging from the head of the female Angler Fish is both its Sat Nav device for finding its way in the dark and its means of drawing prey nearer to its enormous, piranha-like mouth.

But despite their iconic appearance, science hasn't many clues about the angler fish. They live in complete darkness over a mile below the surface of the water, in the most cold and unfriendly parts of the ocean floor.

The bizarre mating habits of angler fish have been the main subject of fascination for scientists, since 19th century sea experts had only the females to work with. It took until 1924, in a discovery made by Charles Tate Regan at the Natural History Museum, to reveal that a smaller fish was attached to the female’s belly by their snouts. But these weren't the offspring of the female angler fish - they were her mate. The female hunts while the male lies dormant and depends on her for nutrition. Quite the gender role reversal!

12 Giant Squid


There was a time when this colossal sea creature was rarely found anywhere other than in stories written by Jules Verne and HP Lovecraft. Fast forward to the 21st century and Giant Squid still largely remains a mystery, with 2004 marking the first date that one had ever been photographed in the wild. With frequent sightings of the Giant Squid washed up on beaches in Spain and New Zealand, this has helped reveal clues as to the maximum size of this monster of the deep - ranging between 5 and a whopping 55 metres in length!

Thankfully, Giant Squid of the latter measurement have yet to wash up on beaches or terrorize submarines any time soon. In 2013, however, a team of scientists in Japan got closer than most to the elusive sea beast, managing to capture astonishing first-time footage of a 30-foot long Giant Squid in its natural habitat. Marine biologist Edie Widder, who captured the world-record footage, noted its 'beautiful silvery gold color' and a colleague added that it was missing two of its largest tentacles. Hopefully, this discovery can help unlock further mysteries about the Giant Squid before its main predator, the Sperm Whale, renders it extinct.

11 Deep Sea Mushroom

Via National Geographic

To the untrained eye, these sea creatures might seem to resemble run of the mill wild mushrooms that you might find in the woodlands, but these deep water fungi may actually hold the key to our understanding of how all animal forms may have evolved. No, really.

First spotted in 1986 just off the Australian coast, these bizarre mushroom-shaped animals have been puzzling scientists ever since. Found in waters 3,500 feet deep, it was discovered that the creatures were so strongly preserved in ethanol and formaldehyde that any attempt to run genetic testing fell as flat as their caps.

Thankfully, recent research by scientists at Cambridge and the University of Florida has at long last been able to paint a clearer picture of their evolutionary origins. The sea mushrooms are said to share very similar traits with those of long-extinct species that date back to the earliest branch of animal life, sporting simplistic features for survival, such as their small mouth at the base of their 'stalk' and a digestive system seen in the opaque portion of the body.

10 'Hallucigenia'


This is a fairly aptly named sea creature, since you could be forgiven for thinking this spike-covered critter could only exist in a sci-fi horror film. This tiny 2cm-long worm-like critter lived 500 million years ago and has confused scientists for the best part of a century - chiefly because, when the fossil was first formally described by scientists, it was the wrong way up. Oops.

What would scientific discovery be without a little trial and error though, right? Scientists at the University of Toronto were only recently able to confirm which side of the Hallucigenia was its back and which were its feet. There has also been much confusion as to which end was the creature's head and which was the tail. Piecing this pre-historic sea worm together has been quite the puzzle, but recent fossil studies in Canada have helped bring the full creature to light.

Scientists in Burgess Shale, Canada were chipping away at the fossil, when they discovered a spoon-shaped head with eyes and a slightly cheeky smile. Dr. Martin Smith at the University of Cambridge commented that "it's as if the fossil was grinning about the secrets it had been hiding." Further studies could help provide an evolutionary link to today's velvet worms.

9 Frilled Shark


This creepy ocean-dweller, measuring between 4.5 and 6 feet in length, is often referred to as a 'living fossil', since its appearance has barely changed since prehistoric times. It has also been likened to a giant eel and is thought to move about in the water much like a snake does - making it the subject of fascination for marine biologists and the subject of nightmares for...everyone.

Thankfully, it is typically only found in depths further than 600 feet, so the chances of seeing it in the flesh are pretty slim. For this reason, the Frilled Shark has been hard to track down and analyze, having only been filmed in its natural habitat as recently as 2004 by NOAA scientists during a submersible dive in the Atlantic. A female Frilled Shark was also captured by Japanese fisherman in 2007.

This living dinosaur of the sea owes its name to the bizarre gills that fan out across its throat, compared with the smaller, separate gills that most sharks have. Its 25 rows of teeth (300 in total) are also frilled out in little spikes for grasping and sinking into its unfortunate prey. With its dead eyes, terrifying teeth and snake-like body, this shark may be the closest thing there is to a real sea serpent.

8 Stargazer

Don't be fooled by its seemingly soft and romantic name. Stargazer fish are calculating predators and far stealthier than they look. With its face positioned on the top of its head, Stargazer fish are constantly alert to overhead prey and choose to camouflage themselves in the sea bed to pounce on unsuspecting food.

Even if they aren't fast enough to catch their prey, Stargazers are poisonous and can even stun prey with electric shocks. Not a bad hunting technique for something that resembles an angry flatfish. Stargazer fish have been found in Indonesia, Canada and parts of the US.

Some species have even been discovered with a lure protruding from their mouths, presumably to further aid them in attracting prey. The very fact that some species of Stargazer have this hunting advantage and others don't has puzzled scientists to this day.

7 Prehistoric-looking 'Mutant Dolphin'


This disturbingly recent sea life discovery is the stuff of nightmares - partly because of its size and partly because the mismatch of species going on makes it look like the kind of monster your parents invented to scare you into eating your vegetables. Being described by marine experts the world over as a prehistoric-like mutant, this unsettling creature was found washed up on a remote beach on the East Coast of Russia earlier last year.

The carcass of this fascinating creature has been most closely identified as a species of 'big dolphin' by biologists at the Sakhalin Research Institute of Fisheries and Oceanography. But the unusual appearance of fur and a bird-like beak on this so-called dolphin have left many sea life experts stumped.

Speculation on social media has invited some apt and humorous conclusions as to what this bizarre dolphin bird hybrid could be. Some people have made fictional comparisons to the creature, with many likening it to the Loch Ness monster and some even suggesting it shares similarities with Big Bird from sesame street. Whatever it reminds you of, it's not nice to imagine it swimming near your shores!

6 Napoleon Wrasse

This rare and incredibly curious species has so many unique features that it's hard to know where to begin. Sometimes known as the Maori Wrasse or the Humphead Wrasse, the design alone of these remarkable fish will leave you open-mouthed like the proverbial guppy. First off, the beautifully intricate markings on its skin, likened to the New Zealand Maori war paint, are actually unique to each individual Wrasse, like fingerprints or snowflakes.

What's more, the Wrasse species are protogynous hermaphrodites - meaning they can alter their sex. Though formally discovered in the mid 19th century, the Napoleon Wrasse could have many more surprises in store. Sadly, this intriguing creature could face extinction due to the destructive international fishing trade. Let's hope for the sake of scientific discovery that the Napoleon Wrasse can be preserved for as long as possible.

5 Barreleye Fish


By the sounds of a Barreleye Fish, you could make the assumption that they have the eyesight strength of an owl and similarly large eyeballs. Actually, the reverse is true, they're blind. Fortunately, their uniquely transparent heads let a lot of light in, helping them find their way through the dark ocean depths (typically inhabiting waters between 2,000 and 2,600 feet deep).

The name refers to their tubular-shaped eyes that face upwards to collect as much light as possible, as well as help them look for any food swimming overhead. You only need to look at these intriguing specimens to understand why marine scientists are so bewitched by them.

The Barreleye fish's ability to rotate its large eyes helps it to avoid the path of predators, even in the process of looking for food overhead - and remarkably, this is all done by collecting light in its transparent dome-shaped head. A blind fish with its eyes on everything. If marine biologists are confused, we certainly are too!

4 Megamouth Shark


Sharks are pretty terrifying in general, so it's very unsettling to discover one with a gigantic mouth, or 'Mega Mouth' as it has been aptly christened. Up until 1976, this big-mouthed beast was relatively unknown to science (a year after the release of Jaws, incidentally. Coincidence?). When the crew of a US Navy ship in Hawaii deployed two large parachutes as anchors, they weren’t prepared for what they found entangled in them once they were hauled back up again.

The 14.6 foot shark was later taken to an aquarium in Hawaii, whereupon Ichthyologist Leighton Taylor named it Megachasma pelagios which roughly translates as "huge yawning cavern of the open sea." Cute.

A little before the 1976 discovery of the mega mouth shark in its full form, megamouth shark teeth were actually discovered by scientists in the 1960s, but were soon shelved since the lack of technology couldn’t help them identify the source. Decades on from both discoveries, scientists are still trying to figure out how this windsock-mouthed shark operates.

3 Blanket Octopus


The Blanket Octopus or Tremoctopus is one amazing sea creature and, as its name suggests, resembles a pretty patterned blanket floating through the water. Where an array of tentacles would otherwise hang down separately from its body, a beautiful fleshy cape trails after it. But don't be fooled by its graceful appearance - they're pretty badass.

Very little is known about its biology, but what is known about this amazing creature is mind-boggling. For starters, the female blanket octopi (which can grow up to 2 metres in length) can happily detach its blanket from its body if threatened. What's more, when threatened with the venomous sting of a deadly Portuguese man o' war jellyfish, the female octopus is immune to their poison and elegantly wades in to rip the jellies tentacles clean off and keeps them to use as fleshy whips. The sea hath no fury like a female blanket octopus scorned!

However, it isn't just their means of self-defence that sets this creature apart from other Octopi and most other sea creatures. While the female blanket octopus reaches up to 2 metres long, the male in comparison is barely bigger than the size of a walnut! Just what other revelations could this amazing creature be holding on to?

2 Goblin Shark


The Goblin Shark isn't just named so because of its long, protruding snout and snaggletoothed grin. It is also in possession of a menacing ability that wouldn't put it out of place in a children's fairy tale. When it comes to catching its prey, this villainous looking shark can suddenly extend its jaws outwards and move them independently from its body to latch on to unsuspecting fish.

The Goblin Shark's feeding habits are what really show off the creature's incredible protruding jaw in action. Its jaw quickly unleashes on to enemies, in a way that is almost reminiscent of the second mouth that comes snapping forth from the jaws of the titular creature in Alien.

Found mostly in the waters of Japan around 1,200 metres below the water's surface, scientists have had a hard time getting close to this strange species of shark. But, considering its ninja-like hunting abilities, this is probably a good thing.

1 Glowing UFO Jellyfish


As we head closer towards Christmas, you may be thinking that this is an image of the latest gadget for kids. Is it a yo-yo? Is it a spaceship? Is it a remote controlled robot spider? It's sadly none of those, but it's real alright and it lives in the deepest parts of the ocean, near the Mariana Trench (about 12,000 feet). This beautiful and intriguing sea creature is an exciting example of how much we have left to discover about the deepest and darkest corners of the ocean.

This astonishing UFO jellyfish, as some have referred to it as, lives in waters where no light reaches, making its glowing, firework-like body all the more impressive. NOAA scientists on board the Okeanos Explore Vessel grabbed amazing footage of the beguiling sea creature in April this year and have now classified it as a hydromedusa, due to its long spaghetti-like tentacles. Since the video footage went viral, many have taken to social media to classify the creature for themselves - comparing it to an alien, a deep sea firefly and even a Tim Burton character! However you characterise it, this sea creature is incredibly hypnotising and we kind of envy the experts being paid to ponder its existence. Go Google it - it's amazing!


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15 Sea Creatures That Have Left Scientists Completely Baffled