The ocean is shrouded in mystery. It covers about 71% of the Earth’s surface, yet we know very little about it when you consider how vast it is. In fact, it is estimated that at least 80% of the ocean has never been mapped, explored or seen by any humans. So what is lurking out there? We’ll never know everything, but one online group is dedicated to featuring all of the creepy, beautiful and fascinating creatures that are living deep down in the sea.

Let me introduce you to The Depths Below subreddit. With the tagline, “Because we all know there’s things lurking underwater”, this group shares rarely seen footage and photos of sea creatures that you might not even know exist. We’ve gathered some of their most captivating posts down below, so if you already have a fear of the ocean, tread lightly. But if you’re intrigued by the mysteries and depth of these great bodies of water, we think you will have a blast exploring this list. Be sure to upvote all of the creatures that you find most interesting, and then let us know in the comments if you have ever seen any peculiar animals while at the beach. Keep reading to also find an interview with Bart Vanhoorne of the World Register of Marine Species, and then if you’re looking for another Bored Panda piece highlighting how vast and mystifying the ocean is, check out this story next.

#1 Leaf Sheep, The Adorable, Photosynthesizing Sea Slugs

Image credits: quinnstonking

There’s nothing better than a trip to the beach. Getting to lay out in the sand soaking up the warmth of the sun and then jumping into the cool waves when you start to overheat is the best. The fresh scent of sea air and the sand between your toes make the experience feel so special, and if you’re lucky, you might even spot a sea dollar, a crab or a dolphin off in the distance. Occasionally, a jellyfish might catch you, but it’s rare that a beach trip includes very many encounters with other wildlife. If you go just a bit further into the ocean though, or a lot further, there’s no telling what you would find.

Much of what we know about the ocean is actually just estimations. It is so large and so vast that it’s difficult to even comprehend. By using satellite measurements, scientists have estimated that the average depth of ocean basins is 3,682 meters or 12,080 feet. That is almost as tall as Mount Fuji, so just imagine the famous volcano flipped upside down. That’s the bottom of the ocean, on average.  

#2 Great Googly Moogly

Image credits: KingNeptune767

#3 It’s Not All Bad Down There

Image credits: reddit.com

According to the Intergovernmental Oceanographic Commission, satellite data has also been used to create high-resolution seafloor mapping, but only 10% of the ocean’s floor has been mapped in high resolution. So for the most part, it is still a mystery to us. In fact, scientists know more about the surface of the Moon and about Mars than we do about the depths of the ocean. For all we know, there could be aliens hiding down there!

The Pacific Ocean in particular is extremely mysterious, as it is the largest and deepest ocean basin in the world. It covers almost a third of the planet and almost half of the water surface. The Pacific Ocean’s average depth is a staggering 4,280 meters (or 14,040 feet), which is about the height of Mount Whitney in California. The deepest known spot on the planet is actually part of the Pacific Ocean as well, Challenger Deep in the Mariana Trench. East of the Philippines, this trench is more than 1,500 miles long and 43 miles wide, and it’s deepest spot reaches 11,034 m (or 36,201 feet) below sea level. That’s over 2 kilometers deeper than the height of Mount Everest. 

#4 The Cutest Shark Attack Ever

Image credits: SYLOH

#5 Meet “Inspector Clouseau”, The World’s Only Pink Manta Ray

Image credits: Peachy-Persimmons

#6 Meet This 90 Year Old Turtle!⁠

Image credits: Ghada0_Ahmed

The Atlantic Ocean is the next largest ocean after the Pacific, covering about a fifth of the Earth’s surface. There is a mountain range hiding in the Atlantic called the Mid-Atlantic Ridge that has been seen with satellite imagery. It is the longest mountain range in the world, coming in at a whopping four times the length of any other prominent mountain range, including the Andes and the Himalayas. The Atlantic Ocean basin is also growing every year by about 5 centimeters due to volcanic activity in the Mid-Atlantic Ridge. This is also causing the Pacific Ocean to shrink by a few centimeters annually.

The Indian Ocean is the third largest ocean, with a surface area that is about 5.5 times the size of the United States. Most of the Indian Ocean is about 5000 meters deep, but it also features the Java or Sunda Trench, which reaches 7,450 meters (or 24,442 feet) below sea level. The Intergovernmental Oceanographic Commission also notes that, “Waters in the Indian Ocean basin have one of the lowest oxygen content of the world owing to greater evaporation rate in this ocean than its run off or precipitation influx. This makes life growth in the Indian Ocean basin rather unique.”

#7 A Scallop That Looks Absolutely Monstrous. The Blue Parts Are Its Eyes, And It Can Have Over 200 Of Them

Image credits: Peachy-Persimmons

#8 Okey, I Have To Admit This Is Almost Cute… Almost

Image credits: Nidhoggking

#9 A Terrifying Comparison Of The Tentacles Of The Giant Squid (Left) And Colossal Squid (Right). The Giant Squid Is Meant For Painful Latching While The Colossal Squid Is Meant For Ripping Apart

Image credits: Peachy-Persimmons

The Arctic Ocean is the world’s smallest, coldest and shallowest ocean. It used to be completely covered in ice year round, but unfortunately, due to climate change, that is no longer the case. Due to the freezing temperatures, this ocean also houses less sea life than its counterparts. The Arctic also has the lowest salinity level of any ocean, due to the large amount of freshwater flowing into it and its low evaporation rate. But this small ocean causes currents for the entire globe, as the more of its ice that melts, the higher sea levels can rise worldwide.

The Southern Ocean is the second smallest ocean, as it covers about one sixteenth of the total ocean area. In fact, this ocean was only recently recognized by the International Hydrographic Organization in 2000, because it encircles Antarctica and is composed of parts of the Atlantic, Indian, and Pacific Ocean basins. This small ocean has plenty of deep water though, as its average depth is 3,270 meters and its deepest point reaches 7,433 meters. Combined, Antarctica and the Southern Ocean contain about 90% of the planet’s ice.

#10 Sitting On The Edge Of The Abyss

Image credits: 5_Frog_Margin

The ocean is mysterious enough in and of itself, but the countless creatures hiding inside of it are even more perplexing. According to the World Register of Marine Species, or WoRMS, there are currently 240,874 accepted marine species. However, their database only has images for 38,055 of these creatures. Their website explains that, “The aim of a World Register of Marine Species is to provide an authoritative and comprehensive list of names of marine organisms, including information on synonymy.” The gallery on WoRMS includes many different categories of creatures, including Fungi, Aves (birds), Scyphozoa (jellyfish), Plantae, Crustacea, Nematoda, Reptilia and many more. The database can be overwhelming due to the sheer number of images and species it catalogs, but it is amazing to know that this is only a small portion of what’s actually out there lurking in the depths.    

#11 The ‘Strawberry Squid’ Lives In A Region Of The Ocean Known As The Mesopelagic Or “Twilight” Zone, 200 To 1000 Meters Below The Surface [photo By Paul Caiger]

Image credits: cas2ie

#12 Sea Slugs Be Lookin Like They’re Straight Out Of Ark Or Subnautica

Image credits: masquite

We reached out to Bart Vanhoorne, a member of the WoRMS Data Management Team, to hear how much we really know about marine life. Bart told us, “Less than [we know about] the moon, so we don’t know a lot.” But he noted that they are learning more each and every day. We also asked him how a new marine species is found and classified. “They are found by taking samples from the sea and comparing the species with existing descriptions. If they cannot be compared to anything known, it’s considered a new species and described in a scientific paper,” Bart explained. “New DNA techniques are also being used for this. They are classified in a taxonomy/hierarchy.”

Lastly, we asked Bart what we should all know about marine life and why we should care about it. He reiterated that even scientists know very little. “Only 10-20% of the sea in general is known to science.” But when it comes to why we should all be interested, he stated, “It should be researched before it’s lost.”

If you’d like to learn more about marine life from WoRMs, you can check out their website right here.

#13 Sleeping Sperm Whales

Image credits: KevlarYarmulke

#14 Picture Of A Leopard Seal Taken In The Dark Depths. Its Only Natural Predator Is The Killer Whale

Image credits: esbohigatns

#15 Amazon River Dolphins

Image credits: Neon_Jam

The Depths Below subreddit is famous for sharing videos and photos of creatures many of us have never seen before or even heard of, and it’s clearly grabbed the attention of many people, as the page has amassed over 800k members over the past 9 years. The community’s description states, “71% of the earth’s surface is covered by water according to NOAA. That only gives us 29% where we’re safe. If an animal the size of a blue whale can disappear for months at a time, what else is down there? We’re here to show you.” And they certainly do. Scrolling through the page for a few minutes, you’ll find deep sea footage of animals that look like aliens and fish that look like they might bite off your head if they had the chance. But along with all of these fascinating images, we wanted to learn a bit about the creatures as well. So we consulted Marine Madness’ list of mind blowing facts about our oceans and marine life.  

#16 Hatchet Fish Faces Looking Like The Souls Of The Damned

Image credits: Peachy-Persimmons

#17 Giant Sturgeon In The Fraser River, Canada

Image credits: hecticaesthetic

#18 The Size Difference Between An Adult Sunfish And A Sunfish Fry

Image credits: Peachy-Persimmons

Did you know that Greenland sharks can live for up to 500 years? The National Ocean Service reports that these creatures have the longest lifespans of any vertebrates. Greenland sharks have no fin spines and no hard tissues in their bodies, but they grow at an extremely slow rate, of less than 1 centimeter per year, and can reach over 6 meters in size. Scientists theorize that this long lifespan might be partially due to their extremely slow metabolisms, which they developed to be able to withstand extremely cold waters. These sharks do not reach sexual maturity until they are over 100 years old, so it is vital that the species is protected in their youth so they can continue to maintain their population.     

#19 A Mother Humpback Whale And Her Calf, In A Position Known As “Echelon”

Image credits: freudian_nipps

#20 A Whale Shark Swimming In Bioluminescent Algae Makes It Look Like It Is Drifting Through Space. Video By Mike Nulty

Image credits: Peachy-Persimmons

#21 A Pair Of Eagle Rays Gliding Through The Dark Depths

Image credits: NomadDiver

We all know that dolphins are very vocal and communicate with one another with distinct whistles and clicks, but did you know that dolphins also have dialects and accents just like humans? Researchers from the University of Sassari in Italy studied 188 hours of sounds of various dolphins living among six different communities in the Mediterranean Sea, and found that the length of whistles and variations in pitch differed depending on the location each dolphin was from. The researchers were able to identify 168 distinct sounds that were influenced by each dolphin’s home environment and how many dolphins lived in that area. I wonder if American dolphins like to attempt the accents of British dolphins too…  

#22 The Eye Of A Gray Whale

Image credits: FatimaMahmoud12

#23 He’s Right Behind Me, Isn’t He?

Image credits: dykmoby

#24 Saw Fish From Below

Image credits: tronx69

If you have ever had a baby, that 9 month gestational period probably felt grueling towards the end. But can you imagine being pregnant for 3.5 years at a time? Well, frilled sharks don’t have to imagine it. The mothers of this species can carry their babies for an impressive 40 month period due to their slow metabolic process. “Like most sharks, the frilled shark is ovoviviparous, meaning embryos of this species have no placental connection with their mother. Instead, they emerge from their eggs, staying inside their mother and surviving on yolk until they’re born alive,” Flip Science explains. 3.5 years is a long time, but each mother can have a litter of 2-15 pups during that time. So maybe it’s worth it.

#25 Below A Crocodile

Image credits: RyanSmith

#26 A Diver Taking A Photo Of An Anaconda Underwater

Image credits: Peachy-Persimmons

#27 The Ogre Fish Has Only Been Spotted A Few Times In Decades Of Ocean Research

Image credits: arafaoumma

Comprehending how vast the ocean is feels similar to comprehending space. We are so tiny, but it is amazing to think about how complex life is on our planet. We hope you’re enjoying this list of fascinating sea creatures and that you’re learning something new. Keep upvoting the posts that blow your mind, and then let us know in the comments if you have any wild sea stories to share. Then if you’d like to read another piece about how vast the oceans are, check out this article next. 

#28 The Lizard Fish. Found 8000 Ft Below

Image credits: acid-hologram

#29 Stingray Migration

Image credits: Not_A_Nazgul

#30 Best High Five Ever

Image credits: jtyutjhedr

#31 This Whale My Wife Saw While Supervising A Trydiver. First Dive And You See A Whale. Wtf

Image credits: muhpidu

#32 Rare Footage Of The Giant Squid, Filmed A Few Miles From The Appomattox Deepwater Oil Rig

Image credits: freudian_nipps

#33 This Is What A Blob Fish Actually Looks Like Underwater In Their Natural Habitat

Image credits: fibreusel

#34 The Mantis Shrimp, Thought To Have The Most Complex Visual System Ever Discovered In The Animal Kingdom. Humans Have 3 Types Of Photoreceptor Cells In Their Eyes, While Mantis Shrimp Have Between 12 And 16. They Can See Wavelengths Of Light And Color That Humans Cannot

Image credits: freudian_nipps

#35 We Are Here To Appreciate The Awesome Majesty And Incredibly Cool Aspects Of Nature

Image credits: sohilanoh

#36 Sharks Kill Less Than 6 To 8 People, While Humans Kill About 100 Million Sharks Every Year

Image credits: sohilanoh

#37 For Your Viewing Pleasure: The Viper Dogfish

Image credits: jatadharius

#38 A Killer Whale Jumps 15ft High To Catch Its Prey Which Is A Dolphin

Image credits: t3rm1n470rty

#39 The Antarctic Amphipod Is One Of The Most Alien Creatures To Inhabit The Depths Below

Image credits: Peachy-Persimmons

#40 A Photo Of A Magnapinna Squid Captured By A Deep Sea Drilling Company. They Live So Deep In The Ocean That Very Little Is Know About This Creature

Image credits: MyloWilliams

#41 Pov You’re A Fish In The 1700’s

Image credits: master-jono

#42 A Russian Fisherman Caught A Deep Sea Fish Which Straight Up Resembles A Nightmare

Image credits: Peachy-Persimmons

#43 Two Tiger Sharks!

Image credits: jaykirsch

#44 The Chirodectes (An Incredibly Rare Genus Of Box Jellyfish) Seen Just Twice, This Is The Only Known Footage To Exist. 1st Post More Details

Image credits: TheGuvnor247

#45 When The Kite Falls Out Of The Sky While Kitesurfing And You See This…

Image credits: Antranik

#46 The Frilled Shark. I’m Not Thrilled At All

Image credits: reddit.com

#47 A Vortex Of Fire Under The Surface Of The Water In The Gulf Of Mexico

Image credits: Amiraasabaat

#48 The Portuguese Man O War

Image credits: 404nocreativusername

#49 A Cuttlefish Has Three Hearts, Blue-Green Blood, And Horizontal Vision Which Allows Them To See Behind Themselves

Image credits: acid-hologram

#50 I’ll Be Waiting For You Below

Image credits: elloMinnowPee

#51 Footage From The Mariana Trench. 10,792 Meters (36,000 Feet) Below The Ocean Surface

Image credits: freudian_nipps

#52 Giant Squid Makes An Appearance In Tokyo Bay

Image credits: RyanSmith

#53 Rising Up From The Murky Water Next To My Kayak

Image credits: SeeThroughCanoe

#54 This Red Jellyfish Looks Like A Spaceship

Image credits: acid-hologram

#55 A Giant Squid Eye. It Has The Largest Known Eye In The Entire Animal Kingdom

Image credits: Peachy-Persimmons

#56 A Shark’s Jaw Is Essentially A Conveyor Belt Of Teeth Continuously Rolling Out, Making The Shark Always Ready For Killing

Image credits: gruffness12

#57 The Giant Phantom Jelly

Image credits: QuaintMushrooms

#58 One Of The Few Albino Whales Left On Earth

Image credits: ashley-stewart

#59 Deep Sea Octopus Broods Her Eggs For Over 4 Years – Longer Than Any Animal. Happy Mother’s Day Everyone!

Image credits: Peachy-Persimmons

#60 Octopus With A Disorder That Gave It 96 Arms

Image credits: SynapseAgain

#61 Nope

Image credits: aknasb13

#62 Not Sure If This Qualifies, But This Picture Is The Cause Of The Worst Nightmare I’ve Ever Had

Image credits: OnTheOctopusRide

#63 Hammerhead Sharks Nailing This Group Photo

Image credits: rocklou

#64 A Type Of Hogfish, Fresh Catch

Image credits: jaykirsch

#65 Mother, Calf, And Escort Sleeping Peacefully

Image credits: acid-hologram

#66 King Of The Amazon. The Arapaima

Image credits: mypoopscaresflysaway

#67 Pink Fresh-Water Dolphin In The Amazon

Image credits: jaykirsch

#68 A Whale In Peace

Image credits: Peachy-Persimmons

#69 Deep Blue, One Of The Largest Great White Sharks, Roams The Open Ocean

Image credits: Peachy-Persimmons

#70 Taken From A Fishing Boat In Antartica

Image credits: guitamnandakumar

#71 Huge Loggerhead

Image credits: iancurtis

#72 An Anglerfish Specimen Recovered From The Depths Is The Stuff Of Nightmares

Image credits: Peachy-Persimmons

#73 Crystal Formations Under Water

Image credits: reddit.com

#74 This Absolute Monstrosity Of A Sailfish Belongs Here 100%

Image credits: Torhanmi

#75 The Owlfish Living At Depths Of Over 6,000 Meters (19,685 Feet)

Image credits: Cyber_Being_

#76 Diving Next To An Iceberg

Image credits: RyanSmith

#77 About 345 Million Years Old Almost Intact Crinoid Fossil

Image credits: Appropriate_Stick748

#78 Zebra Shark And Whale Shark

Image credits: Peachy-Persimmons

#79 Nothing Goes To Waste

Image credits: vdub319

#80 Large Wolf Eels Are Curious And Are Rarely Aggressive

Image credits: Cyber_Being_

#81 Japanese Spider Crab, Human For Scale

Image credits: jaykirsch

#82 Equally Awesome And Terrifying

Image credits: gracelouiseh

#83 Only You And Him

Image credits: juanmaschw

#84 How A Blobfish (A Deep Sea Fish) Looks With And Without The Extreme Water Pressure

Image credits: TheBluntReport

#85 The Alien Tripod Fish And Its Strange Fins That Suspend It

Image credits: Peachy-Persimmons

#86 This Is The Thaumatichthys Axeli. It’s A Bizarre Angler Fish With A Light Source Inside Of Its Mouth And It Looks Like A Vacuum Cleaner

Image credits: Peachy-Persimmons

#87 Lumpsucker, Found In The Freezing Waters Of Arctic, North Atlantic, And North Pacific. It Swims At Depths Of 1,700 M (5,600ft)

Image credits: jatadharius

#88 The Vampire Squid

Image credits: Samyewel

#89 Does This Go Here? Idk It Just Instills Fear Deep Within My Soul

Image credits: maggotchild_

#90 A Diver And A Southern Right Whale

Image credits: RyanSmith

#91 Hungry Carp Look Straight Out Of Lovecraft

Image credits: JCarnacki

#92 An Alligator Bellow

Image credits: freudian_nipps

#93 No One Likes A Show Off, But Still Worth Sharing, I Thought!

Image credits: iwasasin

#94 A Giant Squid We Pulled Up In Our Nets

Image credits: DeepSeaNomad

#95 9 Eyes, 7 Pairs Of Legs, Blue Blood & 10 Claws

Image credits: SeeThroughCanoe

#96 Look Look

Image credits: ShimaaElsayed

#97 The Fangtooth Moray Has A Mouthful Of Semi-Transparent Teeth That Looks Like Glass

Image credits: acid-hologram

#98 Divers Encounter The Sunfish, Which Can Weigh Over 4k Pounds

Image credits: ThatOnePogger

#99 The Ancient One: The Coelacanth

Image credits: Peachy-Persimmons

#100 The Extinct Shark Helicorpion Who Had A Circular Saw Of Teeth As Its Lower Jaw

Image credits: anonking64

#101 Have A Terrifying Picture Of A Squid With Seemingly Human Teeth. However, The Teeth Are Just Nodes Of Flesh

Image credits: Peachy-Persimmons

#102 Alligator Snapping Turtle From R/Thalassophobia

Image credits: TheOfficialMarley

#103 Huge Underwater Statue In The Bahamas

Image credits: srsdrgdf

#104 A Moray Eel With A Disfigured Face Resides In An Aquarium. That Or This Creature Is A Lovecraftian God

Image credits: Peachy-Persimmons

#105 Rare Sighting Of The Megamouth Shark, Reaching Up To 18 Feet In Length And 2,700 Pounds With A Mouth Measuring 4.3 Feet In Width. This Shark Can Have Up To 50 Rows Of Teeth In Its Upper-Jaw And 75 Rows Of Teeth In Its Lower-Jaw

Image credits: freudian_nipps

#106 A Dolphin In An Aquarium Window

Image credits: MellotronSymphony

#107 A Big Nope!

Image credits: bogeyz

#108 Fish Swimming In The Wake Of A Pelagic Jellyfish

Image credits: RyanSmith

#109 Constant Vigilance

Image credits: giraffewoman

#110 A Colossal Squid Beak. The Colossal Squid Is The Heaviest Invertebrate Alive, And It Uses The Beak To Defend Itself And Gouge Out Flesh

Image credits: Peachy-Persimmons

#111 A Portuguese Man O’ War Found Washed Up At Galvestonis East Beach

Image credits: FatimaMahmoud12

#112 The Pacific Blackdragon

Image credits: In-Jail-Out-Soon

#113 When Something From The Depths Below Makes It’s Way Onto Land

Image credits: 5_Frog_Margin

#114 Mobula Ray Migration In The Sea Of Cortez

Image credits: acid-hologram

#115 Japanese Spider Crab. Their Legs Can Be Up To 12 Feet Long

Image credits: LadyTerror0813

#116 The Sailfish, Commonly Regarded As The Fastest Fish In The World. It Exceeds 110 Kilometres Per Hour. Another Candidate Is The Black Marlin

Image credits: Peachy-Persimmons

#117 Thresher Sharks Like To Breach Often

Image credits: Peachy-Persimmons

#118 Can Anyone Help Identify This?

Image credits: Zealousideal-Day9239

#119 Scarry

Image credits: reddit

#120 I Made A Friend Who Wants To Be A Great White Shark Diver, And Says Things Like He Is Already Committed To Sacrificing His Left Arm As A Last Resort. Most Of The Pictures He Posts On His Feed Are Worthy Of This Sub

Image credits: reddit.com

#121 Spotted This Huge Jellyfish At A Promenade In Venice

Image credits: Compris-Nauta

#122 A Thresher Shark Is In Solitude. Its Tail Is Almost Its Body Length

Image credits: Peachy-Persimmons

#123 A River Dolphin’s Face. Its Eyes Have Degraded To The Point Of Blindness, But It Utilizes Echolocation To Find Its Prey

Image credits: Peachy-Persimmons

#124 The Indo-Pacific Sailfish, Considered By Many Scientists To Be The Fastest Fish In The Ocean

Image credits: freudian_nipps

#125 A Pod Of Spinner Dolphins

Image credits: acid-hologram

#126 A Sturgeon That Lives Behind My House. Around 6 Feet Long

Image credits: Acutifolia

#127 Alligator Gars Are Massive Apex Predators Of Freshwater Areas. Their Fossil Traces Back To The Cretaceous Era, True Primal Beasts. Just Imagine Feeling The Hide Scaly Hide Of That Thing

Image credits: Peachy-Persimmons

#128 Abandoned Underwater Restaurant

Image credits: reddit.com

Source: boredpanda.com