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. 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 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

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

Image credits: esbohigatns

#3 The Cutest Shark Attack Ever

Image credits: SYLOH

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 Amazon River Dolphins

Image credits: Neon_Jam

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

Image credits: Peachy-Persimmons

#6 Below A Crocodile

Image credits: RyanSmith

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 Sleeping Sperm Whales

Image credits: KevlarYarmulke

#8 It's Not All Bad Down There

Image credits: reddit.com

#9 Great Googly Moogly

Image credits: KingNeptune767

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 Meet "Inspector Clouseau", The World’s Only Pink Manta Ray

Image credits: Peachy-Persimmons

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

Image credits: Peachy-Persimmons

#12 Giant Sturgeon In The Fraser River, Canada

Image credits: hecticaesthetic

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.

#13 The Eye Of A Gray Whale

Image credits: FatimaMahmoud12

#14 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

#15 A Diver Taking A Photo Of An Anaconda Underwater

Image credits: Peachy-Persimmons

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

Image credits: freudian_nipps

#17 The Lizard Fish. Found 8000 Ft Below

Image credits: acid-hologram

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

Image credits: muhpidu

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

Image credits: freudian_nipps

#20 Giant Squid Makes An Appearance In Tokyo Bay

Image credits: RyanSmith

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

Image credits: Amiraasabaat

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 Rising Up From The Murky Water Next To My Kayak

Image credits: SeeThroughCanoe

#23 Huge Loggerhead

Image credits: iancurtis

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

Image credits: sohilanoh

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 For Your Viewing Pleasure: The Viper Dogfish

Image credits: jatadharius

#26 Okey, I Have To Admit This Is Almost Cute... Almost

Image credits: Nidhoggking

#27 Meet This 90 Year Old Turtle!⁠

Image credits: Ghada0_Ahmed

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.