Buzz
Forget about Mars. Dive deep enough, and you'll find yourself on an entirely different world. Far beneath the surface, you’ll encounter beings older than dinosaurs and ancient forests from forgotten times.
While the view is spectacular, divers also face perilous situations, such as navigating toxic currents and dealing with whales in a less-than-friendly mood. And then there are the brave individuals who risk everything to rescue creatures ranging from the world’s largest fish to some of its most venomous.
10. A Cute Yet Carnivorous Blob
When diver Emeric Benhalassa recently explored a diving spot near Bali, he captured footage of a charming blob. The creature appeared otherworldly, yet scientists have been aware of them for some time. Even its name is endearing—the nudibranch.
These small, hand-sized creatures are actually sea slugs. With hues ranging from green to yellow-brown, they possess long bodies with appendages resembling legs and heads that look like balloons. The particular species in question, Melibe viridis, is a common type of nudibranch. What made the footage remarkable was its rare capture of the creature’s feeding behavior.
The nudibranch has a fascinating method to make up for its poor eyesight. It extends its head like a net, sweeping it across the seafloor. Along the edge of its head are rows of sensors. When these detect a small crab or snail, the gelatinous head quickly snaps shut, trapping its prey.
9. Jellyfish as Big as Humans
Biologist Lizzie Daly went swimming off the coast of Cornwall, United Kingdom. Fortunately for jellyfish enthusiasts, Dan Abbott joined her. The underwater cinematographer captured the rare encounter on film.
While diving near the southwestern tip of England, the duo spotted a massive jellyfish rise from the depths. It was a barrel jellyfish (Rhizostoma pulmo), a rare species also known as the dustbin-lid jellyfish.
Unfortunately, its 'head' really does resemble a dustbin lid. The large dome is followed by eight thick arms and tentacles capable of delivering a sting. As the largest jellyfish species in the United Kingdom, these human-sized creatures are typically seen when they wash ashore. For divers to observe a live barrel jellyfish drifting gracefully through the ocean is an extraordinary occurrence.
8. A Perplexed Remora
Two divers were exploring a coral reef off the coast of Egypt when one of them noticed they had gained an unexpected companion. It was a remora (also known as a suckerfish). These creatures possess a suction-cup-like organ on their heads, which they use to latch onto larger hosts. Remoras then feast on leftovers from whatever the host kills in a messy manner.
This is why they prefer to attach themselves to sharks. The particular remora was attempting to latch onto one of the divers. The encounter was captured on film and released in 2017. The footage showed the fish swimming around the diver, nibbling at his diving suit, and persistently following him as he continued exploring the reef.
Measuring from 0.3 to 0.9 meters (1–3 ft) in length, remoras seem to have a habit of mistaking divers for sharks. Enric Sala, a marine biologist, has witnessed this behavior on multiple occasions. While diving near the Southern Line Islands in 2009, he too was pursued by a remora.
7. Underwater Forest
Divers have come across ancient tree stumps beneath the water before, but nothing compared to the discovery made by a British diver who explored the waters off the coast of Norfolk.
In 2015, Dawn Watson was swept off course by rough waters and ended up in a location where the seafloor was covered with large oak trees. It was revealed to be a forest that had been submerged for 10,000 years.
The discovery wasn’t just remarkable because of its age. This prehistoric forest spanned thousands of acres that once formed the land bridge connecting continental Europe to Great Britain. Known as Doggerland, this area was home to Mesolithic hunter-gatherers, as suggested by artifacts recovered by fishermen.
Around 10,000 years ago, the forest thrived, offering abundant hunting grounds for both humans and animals. Today, the oak trees are home to a different kind of visitor. Several species of marine life now use the forest as a reef.
6. A Porcupinefish Rescue
Porcupinefish are often mistaken for pufferfish, and it's easy to see why. Like pufferfish, they inflate to enormous sizes to avoid being eaten by predators. Their bodies are covered in long, sharp spikes, and certain organs contain the deadly toxin tetrodotoxin, which is 1,200 times more poisonous than cyanide. This toxin also coats their skin.
For obvious reasons, few would dare to handle a live porcupinefish with bare hands. However, YouTuber Kye Bolen posted a video where a diver did just that. The diver found a porcupinefish with a large hook lodged in its mouth.
The diver carefully held onto the fish, making sure not to startle it. The fish remained remarkably calm and did not inflate, which would have been dangerous as its spikes would have posed a threat to the diver.
The diver gently worked to wiggle the hook free, but near the end, a few tough tugs caused the porcupinefish to puff up. Undaunted, the diver held the fish by its head to avoid the spikes and successfully removed the hook.
5. A Glowing Nest
In 2017, a scuba diver made an astonishing discovery off the coast of Australia. He stumbled upon what appeared to be a mysterious creature—tube-shaped, translucent, and enormous. To add to the wonder, it was glowing.
While some speculated that the glowing tube could be a strange, unknown beast, biologists had a different explanation. It wasn’t a creature but the nest of a squid, filled with strings of eggs that had a soft pink, pearl-like sheen.
Pinpointing the squid that laid these eggs is no easy task. Though the answer isn’t certain, researchers believe the tube likely came from the elusive diamond squid (Thysanoteuthis rhombus).
These kite-shaped creatures are known to remain with their mates for about a year, their full lifespan. The glow of the tube is emitted by the eggs themselves. While the cause of the shimmer remains a mystery, researchers discovered a potential clue when they studied diamond squid larvae. In a previous study, baby squid hatched from diamond eggs showed pigment cells that could produce both red and yellow colors.
4. Entangled Whale Shark
In 2018, scuba divers alerted Hawaii’s Department of Land and Natural Resources to a distressing situation. A whale shark, the largest fish species in the world and a vulnerable creature, had become entangled in a rope. Unfortunately, the divers were unable to assist.
Later that same year, a Hawaiian family of free divers was exploring the waters near Lanai. Although they had many years of experience, they had never encountered a whale shark before. Their excitement grew when they discovered a young female shark swimming deeper beneath them.
However, it soon became apparent that the shark was in serious distress. A heavy rope had caused significant damage, leaving deep cuts on her pectoral fin and leaving scars along her back.
To rescue the shark, the father carried out a series of two-minute dives, reaching a depth of 18 meters (60 ft). The shark's composure was astonishing. Typically, whale sharks flee when touched, but this one allowed the man to cut the rope for over 30 minutes until she was set free.
3. River Wrapped In Poison
Cenote Angelita, located in Mexico's Yucatan Peninsula, appears to be a typical freshwater pool from the surface. However, when divers descend around 30 meters (100 ft), they are met with an unbelievable sight—an underwater river. A thick mist surrounds it, enveloping the river with a blanket that’s at least 3 meters (10 ft) deep.
Some divers who venture into the mist experience panic. This cloud is composed of pure hydrogen sulfide, making for a disorienting and hazardous swim. The gas is deadly if inhaled, making it an unnerving atmosphere to find yourself lost in.
The river is actually a halocline, which occurs when freshwater and seawater meet but cannot fully mix due to differences in density. This creates the river-like boundary in the cenote.
The merging of these waters formed the halocline river, a brackish stream that lies beneath freshwater yet above saltwater. The river is thick enough to prevent organic matter, like forest debris, from sinking through it. This results in decomposition, which releases hydrogen sulfide that stays within the stream.
2. A Creature Older Than The Dinosaurs
In the depths of the ocean exists a remarkable creature—the bluntnose sixgill, a large shark that has roamed the seas since before most dinosaurs even walked the Earth. This 200-million-year-old species likely survived the Permian-Triassic extinction event, which wiped out 96% of sea life.
Having witnessed the rise and fall of the notorious megalodon shark, the sixgill shark endures to this day. While researchers are eager to study this ancient being, its deep-sea habitat makes accessing it incredibly challenging.
In 2019, scientists embarked on a daring journey to explore the depths in a submersible. Their efforts paid off in the Bahamas. At a depth of 990 meters (3,250 ft), they encountered a massive sixgill shark. This 4.9-meter-long (16 ft) female seemed intrigued by the submersible, batting her large blue eyes at the researchers and gently nudging the vessel.
However, the shark's power intensified when it aggressively attacked the bait outside the submersible, shaking the vessel and alarming everyone inside. She was too close to be tagged. But later that evening, scientists managed to find a male sixgill, who became the first animal to receive a tracker tag launched from a submarine.
1. Whale Roughing Up A Diver
Humpback whales are often portrayed as gentle giants. Marine biologist Nan Hauser, with 28 years of experience diving with these magnificent creatures, couldn't fully argue with that—until an incident in 2018.
While diving off the coast of the Cook Islands with her team, a massive humpback whale approached Hauser. The 22,700-kilogram (50,000 lb) whale became a bit too playful, seemingly determined to place Hauser on its head or tuck her under one of its massive pectoral fins.
For over 10 minutes, the biologist maintained her composure. While the whale's actions were not violent, the size difference between them made the encounter potentially life-threatening. At one point, the whale even lifted her partially out of the water.
Once back on the boat, Hauser realized the situation was more complicated than simply encountering an aggressive whale. On the other side of the humpback, a 4.6-meter-long (15 ft) tiger shark was lurking. Meanwhile, a second humpback was splashing the water near the predator.
Humpback whales have been documented rescuing seals and the calves of other whale species from orcas. If this behavior was similar, it would mark the first known instance of these gentle giants protecting a human from danger.
