For centuries, the ocean has captivated human imagination. From Aristotle documenting sea life on ancient scrolls to modern-day researchers using cutting-edge technology to uncover new species, our fascination with the mysteries of the deep continues to grow.
“It’s the mystery,” says Erich Hoyt, author of Creatures of the Deep: In Search of the Sea’s Monsters and the World They Live In. “You look out over the ocean and see a whale or dolphin, but beneath the surface, there’s an entire world we barely understand.” Despite our advances, we’ve only just begun to scratch the surface of the countless species that call the ocean home.
Seven Unbelievable Sea Creatures
Here are seven incredible sea creatures that stand out for their unique traits and the intrigue they inspire.
1. Vampire Squid
Despite its ominous name, the vampire squid is neither a vampire nor a squid. Bruce Robison, a senior scientist at the Monterey Bay Aquarium Research Institute, has been studying this deep-sea dweller for years. “The name came from its appearance—red eyes and a dark ‘cape’—but it’s a gentle scavenger,” he explains.
First identified by German teuthologist Carl Chun in 1903, the Vampyroteuthis infernalis (literally “vampire squid from hell”) feeds on marine snow—tiny bits of detritus like dead plankton and algae that drift down from the ocean surface. But don’t underestimate this small cephalopod; it has a clever defense mechanism. When threatened, the vampire squid can release a cloud of biol
2. Hoodwinker Sunfish
The hoodwinker sunfish is a relatively new discovery in the marine world. Classified as Mola tecta, this elusive species was first identified in 2017 by Ph.D. student Marianne Nyegaard and her team in New Zealand. The name “tecta” comes from the Latin word for hidden or concealed, fitting for a creature that managed to remain undiscovered for so long.
“It’s fascinating that this fish evaded recognition despite significant interest in sunfish species,” says Nyegaard. The hoodwinker sunfish inhabits cold waters in the Southern Hemisphere, including the coasts of New Zealand, Australia, Chile, Peru, and South Africa. Although these fish can weigh up to 2,000 pounds, their appearance varies significantly within the species, making identification challenging. One notable sighting occurred in June 2023, when a 7-foot, 3-inch sunfish washed up on an Oregon beach, initially mistaken for the more common ocean sunfish before being correctly identified as Mola tecta.
3. Pram Bug
The pram bug, scientifically known as Phronima, is a tiny but cunning predator that resides in the ocean’s twilight zone, typically between 200 and 1,000 meters below the surface. Despite its innocuous-sounding name, which comes from the British term “pram” (a stroller), the pram bug is anything but gentle.
These amphipods, also known as barrel shrimp, prey on gelatinous creatures called salps, which resemble jellyfish. The pram bug’s strategy is gruesome: the female uses her sharp claws to hollow out a salp, turning it into a living nursery for her eggs. Once inside, she propels the salp forward, using it as a mobile home for her offspring. When the young hatch, they devour the salp from within, continuing the cycle. “It’s a stark contrast to the idea of nurturing motherhood,” notes Hoyt.
4. Flower Hat Jellyfish
The flower hat jellyfish, Olindias formosa, is as beautiful as it is dangerous. Found off the coasts of Japan, Brazil, and Argentina, this jellyfish is known for its vibrant, multicolored tentacles, which it uses to lure small fish.
Although the flower hat jellyfish typically measures only about six inches in diameter, its sting can cause significant pain and a rash, though it is not lethal to humans. The jellyfish alternates between the sea floor and coastal waters and occasionally forms large groups known as blooms. These blooms often occur when warmer waters provide an abundance of food, leading to a population surge. The flower hat jellyfish has inspired both awe and caution, as its stunning appearance belies its potentially harmful sting.
5. Gulper Eel
The gulper eel, also known as the pelican eel (Eurypharynx pelecanoides), is a creature straight out of a sci-fi movie. Found in the midwater zone of the eastern Pacific Ocean, this eel is most notable for its massive, expandable mouth, which can balloon out to capture prey much larger than itself.
This adaptation is crucial for survival in the deep sea, where food is scarce. Although its teeth are small, the gulper eel’s oversized mouth allows it to scoop up a wide variety of prey. In 2018, a juvenile gulper eel was filmed by explorers aboard the Nautilus E/V at the Papahānaumokuākea Marine National Monument in Hawaii. The video, which has garnered millions of views, showcases the eel’s unique feeding method and eerie, Muppet-like appearance.
6. Colossal Squid
The colossal squid (Mesonychoteuthis hamiltoni) is the largest invertebrate ever recorded, dwarfing even the famous giant squid. First identified in 1925 by zoologist Guy Robson, this deep-sea giant was discovered after two of its tentacles were found in the stomach of a sperm whale that washed ashore in the Falkland Islands.
In 2007, fishermen in the Ross Sea, south of Antarctica, accidentally caught a colossal squid weighing over 1,000 pounds, one of the largest specimens ever recorded. Despite its massive size, the colossal squid had never been observed alive in its natural habitat until recently. In 2023, deep-sea explorer Matthew Mulrennan captured video footage that may show a baby colossal squid in the Southern Ocean, offering a rare glimpse into the life of this elusive creature. Analysis is ongoing to confirm the discovery.
7. Archerfish
Archerfish, native to Southeast Asia and northern Australia, are renowned for their incredible precision when hunting both in and out of water. These tropical fish are not only adept at catching crustaceans in the ocean but are also skilled at shooting down insects perched on branches above the water.
Using a specialized mouth structure, archerfish can expel water with pinpoint accuracy to knock prey into the water, where it becomes an easy meal. “Their ability to shoot down prey is remarkable,” says Eileen Caro, a biologist at The Florida Aquarium. “They can even leap up to a foot out of the water to snatch insects.” Archerfish typically range in size from 4 to 11 inches, but their hunting prowess makes them stand out in the animal kingdom.
