From the ancient descriptions of crustaceans and mollusks by Aristotle to the cutting-edge genetic testing and crowdsourcing methods used to discover new species today, the ocean remains a realm of mystery and wonder. “It’s the unknown,” 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 on the ocean and you might see a dolphin or a whale, but you don’t see what goes on beneath,” he adds. “We know only a fraction of the number of species down there.” The following sea creatures showcase just how captivating and surprising the ocean’s depths can be.
Vampire Squid
Despite its ominous name, the vampire squid is neither a vampire nor a true squid. This deep-sea cephalopod, known scientifically as Vampyroteuthis infernalis, has a gelatinous body with webbed arms that give it a cloak-like appearance. “I suspect that the red eyes and the cape led him to say, ‘that looks like a vampire,’” says Bruce Robison, a senior scientist at the Monterey Bay Aquarium Research Institute, referring to the creature’s discoverer, German teuthologist Carl Chun. Chun’s 1903 description of the vampire squid as “vampire squid from hell” was more about its dramatic appearance than its behavior.
The vampire squid feeds on marine snow—floating debris such as algae, dead plankton, and fecal matter—rather than blood. It has a unique defense mechanism: when threatened, it can release a cloud of luminous mucus from pores at the ends of its arms, creating a glowing shield to evade predators. This adaptation helps it survive in the dark depths of the ocean where it dwells.
Hoodwinker Sunfish
The hoodwinker sunfish, or Mola tecta, is a recently discovered species that was only identified in 2017 by Ph.D. student Marianne Nygaard and her team in New Zealand. The name “tecta” is derived from the Latin word “tectus,” meaning concealed or hidden, reflecting the fish’s elusive nature. This massive sunfish can weigh up to 2,000 pounds and is known to inhabit cold waters in the southern hemisphere, including off the coasts of New Zealand, Australia, Chile, Peru, and South Africa. Recent sightings have even extended its known range to the coast of California and as far north as Alaska.
Sunfish are known for their varying appearances within the same species, and they can change morphology as they grow, making them difficult to identify. The hoodwinker sunfish’s latest sighting was in June 2024, when a sunfish measuring 7 feet, 3 inches washed up on a beach in Oregon. Initially mistaken for the more common ocean sunfish, Nygaard confirmed it was indeed Mola tecta, demonstrating how this species continues to elude complete understanding.
Pram Bug
The pram bug, or Phronima, is a deep-sea amphipod that inhabits the twilight zone of oceans worldwide, typically between 200 and 1,000 meters below the surface. Despite its somewhat benign name, pram bugs are cunning parasites. They prey on salps, gelatinous creatures that resemble jellyfish. The female pram bug uses her crab-like claws to hollow out the interior of a salp, then lays her eggs inside the empty shell. Once the eggs hatch, the pram bug larvae live within the salp’s protective shell. The mother then propels the salp forward like a pram, carrying her young as they develop.
This behavior is not just fascinating but also highlights the intricate survival strategies of deep-sea creatures. Pram bugs are clear and small, making them difficult to spot, but their complex interactions with their environment and their method of using salps as mobile nurseries showcase the bizarre and intricate life forms that exist in the ocean’s depths.
These remarkable sea creatures demonstrate just how little we know about the depths of our oceans. Each discovery adds a piece to the puzzle of marine biodiversity and emphasizes the importance of continued exploration and research. The ocean remains one of the last frontiers of our planet, full of astonishing life forms that continue to captivate and surprise scientists and enthusiasts alike.
