10 Astonishing Deep Sea Creatures That Seem Too Strange to Exist

Hidden in the shadowy depths of the ocean floor lies a mysterious world of deep sea creatures that few humans have ever seen.

This ecosystem, one of the largest on Earth, plunges to depths of 35,876 feet (10,935 meters). It thrives on marine snow, the continuous fall of organic matter from shallower waters, which sustains countless deep-sea life forms. Despite its vastness, much of it remains uncharted.

Below are some of the fascinating creatures inhabiting the deep ocean floors of the Pacific, Antarctic, Atlantic, and Indian Oceans that we have managed to learn about.

1. Pelican Eel

The pelican eel (Eurypharynx pelecanoides), a member of the gulper eel family, possesses an enormous, pelican-like mouth designed to engulf its prey. Similar to others in the Eurypharyngidae family, its mouth makes up roughly a quarter of its slender body, capable of expanding to consume prey whole.

Pelican eels inhabit the mesopelagic zone, often referred to as the twilight zone, dwelling at depths exceeding 9,000 feet (2,700 meters). They share this eerie environment with other intimidating deep-sea dwellers such as the vampire squid.

2. Fangtooth Fish

The common fangtooth (Anoplogaster cornuta), a deep-sea fish seldom encountered, is described by the Monterey Bay Aquarium Research Institute (MBARI) as "nearly as mysterious as it is mesmerizing."

The fangtooth fish derives its name from the pair of elongated, razor-sharp teeth extending from its upper jaw. As noted by the Smithsonian Institution, these teeth are the largest among marine creatures relative to its body size, which can reach up to 7 inches (18 centimeters). Additionally, it boasts two prominent fangs protruding from its lower jaw.

This deep-sea predator feeds on small crustaceans, cephalopods, and other fish by rapidly opening its mouth and creating a suction effect, akin to a deep-sea vacuum. "They appear to consume anything that fits into their mouths," explained Tracey Sutton, a professor at the Guy Harvey Oceanographic Center at Nova Southeastern University in Florida, in an interview with Newsweek.

Fangtooth fish are predominantly found in the mesopelagic (twilight) and bathypelagic (midnight) zones, residing at depths ranging from 1,650 to 7,000 feet (500 to 2,100 meters). However, they have been observed as deep as 16,000 feet (nearly 5,000 meters).

3. Japanese Spider Crab

The Japanese spider crab (Macrocheira kaempferi), boasting a leg span of up to 12 feet (3.8 meters), holds the title of the world's largest crab. It inhabits the mesopelagic (twilight) zone of the Pacific Ocean, dwelling at depths between 660 and 1,800 feet (200 to 550 meters).

Equipped with 10 legs, the Japanese spider crab uses eight for walking while the remaining two feature claws for grasping. This deep-sea dweller roams the ocean floor, scavenging for decaying plants and animals.

4. Sea Cucumber

While many deep-sea creatures remain elusive due to their proximity to the ocean floor, sea cucumbers (class Holothuroidea) thrive in both shallow and deep waters. They feed by using their tube feet to collect algae and organic debris from the seabed.

Belonging to the echinoderm family, which includes sea stars and urchins, sea cucumbers come in over 1,200 species. The smallest, Psammothuria ganapati, measures just 0.16 inches (4 millimeters), while the largest, Synapta maculata or snake sea cucumber, can reach lengths of up to 10 feet (3 meters), as documented by the Natural History Museum.

5. Frilled Shark

Despite sharing the same class (Chondrichthyes) as the great white shark, the 7-foot (2-meter) frilled shark (Chlamydoselachus anguineus) resembles an eel more than a shark. "Its head looked like something straight out of a horror film," said fisherman David Guillot, who unexpectedly caught one in 2015, during an interview with 3AW radio.

This ancient deep-sea predator, dating back 80 million years, inhabits a range from the pelagic to the benthic zones, spanning depths from 164 feet (50 meters) to approximately 5,000 feet (1,500 meters) below the surface.

The Shark Research Institute notes that the frilled shark may swim with its mouth agape, using its "strikingly white teeth" to lure prey before engulfing them whole.

6. Giant Isopod

The giant isopod (Bathynomus), a deep-sea crustacean closely related to roly-polys and pill bugs, varies in size from 3 to 20 inches (8 to 51 centimeters). Despite this range, it far surpasses most marine isopods, which can be as tiny as 0.01 inches (0.3 millimeters).

Exhibiting deep-sea gigantism, a trait shared with creatures like the giant squid and Japanese spider crab, the giant isopod thrives at depths between 550 and 7,020 feet (170 to 2,140 meters).

"To our knowledge, they primarily act as scavengers," explained Ruth Carmichael, a senior marine scientist at the Dauphin Island Sea Lab and professor of marine and environmental sciences at the University of South Alabama, in an interview with Mytour. "They are crucial for recycling nutrients and elements" by consuming decaying fish, crustaceans, and sea sponges on the ocean floor.

7. Giant Sea Spider

Resembling a daddy longlegs, the giant sea spider (Colossendeis) features slender, elongated legs attached to a compact body. However, unlike its terrestrial counterpart, this creature thrives in the ocean's depths rather than in the corners of your home.

While some sea spiders are minuscule, with legs as short as 0.03 inches (1 millimeter), the giant sea spider, inhabiting depths of 7,200 to 13,100 feet (2,200 to 4,000 meters), can grow up to 20 inches (51 centimeters) in length.

8. Sea Pig

Sea pigs (Scotoplanes), with their peculiar appearance, are among the most unusual deep-sea creatures. Despite their name, they are not related to pigs but are a type of sea cucumber, named for their pinkish, translucent bodies and short tube-like legs. Like pigs, they are opportunistic feeders, consuming almost anything they encounter.

As reported by MBARI, sea pigs grow up to 6.4 inches (17 centimeters) and inhabit depths ranging from 3,300 to 19,500 feet (1,000 to 6,000 meters). They thrive on the abyssal plains, feeding on decaying organic matter found on the ocean floor.

9. Deep-sea Anglerfish

The term anglerfish (occasionally written as "angler fish") encompasses approximately 200 species of deep-sea fish. These species inhabit depths of up to 16,400 feet (5,000 meters) and vary in size from 0.25 inches (6.2 millimeters) to 4 feet (1.2 meters) in length.

Anglerfish are categorized into four groups: batfish, goosefish, frogfish, and deep-sea angler.

"New species are still being discovered," said Ted Pietsch, a professor at the School of Aquatic and Fishery Sciences at the University of Washington and author of "Oceanic Anglerfishes: Extraordinary Diversity in the Deep Sea," in an interview with Mytour. "They inhabit such extreme depths that we lack a clear understanding of their maximum size. When we deploy nets to collect them, the deeper we go, the larger the specimens we retrieve."

Anglerfish use a glowing lure at the end of a dorsal appendage to attract bioluminescent bacteria, which in turn draws in prey. In this species, only the females hunt. Females are significantly larger than males — up to 60 times their size — and supply nutrients to their male partners.

10. Sea Angel

Unlike the foot of a typical land snail, the sea angel (clade Gymnosomata) possesses two wing-like structures that enable it to glide gracefully through the water.

The Monterey Bay Aquarium describes the sea angel as "a shell-less variety of swimming snail." Their translucent bodies are fully visible, which is why they are named Gymnosomata, meaning "naked body."

Sea angels feed on other swimming snails, such as sea butterflies, using a tentacle-like appendage to extract the soft tissue from their shells. Despite their predatory nature, sea angels are tiny, measuring only 0.4 to 0.78 inches (1 to 2 centimeters) in length. They inhabit depths ranging from the surface down to 5,921 feet (1,805 meters).