How would you feel if you were asked to explore the Mariana Trench, the deepest oceanic trench on Earth, and encounter the weirdest and most mysterious animals it holds beyond its darkness?
I can’t blame you if this thought scares you, especially with its blackest abyss of 36,037 feet, the Challenger Deep.
However, is it really possible for life forms to exist with water pressure that is 1,000 times greater than at sea level? The answer is yes! Let us shed light on some of these amazing creatures of the deep in this article!
11 Strange and Scary Animals in the Mariana Trench
1. Dumbo Octopus
| Animal Name: | Dumbo Octopus |
| Scientific Name: | Grimpoteuthis |
| Special Features: | Two large fins that give the appearance of having giant ears; bioluminescence; ability to camouflage |
| Habitat: | Coast of Oregon, Papua, New Guinea, and the Gulf of Mexico, as well as the Philippines and Australia |
| Depth Range: | 9,800–13,000 feet (2,987–3,962 meters) |
| Diet: | Isopods, crustaceans, pelagic copepods, worms, and small fish |
| Behavior: | Loves to play with objects around them |
| Conservation Status: | Least Concern |
The dumbo octopus, or Grimpotheuthis, stands out because of its unique, ear-like fins that resemble the Disney character Dumbo.
First spotted in 1883, these mysterious creatures live in the ocean’s depths, up to 13,000 feet below the surface. Despite their discovery over a century ago, much about them remains unknown due to their elusive nature.
Dumbo octopuses roam the deep sea floor, hunting for snacks like isopods and crustaceans. They’re skilled at catching their food, swallowing it whole without hesitation.
These octopuses are solitary, facing few threats thanks to their remote habitat. They can also change color to blend in and avoid predators.
Remarkably, they don’t have a specific breeding season, which helps them overcome the rarity of encounters with potential mates. Once the eggs are laid, the young are on their own, equipped to survive from birth.
2. Black Seadevil Anglerfish
| Animal Name: | Black Seadevil Anglerfish |
| Scientific Name: | Melanocetidae |
| Special Features: | Sharp fangs; bioluminescent lure; misshapen body |
| Habitat: | Atlantic and Antarctic Oceans |
| Depth Range: | 656–6,562 feet (200–2,000 meters) |
| Diet: | Shrimp, snails, crustaceans, small fish, and even some larger fish |
| Behavior: | Opportunistic feeders; bottom-dwellers |
| Conservation Status: | Least Concern; one species tagged as “outside safe biological limits” by ICES |
Easily recognized by its distinct glow, the black seadevil anglerfish is a scary sight — thanks to their large heads, cold stares, and mouths equipped with translucent, sharp teeth.
Their most famous feature is the illicium, a light-up lure that dangles from their heads to attract prey in the pitch-black waters.
These fish, especially females, can devour prey much larger than themselves. Their ability to expand their jaws and stomachs allows them to tackle sizable meals, a handy skill since food in the deep sea is often scarce.
Sadly, black seadevil anglerfish are facing threats from overfishing and climate change. Hence, living at depths that are mostly beyond human reach helps preserve the species.
Fun Fact: Reproduction among anglerfish is quite unusual. The smaller males attach to their mates to survive, relying on them for nutrients.
This bizarre mating strategy ensures that when a female is ready to lay eggs, she has a male already connected to provide fertilization.
3. Deep-sea Dragonfish
| Animal Name: | Deep-sea Dragonfish |
| Scientific Name: | Stomiidae |
| Special Features: | Transparent, fang-like teeth; hinged skull; bioluminescent photophores |
| Habitat: | Amazon River Basin; mesopelagic and bathypelagic zones, where there is very little or no daylight. |
| Depth Range: | 656–16,400 feet (200–5,000 meters) |
| Diet: | Small marine organisms, worms, insects, brine shrimp, squid, insect larvae, algae |
| Behavior: | Opportunistic hunter; undergoes vertical migration during breeding season |
| Conservation Status: | Least Concern |
Otherwise known as the viperfish, the deep-sea dragonfish can be easily recognized by its elongated body and massive needle-like teeth.
These creatures thrive in the darkest parts of the ocean, from the mesopelagic to the bathypelagic zones, reaching depths where it’s pitch black.
Despite the challenging conditions of their habitat, they have evolved unique adaptations that ensure their survival in the deep. Examples of these are their hinged skull and shock-absorbing joints.
With a length of up to 30 cm, their jaw extends beyond their mouth to accommodate their oversized teeth.
Further, research findings indicate that the transparent teeth of deep-sea dragonfish are made of nanocrystals that prove to be stronger compared to the teeth of piranhas and great white sharks.
Deep-sea dragonfish also lack a swim bladder, relying instead on gelatinous tissues for buoyancy.
As apex predators, they consume shrimp, small fish, and other marine life. Their luminescent sides and bellies act as lures that attract prey. Once the prey is close enough, they strike with swift, lethal accuracy.
4. Frilled Shark
| Animal Name: | Frilled Shark |
| Scientific Name: | Chlamydoselachus anguineus |
| Special Features: | Large, oil-filled liver for buoyancy |
| Habitat: | Outer continental shelf and upper continental slope of the Atlantic and Pacific Oceans |
| Depth Range: | Below 4,000 feet (1,219 meters) |
| Diet: | Fish, sea slug, squid, and other sharks |
| Behavior: | Ambush predators; solitary creatures; deep-sea dwellers |
| Conservation Status: | Least Concern |
The frilled shark was first documented in the 19th century by Ludwig H.P. Döderlein. With an appearance that dates back to ancient times, it’s no wonder they’re called a “living fossil.”
Their body, stretching up to 6 feet long, is adorned with unique frilly gills, earning them their name. These sharks are deep-sea dwellers, preferring the shadowy depths 4,000 feet below the surface.
In fact, their habitat is so remote that encounters with humans are rare, and the sharks usually don’t survive the trip to the surface. This makes studying their behaviors and life cycles a significant challenge.
Armed with over 300 trident-shaped teeth across 25 rows, frilled sharks are formidable predators. Their large mouths and specialized teeth ensure prey rarely escapes once caught.
Scientists believe their hunting method resembles that of land-based snakes, striking swiftly at their prey in the dark ocean depths.
5. Goblin Shark
| Animal Name: | Goblin Shark |
| Scientific Name: | Mitsukurina owstoni |
| Special Features: | Long, snout-like nose |
| Habitat: | Canyons and continental slopes of Pacific, Atlantic, and Indian Oceans; around Southern Brazil, France, Madeira, and Senegal |
| Depth Range: | 330–4,270 feet (100–1,300 meters) |
| Diet: | Squid, fish, cephalopods, and crustaceans |
| Behavior: | Bottom-dwellers; ambush predators; solitary creatures |
| Conservation Status: | Least Concern |
The second shark entry in this list is the goblin shark, also known as the “elfin shark,” Like the frilled shark, they have an ancient lineage — dating back 125 million years!
Their unique appearance features a protruding jaw and pink-toned skin. They are even compared to dinosaurs due to their ancient roots and distinct features.
Goblin sharks inhabit the ocean’s dark depths, typically around 330 to 4,270 feet below the surface. They are found globally, from the Pacific to the Atlantic, preferring continental slopes and underwater canyons.
Their diet mainly consists of deep-sea fish, crustaceans, and cephalopods, and they utilize their electro-sensitive snouts to detect prey. Goblin sharks are also ambush predators, striking swiftly with their protruding jaws.
These creatures are thought to be viviparous. Their juveniles spend time in shallower depths than adults.
Despite the fearsome looks of these sharks, they live secluded lives and rarely interact with humans or the surface world.
6. Sea Cucumber
| Animal Name: | Sea Cucumber |
| Scientific Name: | Holothuroidea |
| Special Features: | Tube feet; retractable tentacles; leathery skin |
| Habitat: | Worldwide, but mainly in the Pacific Ocean |
| Depth Range: | 6,562–31,168 feet (2,000–9,500 meters) |
| Diet: | Algae, plankton, and detritus |
| Behavior: | Social; bottom-dwellers; active during the day |
| Conservation Status: | Least Concern |
The sea cucumber belongs to the class Holothuroidea, which is of the same echinoderm family as starfish and sea urchins. Predominantly found in the Pacific Ocean, they live at depths from 6,500 to 31,100 feet.
These marine animals vary in size, ranging from 0.12 inches to a massive 10 feet, but most are between 4 and 12 inches long.
Their bodies, which can be spherical to worm-like, lack limbs and are supported by tiny, calcified structures within the skin.
They are also unique due to their bioluminescent capabilities, which allow them to camouflage by adjusting the glow of their bodies to match the ocean’s light from above.
These creatures thrive on the ocean floor and play a big role in recycling nutrients and breaking down biological matter. Each processes around 100 pounds of sediment annually and turns it into finer byproducts.
Sea cucumbers also feed on tiny particles like algae and microscopic organisms by using their tentacle feet around their mouths.
7. Snailfish
| Animal Name: | Snailfish |
| Scientific Name: | Liparidae |
| Special Features: | Scaleless; loose, gelatinous skin; small teeth; prominent sensory head pores; tadpole shape |
| Habitat: | Widely distributed from the Arctic to the Antarctic Oceans |
| Depth Range: | Surface to 26,200 feet (surface –8,000 meters) |
| Diet: | Copepods and amphipods for juveniles; fish, crustaceans, gammarid, krill, and Natantian decapods for adults |
| Behavior: | Deep-sea dweller |
| Conservation Status: | No available information |
The snailfish, known scientifically as Liparidae, is found in the salty depths of the world’s oceans. There are over 410 species of these carnivorous creatures.
Their appearance is quite distinct; they resemble tadpoles or snails without shells, earning them the nickname “sea snail.”
Snailfish have evolved unique traits to adapt to the extreme pressures of the deep sea. Their bones have softened over millions of years, allowing them to withstand crushing depths.
Instead of swim bladders for buoyancy, they produce a gelatinous substance. Some species even have antifreeze proteins in their DNA to survive the icy waters of their deep-sea homes.
Snailfish diet varies with their size and development stage. While juveniles feast on a variety of tiny sea animals like copepods and amphipods, adults have a more diverse menu, including krill, crustaceans, and small fish.
8. Vampire Squid
| Animal Name: | Vampire Squid |
| Scientific Name: | Vampyroteuthis infernalis |
| Special Features: | Gelatinous body; a pair of small er-like fins; bioluminescent organs |
| Habitat: | Worldwide in tropical to temperate latitudes |
| Depth Range: | 1,600–9,800 feet (500–3,000 meters) |
| Diet: | Zooplankton and miscellaneous detritus |
| Behavior: | Prefers oxygen minimum zones (OMZs) |
| Conservation Status: | Least Concern |
The vampire squid is a deep-sea cephalopod that thrives in oxygen minimum zones (OMZs). They are able to survive this environment since they have the lowest metabolic rate among all deep-sea cephalopods.
These creatures are also identified for their two long, retractable filaments that distinguish them from other octopuses and squids.
Aside from these traits, vampire squids showcase other evolutionary features for deep-sea survival. Their gelatinous body, cloaked in a web of skin that connects eight spiny arms, aids their camouflage in the deep.
Further, with eyes large enough to gather scarce light, these creatures master the art of stealth by using light-producing organs to blend with their surroundings or confuse predators.
Despite their scary name, vampire squids feed on ocean detritus, not the blood of other creatures.
Their reproductive cycle also makes them distinct from other cephalopods. They are able to undergo multiple reproductive cycles, unlike their cousins that have just a single high-energy cycle in their lifetime.
9. Comb Jelly
| Animal Name: | Comb Jelly; Comb Jellyfish |
| Scientific Name: | Ctenophora |
| Special Features: | Two main layers of cells that sandwich a middle jelly-like layer; notable for their cilia, used for swimming; retractable tentacles; gelatinous body; bioluminescence |
| Habitat: | Oceans, brackish bays, marshes, and estuaries worldwide |
| Depth Range: | 23,700 feet (7,224 meters) |
| Diet: | Other ctenophores, zooplankton, small crustaceans, fish larvae, and mollusk larvae. |
| Behavior: | Solitary |
| Conservation Status: | No available information |
A comb jelly, or ctenophore, can glide through the ocean using rows of cilia that resemble combs. These jellies can grow from a tiny 0.04 inches to an amazing 4.9 feet and may take a variety of forms, from spheres to ribbons.
In marine habitats worldwide, comb jellies exhibit dazzling displays. Transparent species near the surface scatter light into rainbows, while deeper dwellers may flash bioluminescent signals when disturbed.
As carnivores, they employ tactics from sticky lures to web-like tentacles to capture their zooplankton prey.
Reproduction among comb jellies is fascinating, with most species being hermaphrodites capable of both self and cross-fertilization.
Their lifecycle can potentially extend up to three years. This happens even without parental care, as they transition directly from fertilized eggs to adult form.
10. Grenadier Fish
| Animal Name: | Grenadier Fish Rattail |
| Scientific Name: | Macrourinae |
| Special Features: | Large head; rat-like tail; bioluminescence in some species |
| Habitat: | Benthic region from the Arctic to the Antarctic Oceans |
| Depth Range: | 660–22,970 feet (200 to 7,000 meters) |
| Diet: | Smaller fish, cephalopods, lanternfish, and pelagic crustaceans such as shrimp, amphipods, and cumaceans. |
| Behavior: | Deep-sea dwellers; apex predators in benthic area; scavengers |
| Conservation Status: | No available information |
The grenadier fish, also known as rattail, is a family of deep-sea fish known for their distinctive large heads, big mouths, and slender bodies that taper to thin tails. This gives them their common name.
Grenadiers also possess a highly developed lateral line system, enhanced by chemoreceptors on their heads and lips. These sensors aid in their deep-sea navigation.
These fish can be found at depths of about 200 to 7,000 meters, from the Arctic to the Antarctic, making them one of the most common deep-sea fish.
Further, they play crucial roles as both apex predators and scavengers in their ecosystems. They feed on a variety of smaller fish and crustaceans.
When it comes to reproduction, some species can produce over 100,000 tiny eggs that rise to shallower waters to develop.
However, despite the abundance and large size of grenadiers, efforts to commercialize them have failed due to their unpalatable taste.
11. Basket Star
| Animal Name: | Basket Star, Snake Star |
| Scientific Name: | Gorgonocephalus eucnemis |
| Special Features: | Repeating branched arms |
| Habitat: | Bering Sea to Japan and Baja California, also Arctic Ocean and North Atlantic Ocean |
| Depth Range: | 30–6,100 feet (100–1,800 meters) |
| Diet: | Plankton and drifting organic material |
| Behavior: | Seamount dwellers |
| Conservation Status: | No available information |
The basket star belongs to the suborder Euryalina and is a unique brittle star with branching or curling arms.
Some, known as “basket stars,” have arms that branch out extensively, while others, called “snake stars,” feature long, curling limbs.
These creatures are often found in deep-sea environments or cold waters, though some are visible on tropical reefs at night.
Basket stars can live up to 35 years and grow large, with some reaching 70 cm in arm length.
They use their complex arms, equipped with microscopic hooks and sticky mucus, to capture zooplankton and other tiny food particles from the ocean currents.
Food is then transported to their mouths located on the underside of their central discs.
These echinoderms thrive on seamounts, where underwater currents bring a concentration of nutrients.
Their presence indicates a healthy, biodiverse habitat. However, their existence is often jeopardized by human activities like fishing and seabed mining.
Other Known Animals Discovered in the Mariana Trench
With the vast expanse and unimaginable depth of the Mariana Trench, one thing is for sure — there are more creatures that have developed adaptations to survive in this environment and even more to be discovered.
Here is a list of fish species that have called the Mariana Trench their home:
- Abyssal Snailfish
- Alaska Snailfish
- Appendage-less Snailfish
- Aquavit Hatchetfish
- Arbiter Snailfish
- Atlantic Footballfish
- Atlantic Silver Hatchetfish
- Babbie Snailfish
- Big-eye Snailfish
- Binocular Fish
- Black Dragonfish
- Black Mirrorbelly
- Black Snailfish
- Black-tail Snailfish
- Blind Snailfish
- Blunt-tooth Snailfish
- Broad-mouth Snailfish
- Brownsnout Spookfish
- Cape Snaggletooth
- Cherry Snailfish
- Comb-side Hatchetfish
- Combed Snailfish
- Comic Snailfish
- Common Fangtooth
- Dana Viperfish
- Derjugin’s Snailfish
- Diaphanous Hatchetfish
- Doubtful Snailfish
- Drop-shaped Snailfish
- Dusty Snailfish
- European Anglerfish
- False Oblique Hatchetfish
- Fanfin Angler Fish
- Finely-speckled Snailfish
- Firm-body Snailfish
- Frilled Shark
- Froggy Snailfish
- Fulvous Snailfish
- Gelatinous Snailfish
- Giant Hatchetfish
- Giant Rattail
- Glasshead Barreleye
- Goldeneye Snailfish
- Grey Mirrorbelly
- Hairy Angler
- Half-naked Hatchetfish
- Highlight Hatchetfish
- Horned Lantern Fish
- Humpback Anglerfish
- Javelin Spookfish
- Kara Snailfish
- Keel-belly Snailfish
- Kido’s Snailfish
- Kiwi Hatchetfish
- Knipowitsch’s Snailfish
- Long-feather Snailfish
- Marginate Snailfish
- Mariana Snailfish
- Merret’s Snailfish
- Mirrorbelly
- Mischievous Snailfish
- Moskalev’s Snailfish
- Murray’s Abyssal Anglerfish
- Nutting’s Hatchetfish
- Obese Dragonfish
- Pacific Footballfish
- Pacific Hatchetfish
- Pacific Viperfish
- Paxton’s Hatchetfish
- Peach Snailfish
- Peach-skin Snailfish
- Pellucid Snailfish
- Prickly Anglerfish
- Rose Snailfish
- Rough Snailfish
- Round Snailfish
- Salmon Snailfish
- Sea Tadpole
- Silvery Hatchetfish
- Shorthorn Fangtooth
- Sloane’s Viperfish
- Slope Hatchetfish
- Small-disk Snailfish
- Small-eye Snailfish
- Small-fin Snailfish
- Small-spine Snailfish
- Smalltooth Dragonfish
- Snaggletooth
- Spectral Snailfish
- Spiny Snailfish
- Spookfish
- Stippled Snailfish
- Tapir Snailfish
- Telescope Snailfish
- Threadfin Dragonfish
- Tidepool Snailfish
- Toge Snailfish
- Triplewart Seadevil
- Tropical Hatchetfish
- Whiskered Snailfish
- Winged Spookfish
Meanwhile, here are some of the invertebrates that share the Mariana Trench with the fishes:
- Black Teatfish
- Brown Sea Cucumber
- Deep Water Redfish
- Emperor Dumbo Octopus
- Giant California Sea Cucumber
- Hermann’s Sea Cucumber
- Hirondellea gigas
- Lyre Sponge
- Panning’s Blackfish
- Pineapple Sea Cucumber
- Sandfish
- Sea Walnut
- Surf Redfish
- Venus Girdle
- White Teatfish
- Xenophyophores
Frequently Asked Questions
Is Megalodon Present in Mariana Trench?
No, it is difficult to imagine that these prehistoric sharks that lived 2.5 to 3.5 million years ago can live and survive in the harsh environment of the Mariana Trench. Here are some reasons why:
- They are warm creatures, and they are not fit for the cold temperatures of the deep sea.
- They feed on large animals, which are scarce in the Mariana Trench.
- There is no evidence of their bite marks on larger animals like whales, and there are no fallen teeth on the ocean floor.
- Their existence would mean that breeding must be sustained, and with their size, it should be easy to notice them.
- Even the main competitors of these sharks, the great white sharks, are a dwindling population. The megalodons couldn’t outsurvive these sharks in the modern environment.
What Shark Lives in the Mariana Trench?
There are two known species of sharks with adaptations that allow them to live in the tough environment of the Mariana Trench — the frilled shark and the goblin shark.
Unlike other groups of sharks that can be found near the water’s surface, both species of sharks prefer environments below 1,000 meters, so encounters with both species are rare.
How Deep Is the Mariana Trench?
The Mariana Trench is about 35,876 feet (10,935 meters) deep. Just to compare, you can easily fit Mount Everest’s 29,031 feet (8,849 meters) inside the trench.
Its deepest point is a valley named Challenger Deep, which is located towards its southern end.
We hope that your fear of these deep-sea animals has turned to fascination as you got to know more about them! Which Mariana Trench animal interests you the most? Let us know in the comments below!
