Biology of Subnautica: Below Zero | Part II

Welcome back to Curious Archive. This video
is the finale of my two-part series on the biology of the video game Subnautica: Below
Zero. Deeper within this alien ocean, astonishing ecosystems, shocking mysteries, and chilling
terrors still await discovery. And much like how the strangest life in Earth’s oceans
dwells in the abyss, the depths of Sector Zero open a whole new world of surprises.
I’ve also found it an even more frightening place to do field work. And with a mysterious
signal calling out from the deep at the end of the last video, who knows what final secrets
Planet 4546B is hiding. So, join me on the last section of our documentary-style voyage,
as we conclude this expedition into the unknown… The mysterious transmission is emanating from
the murky waters of a region known as the Deep Twisty Bridges. Diving into these alien
depths, the only light comes from the bioluminescent coral bridges that spiral throughout this
cavernous abyss. The dimness of the deep has transformed all life that swims in the gloom.
Like pale ghosts, the skeletal Spinefish haunt the depths.

A subspecies of the hoopfish,
the Spinefish have become nearly translucent, and possess rib-like markings that give them
a deathly appearance. The phenomenon of certain deep-sea fish becoming transparent is present
in Earth’s oceans as well — notably in the Barreleye Fish — an animal that possess
a head made of translucent tissue to allow it to look upwards and spot its preferred
prey. Truthfully, the Barreleye Fish is an animal that would seem right at home in the
oceans of Planet 4546B. But the Spinefish isn’t a carnivore, so despite its haunting
appearance, it’s no real danger. But there are genuine dangers here. A huge predator
swims, torpedo-like, among the bridges. With unexpected speed, it rushes in and attempts
to swallow me whole, a fate I’m barely able to avoid by prying its jaws open. The predator
continues to give chase, but I escape by swimming into a crevasse it can’t reach. That terror
of the abyss was a Squidshark — a highly aggressive fauna species that is the apex
predator of this region.

Analysis suggests its terrifying burst of speed comes from two
vents on either side of its body, which provide jet propulsion. Through this adaptation, the
Squidshark, like its name suggests, combines the most formidable aspects of deep-sea squids
and macropredator shark species. The result is a deadly amalgamation I’ll have to keep
a wide distance from if I ever want to find the source of the transmission. Staying close
to the ocean floor, a curious, waving plant catches my eye. Swimming in for a closer look,
the lifeform lashes out with a long tendril and pulls me towards a mouth-like opening.
After a few frantic punches, the creature releases its tentacle and I swim out of range.
That was a Spikey Trap — which isn’t actually a plant at all, but a highly unusual form
of animal.

This carnivorous lifeform blends into the terrain, camouflaging itself among
vegetation, and catching fish — and unwary explorers — with its adhesive tendrils when
they swim too close. And despite its lack of mobility, this strategy seems to be highly
effective. In the Deep Twisty Bridges, one must always stay alert. Elsewhere on the sea
floor, I discover a strange, glowing device near the signal’s source. This ruined fragment
matches the strange structures present in the tropics, which belonged to a group of
alien architects.

I’d assumed all the architects had perished… but with the signal beckoning
me onwards, I wonder if I was mistaken… At last, I reach a mysterious undersea facility.
As I navigate through the halls, a mysterious voice urges me to hurry. Entering a central
chamber, I find the signal and the voice have been coming from this cube-shaped computer.
The voice turns out to be that of an architect who, thousands of years before, had stored
his consciousness within the computer. Speaking through the cube, the architect explains he
was a scientist like me, and is now likely the last of his kind. Wanting to help a fellow
researcher, I offer to transfer the lonely consciousness to my field computer and take
him with me on my expedition. The Architect accepts, and warns me to… brace for transfer?
A little too late, I realize something might have been lost in translation… Awakening
with a mild headache, I can hear the Architect’s voice quite clearly… and learn this is because
he downloaded himself directly into my brain. It was an honest mistake, as Architects don’t
recognize a boundary between technology and the body.

While this is an intriguing revelation
about Architect biology, it means I now have an unanticipated mental roommate… Returning
to the shallows, we formulate a plan. We’ll use our combined knowledge to continue to
chart the biology of life in Sector Zero, but along the way we’ll gather the material
needed to fabricate a body that my new friend can transfer into. He tells me his designation
is A L dash A N… so I’ll call him Alan. Picking up where Alan’s research left off,
we venture to the sprawling expanse of the West Arctic. Here, great icebergs float above
a seemingly bottomless region of the sea — creating a profound sense of scale. And among these
icebergs swim undiscovered oddities. Gliding through the blue, is an animal that is difficult
to unravel. With two sets of wing-like fins, it’s not clear what sort of lifeform we’re
observing at a glance. But this lifeform is, in fact, an Arctic Ray, the first of many
Ray species in Sector Zero. While its body plan has clearly diverged from Earth rays,
by having four wing-structures instead of two, the Arctic Ray is a highly agile lifeform…
And it has to be, if it wants to avoid the top predator of the West Arctic.

This is a
Pinnacarid, an intelligent and social predator that spends half its time on ice floats above
the water. Pinnacarids have converged on an ecological niche similar in many respects
to Earth seals, and are remarkably friendly towards humans, even showing acute curiosity
when lured in with a tasty piece of fish. Alan’s analysis suggests their fourteen
flippers make them acrobatic hunters underwater. This unusually high number of flippers resembles
the anatomy of the Anomalocarids, a group from Earth’s Cambrian Period who similarly
possessed multiple fins for locomotion. Descending deeper into the West Arctic waters, what appear
to be a legion of pulsating eyes stare back at us. This is, in fact, a colony of Eye Jellies,
gelatinous lifeforms that harbor an enormous hemispheric eye on the tops of their bodies.
Despite their alarming appearance, these creatures live remarkably passive lives, drifting slowly
on the currents in vast colonies, paying little mind to other species.

Alan warns me that
they are capable of releasing a small electric shock if we swim too close, however, so we’ll
give the group a wide berth. Upon one of the West Arctic icebergs, we notice an entrance
to a small cave. Venturing inside, the reflected ice caught in the afternoon sun resembles
the brilliance of the night sky. And within this ethereal cave, a strange egg appears
stranded on the cave wall. It’s not a species Alan recognizes, and it seems about ready
to hatch. We bring the egg to the warmth of the shallows, after some time, this creature

The unusual hatchling turns out to be a Trivalve, and much like the Cuddlefish
of the tropics, it’s a remarkably friendly and intelligent creature that is quite a fan
of treats. A scan suggests the body of this naturally inquisitive creature is made of
a flexible exoskeleton, and somewhat resembles the shell of an earth Nautilus in its shape.
It’s tempting to relax in the shallows with the Trivalve for longer, but Alan reminds
me we still have other areas to chart. The next leg of the journey will be perilous indeed.
Luckily, I have a new classification of submersible to aid in the voyage. This is a Sea Truck,
an underwater vehicle that will allow us to go lower into the crushing depths of Sector
Zero than ever before. At the helm of the Sea Truck, we venture into the vast biome
of the Thermal zone. The edge of this region, an area known as the Thermal Spires, is marked
by a forest of hydrothermal vents. These chimney-shaped structures are formed from dissolved minerals
pushed up from the planet’s crust, and are home to all kinds of remarkable life. Gliding
between the vents is a brightly-colored Feather Fish.

Defined by their unusual, crescent-shaped
fin structure, Feather Fish are one of the more graceful herbivores in Sector Zero. A
highly successful species, in some regions they gather in schools numbering in the thousands.
We are admiring one such school, when an intimating creature paddles by. This vicious-looking,
armored predator is a Cryptosuchus, and is covered in sharp spines. Snapping wildly,
it closes in… then retreats just as quickly. As it turns out, the contrarian Cryptosuchus
is one species where its bark is truly worse than its bite. While it appears fearsome,
a scan suggests its bladed shell is adapted to aid in heat absorption among thermal vents.
And so, this false tyrant paddles away, to try and scare off something a bit smaller…
Far deeper into the Thermal Zone, the dark blue of a biome known as the Tree Spires beckons.
These waters are lit by the bioluminescent flora that grow on the sides of tree-like
hydrothermal vents.

In this distinctive region, the equally distinctive Discus Fish ungulates
along. Its flat, semi-transparent body is highly unusual, and it seems to contain strange
green organs. A study of the Discus Fish reveals this green color comes from symbiotic algae-like
organisms living within specialized body cavities that provide the Discus Fish with food. Strange
as this might sound, Emerald Sea Slugs of Earth also photosynthesize using algae that
grow within their bodies. Since there isn’t much sunlight here in the depths for plant
growth, it’s likely the Discus Fish spends part of its lifecycle in a brighter region
of Sector Zero. Elsewhere in the Thermal Zone, we can spot a teardrop-shaped Arrow Ray.

ray species has an elongated body and a rather triangular head, which it can tilt to perform
unpredictable maneuvers. At the ends of the Arrow Ray’s fins grow sharp, talon-like
tips that deter attackers who manage to catch up — meaning the Arrow Ray certainly isn’t
defenseless. A huge lifeform passes in front of our submarine. Without warning, it shrieks
and latches onto the windshield with its front mandibles, pulling us towards its gullet.
Gunning the engine, I’m barely able to twist out of the deadly grip.

That leviathan class
organisms was a Chelicerate, a brute that grows over 130 feet, or 40 meters in length.
Its body is covered in a thick, segmented exoskeleton that grows in overlapping plates,
which may offer protection from the atmospheric pressure. Since the Chelicerate are so aggressive
and potentially deadly, they’re a challenging species to study up close. Fascinating as
they are, we both hope we don’t encounter any more of them. At the very bottom of the
sea floor, an indescribably massive lifeform is waiting. This is a Ventgarden, a stationary
leviathan that anchors itself above thermal hydrovents and consumes 100% of the nutrients
the vents release. At over 360 feet, or 110 meters, the Ventgarden is, by far, the largest
Leviathan of Sector Zero. The only things in Earth’s Oceans that resemble Ventgardens
are certain types of siphonophores — soft bodied entities, which, like the Ventgardens,
are also technically colonies of smaller organisms working in tandem.

But what’s most incredible
about the Ventgarden is the internal ecosystem of plants it supports within its hollow, bell-shaped
center. And remarkably, a scan indicates it would be safe to enter this environment ourselves.
Exiting the submarine, we tentatively swim up towards the light, and at last emerge within
the microcosm of the Ventgarden. This mini-ecosystem supports aquatic flora on branching platforms
that in turn help absorb some of the heavy metals emitted by the vents below. Exploring
the hidden biosphere of a Ventgarden is a downright magical experience… But the unknown
still beckons. Pushing further into the abyss than ever before, we’ve reached the edge
of the habitable region for most Fauna. Surrounded by total darkness, Alan is starting to get
worried that we’ve strayed too far. And he seems to be right. A huge Chelicerate emerges
from the blackness, almost twice the size as the one from the Tree Spires.

This pale
mutation is called a Void Chelicerate, and it’s not alone. We’ve stumbled into a
pack. Time to head back as fast as we possibly can. I don’t think either of us plan on
revisiting this area any time soon. Returning to the safety of the research base, I have,
with Alan’s help, given our station a bit of an upgrade. As it turns out, having an
alien scientist downloaded into your brain can be quite useful.

And while Alan still
doesn’t understand the purpose of basic things like music, or why I start every morning
with coffee, together, we’ve successfully mapped much of Sector Zero. Yet a deep scan
tells us that there’s a strange signature coming from a large ice cave we’ve yet to
chart… The cave is far to the inland of Sector Zero, across the frigid tundra. At
last, we enter the cavern and discover an enormous, frozen creature encased in a cave
wall. This leviathan class organism has been entombed here for thousands of years, as Alan
remembers encountering their kind when he was a researcher here long ago. Since this
species is, hopefully, now extinct, the only way to study it is to drill into the ice.
Taking a DNA sample from the creature’s foot, I’m able to determine the lifeform
was quadrupedal, and spent at least a portion of its time on land — something unusual
for planet 4546B.

Perhaps this Frozen Leviathan suggests an era in the distant past where
land was more plentiful, and great titans like this one roamed across it. In any case,
I’m certainly glad this particular specimen is now long dead. I think. At long last, we
now have all the necessary materials needed to fabricate Alan’s new body. The only problem
is that the Architect Facility that can create such a compatible vessel is located in a region
known as the Crystal Caves. These caverns are the deepest biome of them all, and the
last frontier of planet 4546B.

And since the refractive crystals mean any scans of the
region come back fragmented, there’s no telling what else is down there… Navigating
the purple chasm, this environment possesses a strange beauty. And equally strange lifeforms
navigate their depths. The Triops is a tiny lifeform that spends much of its time hiding
from predators in the surrounding terrain. The Triops stand out biologically, however,
thanks to their distinctive, three-eyed ocular system. In nature, a lifeform evolving three
distinct eyes isn’t particularly common… but it’s not altogether unheard of. Artemia
is a genus of aquatic crustaceans that possess two eyes mounted on flexible stalks and a
third, stationary eye situated in the center of their head.

So, the diminutive Triops is
in good company. Further into the planet’s crust, we’ve arrived at the Fabricator Caves:
a secondary layer of the Crystal Caves, where a high concentration of the element Beryllium
led to the formation of striking red crystals. To brave this extreme geochemical environment,
I’ve donned the Prawn Suit: a deep-sea mechanical walker that kept me safe on the last stages
of my journey in the tropics.

Stomping along the ocean floor, I spot a small crustacean
nearby. Given its diminutive stature, I’m not particularly worried, until it launches
itself at my Prawn Suit. This is a Rock Puncher, a pint-sized predator which is a heavy-hitter
nonetheless. Its hardened chitin (kite-in) claws can thrust forward at close to the speed
of sound to break rock and bone alike. In many respects, the Rock Puncher is similar
to the precocious Mantis Shrimp.

These unsuspecting creatures possess spring-loaded biological
hammer-clubs that can strike prey faster than the speed of a bullet, giving the Mantis Shrimp
the ability to truly punch above its weight class. And the Rock Puncher is not different.
Time to deescalate the situation… by moving elsewhere. We’re now very close to the Fabrication
facility, when a thunderous roar shakes the cavern. A huge Leviathan grips my Prawn Suit
and pulls me towards a glowing gullet. After smacking it with my prawn-suit’s arms, the
nightmarish serpent temporarily drops me. Backing into a narrow gap, it seems the leviathan
cannot follow. We’re safe… for now. That was a Shadow Leviathan, which at almost 200
feet, or 60 meters, is the single most dangerous predator of Sector Zero.

It’s black, elongated
body gives this monster the appearance of a giant eel. Analysis suggests its bioluminescent
digestive tract glows due to light seeking phytoplankton that draw in unwary fish, and
also secrets a highly acidic compound. I’m lucky I was able to escape such a terrifying
lifeform unscathed. Or have we? Looking up, I notice my Prawn Suit is leaking from its
fight with the Shadow Leviathan. Our only hope now is to reach the Fabrication facility
before the Shadow finds me again. But with the familiar green glow of Architect technology
up ahead, at last, we’ve reached the ultimate destination. Heading inside, I find a facility
quite like the one I first discovered Alan inside. Putting in the materials we’ve gathered,
the facility begins the process of fabrication. Activating the final sequence, Alan and I
watch as the vessel is constructed. This new body is composed of the DNA of 27 different
species, and various inorganic materials as well — so it should be quite the upgrade.
At last, Alan’s body is complete. After so much effort, it’s almost surreal to reach
this point. I think about telling my friend he looks a bit like a glowing purple centaur…
but decide that would probably just confuse him.

With Alan now out of my mind and in his
new vessel, he doesn’t need my assistance to continue his research. We both return to
the surface, and Alan informs me he’ll be going back to his home planet via Warp Gate,
to see if there are any other Architects still living. It is a somewhat bittersweet feeling
as I realize this is goodbye.

Working with another researcher — in particular an alien
one — has been a special privilege. Alone on Planet 4546B once more, I consider all
I’ve seen on this wondrous planet. From nerve-wracking dangers to unexpected allies,
it’s been a remarkable journey. But now, at last, the time has come for me to depart
as well. For who knows what else might be waiting for us among the stars…? If you
enjoyed discovering the creatures of Subnautica, please follow and support creature designer
Alex Ries using the links below.

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