The vast oceans of the popular video game Subnautica teem with alien creatures — some
friendly — and some deadly.
While the game focuses on survival, the lifeforms of Subnautica are amazing even when they’re
trying to eat you: possessing fascinating biology, bizarre behavioral patterns, and
hidden mysteries.
So, for this entry into the archive, we’ll embark on a documentary-style expedition,
touring ecosystems from the shallows to the abyssal trenches; swimming in the shadows
of giants, and evading predators of the deep.
This series will reveal the biology behind these puzzling lifeforms, and investigate
how they differ from life in our own oceans.
And although it’s been a while since this Archivist has done any fieldwork, I’ll be
diving into the perilous seas of planet 4546B myself to capture footage of these magnificent
lifeforms.
So, let’s take the plunge together, and see what awaits us under the surface…
Beginning in the safety of shallow warm waters, we find that stable conditions have led to
a region crowded with varied life.
Here, you can encounter all manner of undersea organisms.
One of the first lifeforms we can spot are the Peepers… or rather, they spot us, with
their enormous, dinner-plate like eyes.
These easily identifiable creatures have evolved visual sensors capable of discerning colors
not just in clear waters but in a variety of lighting conditions.
This, combined with their surprising speed, means that despite being herbivores, Peepers
aren’t at the bottom of the food chain.
That distinction instead belongs to these creatures, the rather unfortunate looking
Garryfish.
Docile herbivores that are remarkably slow, the Garryfish make easy prey for most anything
else in these shallow waters.
All ecosystems, including the oceans of earth, need something near the bottom of the food
chain, after all.
Other common herbivores on 4546B include the Bladderfish, which swims by contracting and
expanding its translucent bladder, and the unusual Boomerang, a horizontally symmetrical
oddity that possesses a mouth full of sharp teeth to break down coral.
On the subject of coral, the landscape of the Safe Shallows is dominated by one particularly
unusual lifeform.
These gargantuan tubes are large enough to swim through, and despite appearances, are
very much alive.
Aptly called Giant Coral Tubes, they don’t look much like the coral we know on earth.
These tubes have evolved to filter nutrients that flow through their center, and judging
by their size and abundance, it’s a strategy that has been quite successful.
Gliding near the tubes is the elegant Rabbit Ray — the first of many ray species we may
encounter.
The undulating motion that the Rabbit Ray uses to swim through the clear seas is analogous
to the underwater movements of various types of earth rays.
But it’s not the movement of the Rabbit Ray that gives it its curious name.
Instead, the Rabbit Ray’s most defining features are its twin orange appendages that
help it sense vibrations.
These ear-like structures resemble the ears of rabbits, and so the aquatic Rabbit Ray
shares a name with an otherwise dissimilar terrestrial herbivore.
Beneath the shallows twist a network of underwater caves.
While exploring one as I gathered this footage, I heard a strange noise…
And a fish exploded in my face.
That short-lived creature was a Crashfish — an evolutionary oddity that is difficult
to study due to its highly frustrating habit of exploding when anything gets close.
The Crashfish is defending the sulfur plant, that provides the Crashfish its home.
While an animal exploding to defend its territory might seem too outlandish to evolve, there’s
a model of such behavior on our own planet.
Though uncommon, certain species of ants have been observed erupting into goo to block tunnels
when their nest is under threat.
Truly, nature is highly unusual — no matter the planet.
Elsewhere in the caves, the far less bothersome Shuttlebugs drift near the stone walls.
Shuttlebugs are challenging creatures to make sense of: with three legs and three mandibles
that have evolved into fin-like tentacles.
Despite looking slightly unsettling, analysis suggests Shuttlebugs are too small to be a
threat to most organisms, and have instead adapted to feed on the waste products of the
ecosystem around them.
Leaving the caves, you’ll see our first large species is waiting for us: the Gasopods.
These rotund, leathery beasts resemble Earth manatees, yet have a curious defense that
is all their own.
Although not in any way hostile, when threatened, the Gasopods will nonetheless release a deadly
cloud of underwater mist… which I can’t recommend ingesting.
Chemical analysis of the Gasopods tells us the poisonous compound comes from the bulbous
appendage at the end of their tail.
Since Gasopods are social creatures, it’s possible they even use these clouds to communicate
with one another.
But while the Gasopods are the largest creatures in the Safe Shallows, they are barely the
tip of the proverbial iceberg when it comes to planet 4546B.
Venturing into the vast Kelp Forest, we’ll find a radically different environment than
the region we just left.
Here, the light is low thanks to the high volume of creepvine plants — creating a
hidden ecosystem, just like kelp-heavy regions in Earth’s oceans.
Here and there, clusters of Creepvine Seeds cast shadows across the environment like natural
floodlights.
I find myself wondering just what might be hidden among the swaying fronds…
That is a Stalker: the largest predator that makes its home in the dense Creepvines.
These fearsome customers possess a series of dorsal ridges to help them make tight turns.
Their long, thin snout is likely adapted for ensnaring fish, as it greatly resembles the
effective, slender snout of real-life gharials.
Yet at the edge of the Kelp Forest, one Stalker is behaving… rather oddly.
This Stalker is picking up various pieces of metal scrap with its snout, only to drop
them after a short period.
This behavior seems to serve no practical purpose, and indeed the stalkers seem to simply
have a fondness for shiny objects.
Puzzling as this behavior might seem, the barracuda — a predatory earth fish — is
also known to be attracted to shiny objects because it’s evolved to spot the silvery
glint of the fish it prefers to prey on.
And when one considers the common prey of the Stalker, this attraction to shiny materials
makes perfect sense.
In the murky depths of the Kelp Forest, schools of fast-moving hoopfish light up the dark
with their vibrant coloring.
A brief study of hoopfish anatomy reveals they get their name from their antennae, which
extends from the top and bottom of their heads and bends around their tails — forming a
hoop.
Exactly why these stunning fish possess such intense and varied colors, however, is a mystery.
On the subject of mysteries, the last fish of the Kelp Forest we’ll see is quite the
enigma.
Meet the Hoverfish: a peaceful herbivore that appears to ‘hover’ on the pads at the
ends of its six legs.
Using these strange appendages, the Hoverfish glides on the undersea currents in a manner
quite dissimilar to any other fish on the planet.
It’s surprising to learn, therefore, that the hoverfish may actually be a distant relative
of the nondescript bladder-fish, with their ‘legs’ a highly derived form of the bladderfish’s
primitive vacuole tubing.
It’s the kind of creature that could only exist in the Kelp Forest.
Just beyond the waving Creepvines, the landscape gives way to an alien Grassy Plateau.
Here, the sandy terrain is almost completely carpeted with Blood Grass, as the seafloor
is too deep for Creepvines to take hold.
And in the open space, even larger lifeforms are on the prowl…
At the edge of the Grassy Plateau, a strange cloud of sand is gathering.
Be cautious—as we swim closer to the unexpected turbulence, a creature with a huge, fanged
mouth lashes out.
This is a Sand Shark, a predator with a distinctive hunting strategy.
The Sand Shark burrows into the sand, then erupts out when unsuspecting prey swims by:
ending the chase with a snap from its massive jaws.
With segmented body armor and six rows of fearsome teeth, it’s little wonder why these
predators are so effective.
Alien as this behavior may seem, some sharks on earth employ a similar strategy in swimming
along the sandy floor near the shoreline in search of food, although they don’t possess
the extreme tunneling abilities of the Sand Shark.
A common target of the Sand Shark’s brutal ambushes swims overhead.
The Spadefish doesn’t look like much from most angles, but glimpse one from above and
you’ll spot its defining feature: a single, cyclopean eye.
Closer analysis of the Spadefish suggests it feeds on the sea floor, and its single
eye allows the spadefish to spot predators above it.
Its mottled green coloration suggests it normally hides among sea grasses like many fish do
on earth.
When a Spadefish wanders onto the Grassy Plateaus, however, it is hopelessly exposed…
On the far side of the Grassy Plateau, what appear to be tiny floating islands hang miraculously
in the water.
Upon closer inspection, these chunks of rock are all suspended by colonies of the same,
curious lifeform: the Floaters.
Transparent, gelatinous blobs, floaters are at once oddly beautiful, and a little silly
looking.
Analysis of these creatures reveal they’re actually multiple microorganisms living in
symbiosis, which we can compare to some deep-sea species of jellyfish.
The floater’s ability to suspend such heavy objects, however, remains something of a mystery.
Swimming close by the floating islands is a distant relative of the peeper called the
Reginald.
The entire back end of these oddly-named fellows is composed of one large fin, and the fin’s
bright coloration appears to be part of a mating ritual.
Biologists believe the Reginald filters algae and other plant material from the water via
four gill-like, forward-facing orifices.
While this is a noteworthy adaptation, something looming behind the Reginald demands our attention.
In the abyss beyond the edge of the plateau, the largest organism we’ve yet to glimpse
calls out through the deep.
This is a Reefback: a leviathan-class organism that exceeds lengths of 220 feet or 70 meters,
and is, thankfully, quite friendly.
Swimming closer to these gentle giants, we can see they’re unlike any lifeform we’ve
yet to glimpse.
Possessing a thick exoskeleton, their shells have become an oasis of life.
Adult Reefbacks can support mini-ecosystems on their back: including many types of coral
and small fish.
And nearby this adult is its baby: a much smaller creature whose shell is not yet ready
to support an ecosystem like its parent’s.
I confess I spent some time just watching these creatures drift in their pods, listening
to them call out to each other with complex sounds that suggest a surprising amount of
intelligence.
With the sun now getting low, it’s time to venture
deeper into the abyss, and enter the foreboding final biome of the Dunes.
In this fast, empty expanse, life often flocks near hydrothermal vents.
These great fissures on the sea floor release a rich chemical soup into the water, much
like those that support life in the depths of Earth’s oceans.
But it’s not life among the vents that concerns me…
A terrifying roar comes from above.
A Reaper Leviathan strikes out in the abyss.
This aggressive apex predator possesses four mandibles at the front of its maw to drag
in large prey.
And at 180 feet, or 55 meters in length, a hungry Reaper Leviathan can take down almost
anything.
Analysis of the organism’s biology suggests the deep roar emitted by the Reaper is a form
of sonar – meaning if you can hear it, the reaper can see you.
Thankfully, it seems this Reaper isn’t hungry.
And as I watch the deadly leviathan vanish into the darkness, I realize I’ve done enough
field work for the day…
The sun has now set on 4546B.
Yet the wonders of this planet continue, as in the low light, various regions of the sea
are transformed by stunning displays of bioluminescence.
Even the Reefback pod from earlier is now giving off a striking glow.
This eerie beauty suggests the many hidden wonders we have yet to see beneath the surface.
We’ll venture farther into the depths in Part Two of the Biology of Subnautica, investigating
the larger, more extreme, and often more dangerous life of the deeper biomes.
For now, though, our journey is at its end.
As always, thanks for watching.
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