Every Subnautica Creature Explained by a Marine Biologist

Added: 2026-05-14

[00:00:26]Hello everyone. Welcome to the longest video I have ever made by far and probably the longest one I will ever make. Today I'm going to put my marine science degree to the test and take a look at every single animal in Subnautica. This video came highly, highly requested after my video reviewing the game from a scientific standpoint. So to everyone who wanted that, thanks for inspiring this behemoth of a video. For this video, I will only be discussing the animals in the base game. No flora and nothing from below zero. Maybe I'll do a video in the future. Who knows? Furthermore, the order I talk about them in will be when they appear in the fauna page of the Subnautica wiki. So, it will be carnivores first, then herbivores, scavengers, and parasites, and finally your questions about each Leviathan, and each segment will be in alphabetical order. Quick disclaimer, I already have videos on each Leviathan, so if you want to hear my thoughts on them, be sure to check those out first, then come back here to have any potential questions answered. I'll put timestamps in the description for each segment to make it easier for anyone looking for a specific species. With that, I've already made you guys wait a year and a half for this video, and I'm not going to make you wait any longer. Let's do it.

[00:01:46]The amp eel is a deep water carnivore that clearly takes heavy inspiration from the real life electric eel. I mentioned it in the Subnautica review and it should be pretty obvious, but the amount of electricity required for it to be visible across the amp eel's body is absurd and would be doing way more than 15 damage. It should kill you without question. It does however allow them to blend into the environments they most frequent. Those being the bulb zone and blood kelp trench. It may be an upper trophic level predator, but it always helps if prey doesn't know you're there.

[00:02:21]And even a creature this big sometimes needs to hide from something. The electricity isn't just a gimmick, however, as it does have some pretty neat interactions with another animal we will discuss later. The biter is a small predator that can often be seen hunting in pairs or groups in a variety of environments, but most commonly in the grassy plateaus and jelly shroom caves.

[00:02:44]The red dorsom and bluish white ventrum are an excellent example of counter shading, a kind of camouflage seen in the ocean in which an organism is harder to see from both above and below. Look at a great white shark. On top, it's gray, meaning a poor seal on the surface will have a hard time seeing its imminent doom coming for it. From below, it's white, blending into the sunlit waters above. The biter blends into the blood grass from above, and the stripes help to break up its form. The light belly makes it hard to spot from below as well. Its teeth are similar to a piranhas in that they are designed like steak knives, sharp, thick, and serrated, allowing the biter to tear off chunks of prey that would otherwise be too large to swallow whole. The blighter functions identically in the game to the biter, offering only environmental flavor, as it's found in deep water environments like the blood kelp zone and caves. Its body is much darker in color like the caves it dwells in, and the low light has resulted in a large reduction in its vision, likely only able to tell light from dark. The stock on its head, which functions similarly to a nose for the biter, is now bioluminescent, making this little terror into Subnautica's version of an angler fish.

[00:04:00]At least I thought that's how it would function until I looked a little closer and noticed the lur was red. This is important because the color red disappears very high up in the water column and so many deep water species cannot detect it and the bladers mostly useless eyes most likely retained at least that ability when evolving to live in the deep. On Earth, certain dragonfish species use red spotlights under their eyes to [music] seek out prey in a similar fashion. On top of this, many deep sea creatures actually have red pigmentation to blend in, but when illuminated by the dragonfish, they are extremely noticeable. The dragonfish, however, remains undetected to the [music] prey or its own potential predators. The blader likely utilizes the same strategy, but without the other features seen on angler fish and dragon fish on Earth, such as a large mouth to eat anything it [music] finds. I can't imagine the blader is too effective in that niche. More likely, it functions as a deep sea micro predator, such as the cookie cutter shark, only taking chunks out of larger animals to eat without actually killing them. The bone shark is an armored carnivore that lives in a huge variety of environments, indicating it is a very successful [music] species, and it's not hard to see why. Armored plates cover its body, a fairly large size, very high levels of aggression, as it will chase the player for long periods of time, and likely being a pack hunter, as evidenced by its social tendencies, ensure that most creatures will think twice before coming near their territory. It reminds me a lot of Dunliosis, which was another real life armored fish that ruled the seas of the Deonian. And I'd wager I guess Unknown Worlds drew some inspiration from it in the creation of the bone shark. The crab snake is what's known as a trogabyte, which means that it lives exclusively in caves. Specifically, it evolved to live in the jelly shroom caves. And the reason we don't see it in any other locations in Subnautica is because they would likely have to evolve into an entirely new species in order to survive outside. They've got the same counterhading we discussed with the biter and we'll see more of throughout the video.

[00:06:12]And they're also a great example of mutualism, a form of symbiosis. For those that are unaware, symbiosis is a close physical relationship between two organisms. And there are three kinds.

[00:06:24]Commensalism is where one organism benefits and the other is unaffected.

[00:06:28]Think of a bird making its nest in a tree. The tree is completely unaffected.

[00:06:33]However, the bird now has a place to lay its eggs that's safe from groundbased predators. Parasetism has one species benefiting while the other is harmed.

[00:06:43]Think of my video on the tongue eating parasite. Samatha benefits by drinking the fish's blood and the fish is harmed because it gets its blood drunk. Oh, and it loses its tongue. Mutualism sees both species benefiting. Think of a clown fish and anemone. The anemone uses its stinging tentacles to protect the clown fish from predators like a grouper. The clown fish will also fend off the anemone's predators such as sea turtles which are unharmed by its sting. In a similar way, the crabnake defends the jelly shrooms by eating the herbivores that would likely graze on the shrooms.

[00:07:17]The drlli shrooms don't exactly protect the crab snakes from predators as they are the apex predator within the caves.

[00:07:24]However, they provide an excellent location for the crabnake to ambush prey and to lay its eggs safe from any potential egg thieves. Finally, the crabnake and jelly shroom are an instance of something called co-evolution. This is when two organisms evolve in close association with one another so as to best optimize their relationship. Think of flowers evolving to attract only one species of pollinator so it doesn't get pollen from any other species by accident. The idea of an evolutionary arms race is co-evolution on a grand scale with organisms all across an ecosystem evolving to best survive in a world with all of the others. The crab snakes that thrived and were able to reproduce were the ones that could live in the caves and the jelly shrooms. And the shrooms that reproduced were the ones to provide a safe place for the crabnake to live. I used to dislike the crab squid for its EMP because I figured it was only a gameplay mechanic and had no basis in evolutionary biology. However, they have been in an evolutionary arms race with the amp eel using the EMP to negate the ampiel shock. This would also explain why it attacks the player and submarines as it can likely detect the electricity and sees the lights from tools and subs, mistaking them for an ampiel. That co-evolution I talked about with the crab snake is on full display with these two as the amp eel will likely continue to evolve a more powerful shock or perhaps a stronger bite while the crab squid strengthens its EMP or longer limbs to keep the ampiel at bay. Outside of the EMP, I really like how the crab squid has two modes of movement. It can swim around like other animals but also use its legs for walking on the seafloor and cave walls. It reminds me a lot of a flying gonard whose rays on the pictorial fins have evolved into gudimeamentary legs. They blend in well with the membrane trees and [music] anchor pods of the Grand Reef, the most common place to encounter them, at least in my experience. I was way too mean to the crash fish in my review. I said that it didn't make any sense because it blows itself up and I had moved on after about 10 [music] seconds. That did not sit right with a lot of you guys. I had a ton of comments providing hypothesis as to why they would explode. And they got me thinking. Yes, it's true that certain species of ants do something similar, and bees can only sting once before they die. But the difference is that the members of a colony that do so are infertile and cannot reproduce. Only the queen and drones reproduce, so the workers and soldiers can give their lives as their genes are identical to each others and do not need to be spread. However, there is another reproductive pattern that could explain the crash fish's explosive tendencies.

[00:10:09]Seminal parody is when an organism only reproduces once in life before dying, using up all its energy in the act to maximize the number of offspring it has.

[00:10:19]I explained why this reproductive strategy evolved while addressing the crash fish during my playthrough of the base game, and I'll play that clip now.

[00:10:27]If a salmon lays a million eggs and dies, that's 1 million children. But if it lays 900,000 eggs and returns to the ocean, but only has a 1% chance of reproducing again, and that's being generous, we multiply that 900,000 by 01 and get 9,000.

[00:10:47]Adding that to the previous 900,000 and we see the 1 million eggs before death is still more worthwhile. Because remember that all life wants to maximize the number of offspring it has while alive. I used salmon as an example because it's the one most people would be familiar with, but I think the crash fish bears a closer resemblance to the octopus in this respect. Octopuses, yes, that is the correct plural form of octopus, only live a year or two. After a male and female copulate, the male leaves and dies. The female lays her eggs in a crevice somewhere and washes over them, defending them from potential predators. She never leaves them, not even to eat. By the time the eggs hatch, she is so starved and drained that she cannot keep herself alive, giving her life to ensure the survival of her offspring. I imagine the crash has a similar strategy, laying its eggs in the sulfur plant and watching over them.

[00:11:45]They have a mutual relationship with the plant benefiting by feeding off of the crash fish's excrement and the crash fish having its eggs protected. You can find eggs laying around, but I chalk that up as for the sake of gameplay.

[00:11:59]Now, as for the explosion, I'm not entirely sure how the crash fish accomplishes this. The exploding ants in real life don't actually explode in the sense of a big fireball, but rather rupture their muscles and release a toxin to ward off threats. The crash fish is noted as having a high concentration of sulfur in its body, which is explosive. And organisms on Earth have numerous oxidizing agents in their bodies that could cause sulfur to react explosively. So, it's definitely not out of the realm of possibility. The lava lizard is found in the heart of the crater, covering itself in molten rock as armor. This is puzzling to me. A number of you guys brought to my attention the scalyfoot gastropod which I did not know about previously.

[00:12:47]The middle layer of their shell is the perryostricum and the outer and inner layers are iron sulfide and oraggonite respectively instead of the typical perryostricum on the outer part of a mollisk shell with the prismatic layer in the middle and nreus on the inside.

[00:13:03]At least I can't find any information saying it has a prismatic and nicous layer the way that other shelled mollisks do. However, these unique layers are produced by the snail itself, not taken directly from the environment.

[00:13:18]They allow the snail to live in the high heat environments they are found in. The lava lizard has a thick layer of scar tissue on its back that lets it resist the heat of the molted rock it covers itself with. Think of having calluses on your hands, making a hot kitchen pan not burn you as much. I'm not sure how the lava doesn't burn right through their scar tissue, or how the rest of its body doesn't get immediately incinerated when it buries itself in lava, but whatever.

[00:13:50]The Mesmer functions almost identically to a cuttlefish. No, not the one from the game, the real one. These sephalopods flash hypnotizing colors and patterns across their body as they move towards mesmerized crustaceations before shooting their tentacles out and grabbing them.

[00:14:07]>> I saw a documentary to terrify >> the messmer in game does the same thing to the player making them hallucinate hearing the PDA tell them to approach the Mesmer when scanned. It even alters the PDA's entry which is a pretty nice touch even if it doesn't make much sense. I just wish it did something that wasn't the same as a cuttlefish because it does feel kind of like a carbon copy.

[00:14:31]As unique as it may seem, it's honestly the closest to a real life animal out of any in-game carnivore in my opinion, which paradoxically takes away from the coolness factor. The river prowler is a large eelike predator found in the Lost River. It has a skeletal appearance which is pretty on theme for the other creatures in the river like the ghost leviathan and the spine fish. Can't see its internal organs which might mean they are translucent. And it completes the look of a swimming skeleton. This might be useful in staying safe from the ghost leviathan because the river has bones everywhere and the river prowler might be mistaken for a dead fish.

[00:15:14]The sand shark is found most often in the grassy plateaus, typically buried in the sediment and ambushing prey. It appears to have small leg-like appendages on its vententral side that likely help it move within the substrate. Its flat body would help it cut through the sand as well. However, the sand shark swims side to side when not input suit, which means the thin side is what is catching the water to swim. And you can see how slow it makes a sand shark move. For example, flatfish on Earth such as flounder and halibit swim up and down relative to the water column because as they grow, their eyes and mouth move to one side of their body, allowing them to have all the important bits facing the sky. But when the sand shark begins chasing prey, it can be seen attempting to swim up and down in a very awkward motion as it tries to utilize the flat part of its body to catch in the water better and speed itself up. Pretty nice touch.

[00:16:13]Stalkers are likely the first predator we all encountered. Kind of dumb and goofy looking, but they're charming in a way. They have presumably infinitely growing teeth much like rodents and the babusa on earth and therefore need to keep them from getting too large and problematic. They do this by grabbing metallic stuff like metal salvage, titanium, silver, and camera drones. And they seem to bring it to the same place.

[00:16:39]Despite their dopey appearance, they are likely fairly smart. They swim together and seem to stockpile metal together, like a communal pile of metal that they can all share.

[00:16:50]You can also make them temporarily passive by giving them a peeper, further displaying their intelligence by understanding that the player may be a friend. I don't really know if I should even talk about the warper. It's not native to 4546b and it's basically a Frankenstein's monster of a creature stitched together from multiple other organisms, potentially not even from the same planet, and it's a dirty cyborg clanker. They're super cool and intimidating though. I like them. That about does it for the carnivores. Let's talk about the herbivores. Just a heads up, I will have significantly less to say about most of them compared to the carnivores, as a lot of them are just this fish can be cooked and just add flavor to their respective environments, which is a good thing. Starting out with the bladder fish. It's super unique in that it can be used not just as food, but as water, too. You can eat it raw to get oxygen, which I think is just for gameplay purposes, but the giant membranes on its dorsal and ventral side are of interest to me. You see, the bladderfish has no mouth. You may be wondering how it would feed or even breathe. That's where the membranes come in. Every organism breathes by diffusing oxygen across cell membranes. Your lungs have an absurd number of alvoli to increase surface area, thereby increasing the amount of oxygen you can absorb. On Earth, a film known as platyhelmentthyses, commonly known as flatworms, [music] have no lungs or gills. Instead, they have a very high surface area relative to their overall volume, courtesy of their flat body.

[00:18:26]Termarians are a class of flatworms that are almost all free living, whereas most flatworms are parasitic. And while they do breathe directly through their skin, they also have a mouth in the form of a ferinx on their vententral side. The bladderfish is apparently capable of filtering out organic particulate to eat through these membranes. And while I'm not entirely sure how it does this, as I can't think of any examples on Earth that do this, it is a very interesting concept. The boomerang is another small cookable fish found in the safe shallows. As you might expect, it is shaped like a boomerang and appears to have multiple planes of symmetry.

[00:19:03]Bilateralans on Earth, such as mollisks, arthropods, and vertebrates, have a plane of symmetry along their midsagittal plane, giving a mirror image of their left and right halves. The boomerang seems to have one not just here, but is a mirror image on the vertical plane as well, with the top and bottom half appearing identical. This extends to their digestive tract as the game states that it terminates at the ends of both cartilagynous fins. This split would likely have to happen early on in its embryionic development, presumably before the digestive system develops. The previously mentioned fila have a gastric stage in their development in which a continuous path emerges in a ball of cells forming the one-way digestive tract. The boomerang would have to have this path terminate at two different locations, something we do not see on Earth, but when discussing such an early stage of development, it may be entirely possible in an alien life form. The Crimson Ray is a large herbivore occurring in the lava zones.

[00:20:09]The PDA compares it to other scavengers, which makes me wonder why it wasn't classified with them, but here we are.

[00:20:16]As this is our first non-carnous species found in the lava zone, I want to introduce you all to a hypothesis I first talked about in my sea dragon leviathan video. I suspect that the species found in the lava zone all survive by eating molten rocks and a chemosynthesizing symbiotic bacteria living in their stomachs break these rocks down into something the host can eat. Basically, picture how a lykan works on Earth, but with the host animal being the fungus and the chemosynthetic bacteria taking the role of the photosynthetic algae. I realize this is kind of a cheap copout answer, but I'm really trying my best here. In real life, deep sea creatures are able to survive in the deep because of a phenomenon known as marine snow, in which dead organisms sink to the bottom, and much of it is eaten on the way down by the scavengers in the twilight and midnight zones of the ocean. However, the surface is not directly above the crimson rays habitat, and marine snow would have to travel through several kilometers of underwater caves to reach them. Long story short, I don't understand how any food makes it into the lava zone. You can expect me to have similar problems with the other animals living here. The game hypothesizes the cuttlefish might have been brought to 4546b from another planet, but personally, I think it's endemic. It shows a similar body plan to other creatures, those being the sea dragon and sea emperor in that it has a vertebrate-like anterior with sephalopod tentacles in its posterior as well as what appear to be the vestigial remnants of forward- facing limbs. It's listed as being highly intelligent as it will play with the player. Not much to say about this little cutie. The II is another cookable fish featuring two planes of symmetry. It's very slow as its eye makes it not very aerodynamic and it has small fins. The game says it's closely related to the peeper because they both have large eyes, but other than the two planes of symmetry, I do not see the resemblance. The size of an eye should be one of the last things used to determine common ancestry. Look at bush babies, great corned owls, giant squid, and swordfish. They all have huge eyes, but none of them are particularly close to each other on a phoggenetic tree.

[00:22:35]Their last common ancestor most definitely did not have giant eyes.

[00:22:40]Also, the II has its eye front and center, right in the middle of both planes of symmetry, whereas the peeper's eyes must have developed after the midsagittal plane of symmetry formed during embryionic development. If two organisms don't even have embryos that develop the same way, then they are very, very far removed from each other.

[00:23:00]The Gary fish is a cookable fish that doesn't really provide much sustenance.

[00:23:04]It has eye stalks that allow it to hide itself and still look out for predators like a shrimp. That's all I got. The gasopod is a weird sea cow looking creature with a bulbous tail section that excretes toxic gas pods when it feels threatened. It's a very cool addition to the game because I can't think of any other animals that have a chemical defense like this in Subnautica. The brine ring from Below Zero might be the closest example, but it just shoots super cooled salt water at the player in an offensive manner.

[00:23:34]Biologically speaking, I'm not sure why the gasopod releases the toxins as harmless pods at first that explode into a chemical deterrent, but I understand this was done for gameplay purposes to telegraph to the player that it's time to back up. The ghost ray is another large ray species. It appears semi-t translansucent in nature and found throughout the Lost River. The problems with a large non-predatory species living in a cave system do not necessarily apply to the Ghost Ray, however, as the Lost River has multiple entry points that would allow for the flow of water currents carrying marine snow into the river and providing sustenance to its denisens. Currents may exist within the lava zones as well, but the distance marine snow would have to travel is likely too great to sustain life in its current state in that environment. The see-through nature of the ghost rays is likely a defense mechanism to hide itself from the river prowlers and ghost leviathans that inhabit the river. It's also poisonous like the other rays, providing more protection from predators, even if it does still get attacked. The Hullfish has a large hole on its posterior half, as its name would imply. I'm not entirely sure at what stage of the whole fish's embryionic development this would originate, but we already talked about the boomerang with its double-ended digestive system, so it's not totally impossible. According to the PDA, it can also change the size of the hole for specific maneuvers.

[00:25:03]Sure, why not? The hoopfish is seen in shallow waters and also has large gaps in its body like the whole fish. I guess this is a common thing on 4546B.

[00:25:15]The PDA claims it doesn't swim like a regular fish. It instead, and I quote, alters the composition of the water in front of it, allowing it to sail into the low density space created. The only interpretation of this sentence that makes sense to me is that the hoopfish move through the water using a jet propulsion system like sephalopods on Earth. I imagine the hoops act like pipes, sucking in water at the front and squeezing it out near the codle fin to create forward thrust. According to the PDA, the hoverfish uses its pads to ionize the water around it in order to hover. As its name would imply, ionizing water splits the molecules apart and changes the pH. And I'm not quite sure how this helps the hoverfish, but sure, why not? I'll give them a pass just because I love them. Look at him. I would choose this guy over the cuttlefish every time. Jelly rays are almost the same as the ghost ray from earlier, but this time their fins are now more tendike. We can even see what appear to be the same tendrils in the Ghost Ray, except there are more of them. Not much to say here. The jelly ray is mostly just environmental flavor, and I am all for it. The Magmarang is the same thing as the Boomerang, but red and in the lava zone. The problems I have with it are that it appears virtually identical to the Boomerang, apart from color. This thing lives more than a kilometer below the surface and seems to have no apparent evolutionary adaptation to its high pressure environment. Typically, creatures at these depths will be a lot more squishy, slower moving, reduced eyes, and pale or red in color. Pale means no pigmentation, so less energy spent. And red light is absorbed quickly in the water column, so red pigmentation would hide an organism very well in the deep.

[00:27:08]To its credit, the magm bearing has both white and red coloration, which would be effective camouflage both inside and outside the lava zone, provided it remained at these depths. Other than that, the same problems that apply to the other lava zone creatures due to the magmarang as well. The oculus is another trogabyte living in the jelly shroom caves. It looks like the peeper, a creature it is closely related to, and lives near its reef dwelling counterpart. The primary difference is [music] its coloration. Instead of yellow eyes and a matte blue body, the Oculus has purple eyes and an iridescent blue body, which give it improved camouflage in its environment. Its posterior section also no longer resembles a tail, but instead looks like tendrils [music] for reasons I am unsure of. It fits the eerie cave vibe, and maybe it's meant to imitate the appearance of the drooping stingers.

[00:28:04]Overall, this is a pretty good job of taking a species from one environment and [music] changing it to better fit another. Something that was done less effectively with the Magmarang.

[00:28:14]And here we arrive at what is probably Subnautica's mascot, the peeper. Bright yellow eye and blue body make it easy to find both day and night. Arguably even easier at night because of the bioluminescent eyes, which doesn't really make sense to me. It's got a beak as a mouth, which is often seen on Earth by coralores, meaning an organism that eats coral. The codle fin, that's a fancy word meaning fish tail, is somewhat interesting in that the secondary dorsal fin, that's this one, and the anal fin, that's this one, seem to have taken its place. It reminds me not of any tios or rayfinn fish for that matter, but rather looks inspired by lobe fininn fish. You see most extent species of fish that just means not extinct are rayfinned fish. Rayfinn fish have fins with rays supporting them while lo have fleshy lobes instead. Loin fish are very common in the fossil record. However, today there are only represented by eight species. Six lung fish in fresh water and two celeracamps in marine environments. Here's what a gray fininn fish's codle fin could look like. And here's a codle fin of a loaf finin fish. Now you tell me which one looks more like the peeper. Just a side note on the lo fin fish. Don't feel bad for them and think they were an evolutionary failure. They certainly weren't. All land dwelling vertebrates that includes you and I evolved from them. The people can also carry enzyme 42. I don't know why. I guess for the convenience of the story. It is what it is. The grabbit ray is another example of environmental flavoring. Not able to be eaten or harm the player, but they've got a really nice color palette. It kind of reminds me of those turbolarians I mentioned earlier. Their ears are antenna that sense vibrations in the water, likely to alert it of the few predators it may have. I say few because like the other rays on planet 4546b, it has poisonous flesh, hence the bright colors. They also appear to have five gill slits, which is pretty standard among condries, aka sharks, gates, and rays. The latter being their inspiration. Despite the PDA labeling them as an herbivore, their shovel-like snout and mouth placement suggests to me that they're carnivores like raisin skates on Earth, digging in the substrate for stuff to eat. However, the game seems to label anything that can't hurt the player as an herbivore, and the PDA is more meant to tell the player what is safe and what to avoid. So, I get it. I have nothing new to say about the red II. Everything I could say about it was already explained with the regular II and Magmarang. I guess I could say this. If you were to fish one up, it would be a gruesome site. I can tell you from my job experience that when you pull up fish from the deep whose bodies are pressurized to live at extreme depths, bringing them to the surface will often cause their eyes to expand rapidly. Here's a rockfish that got hauled up on a commercial fishing vessel. Those eyes aren't supposed to look like that. I've seen fish that were hard to identify because their bodies exploded and ended up looking like popped balloons. And I can tell you with an eye as big as the red eye has, coming to the surface from more than a kilometer down is going to cause that eye to look like those on that rockfish if it doesn't pop on the way up from the abyss. On that pleasant note, let's move on. The reginald is said to be a distant relative of the peeper. This I can believe. The secondary dorsal and anal fin making up the peeper's tail appear to have joined in the Ginal's case. The only thing holding me back has to do with the Grenald's face and how the top is different from the bottom only having one true plane of symmetry as opposed to the peepers too. However, there are examples on Earth of animals evolving slightly different body structures on mirrored planes, such as a lobster having one claw for crushing and another for cutting. Another example being flatfish, which do not appear symmetrical at all.

[00:32:28]The Skyway is the only flying animal seen in the game, but we can deduce that it is likely not the only one to exist in 4546B's history. Flight is an extremely common trait in animals on Earth due to how effective it is for travel, escaping predators, and hunting.

[00:32:47]As I stated in my sea dragon and emperor video, there likely used to be a lot more land covering this planet and so flight would have almost inevitably evolved as it clearly did. The penguins likely share a common ancestor with the skyray as they have clear inspiration from penguins. The spade fish is another creature with gaps in its body like the whole fish and hoopish. only one eye that looks directly up to supposedly keep a lookout for potential predators, but based on where it can be found a lot of the time, I'd say it would be better to look down into the substrate for any lurking sand sharks. The game calls them herbivores, but again, I have to disagree. Those teeth are very sharp and would have an easier time eating meat.

[00:33:33]They've clearly got a tough body as hitting them with a sea moth will cause damage and their low food value tells me that most of the body is tough and otherwise inedible. The spine fish appears to be a deep water counterpart to the hoop fish. I really like the skeletal appearance of these guys. It helps them blend in with the other bones found in the lost river where they frequent. A similar strategy to the river prowies. However, what I can't quite explain is how they managed to make their way into the cave systems of sector zero despite seeming to be a sort of trogabite of the crater. That's it for the herors. Time to move on to scavengers and parasites. Just a quick note, none of the creatures the game labels as parasites actually fit that term, but I'll explain what I mean when we get to them. The amiioid is most definitely not a single-sellled organism. I know the game heavily implies that it is, but that causes some problems. For those wondering, the evidence I am using to label it as multisellular comes from its overall outward appearance, literally having what appear to be cells making up its skin. The main issue is in reference to how it feeds. Heterotrophic single-sellled organisms such as amiebas on Earth feed primarily by enveloping their prey which is most often another single-sellled organism forming a pocket around their body. And that pocket becomes an organel known as a food vacule which secrete digestive enzymes [music] that break down the organism into macroolelecules to be used by the amoeba. All of which is a process known as fagocytosis.

[00:35:12]Based on these tendrils, I would say the amiioid's body is too rigid to form the pseudapodia necessary for envelopment and rather digestive enzymes are secreted directly from the amiioid's epidermis onto whatever it is trying to eat. Food is then absorbed across the membrane into its body. This is similar to how sea stars feed, pushing their stomachs out of their body and secretreting digestive enzymes onto their prey. However, sea stars also reproduce sexually and lay eggs, allowing mutations to occur and for the population to evolve. Because the amiboid is a presumably multisellular animal, I have to imagine there is some way for it to reproduce sexually, not just splitting in two. Maybe it releases sperm and eggs into the water. Now, we've got the bleeders. I'm sure some of you are thinking I'll retract my previous statement of Subnotica not having any parasites. However, the bleeder is not a parasite. It instead falls under the category micro predator.

[00:36:15]Now, the difference between parasites and microp predators is that parasites will have a single host for their entire adult life and try their best to not kill that host. If you only have a single tapeworm inside you, you'll be fine. But a thousand will probably kill you. Now, I specified that adult parasites will only have one host because many parasites will move between hosts during different life stages, often manipulating their current host to get eaten by the next one. Point is, the environment a parasite lives in is the host. Whether it be on the skin or inside its body, they want you alive because they have no way out. And if you die, they go down with the Microp predators are carnivorous animals that feed on multiple creatures during their life. But unlike regular predators, they do not kill. Not out of the goodness of their hearts, but because they are smaller than their prey and simply cannot kill it. At least not alone.

[00:37:18]Female mosquitoes, bed bugs, fleas, leeches, and cookie cutter sharks are all examples of microp predators. And unlike parasites, microp predators do not live on or in a host. Their environment is the outside world. Fun tidbit, if you can call it fun. Microp predators themselves won't give you diseases. But many are vectors for parasites which cause disease, as many microp predators feed on blood and give the parasites with multiple hosts an easy way into their next host. Anyway, back to Subnautica. We can see bleeders swimming around freely in the water and will attack both the player and any other creatures. It drinks blood from its prey and moves on after feeding, meeting all the prerequisites to make it a micro predator. Now, I get why it feeds on the player. We are a living thing after all. But I can't imagine we would be very good to feed on. The bleeder evolved to drink blood from creatures on 4546B, which all have yellow blood, presumably placed on something other than iron.

[00:38:23]It's not just feeding on our hemoglobin.

[00:38:26]It's after all the nutrients as well. I just don't think our blood would be too healthy. Blood crawlers stand out from their shallow water cousins because of their long legs, pale pigmentation, [music] and the depth at which they are encountered. They remind me a lot of lithod crabs. Think king crabs. Spiky long legs and a deep water species.

[00:38:48]Something tells me there was some amount of inspiration drawn from there. But what I don't understand is why the blood crawler moves so much faster than the cave crawler. Also, why does a creature that lives in such [music] deep depth have eyes? Meanwhile, its sunlit shallow water relative doesn't. Oh, by the way, this big thing in the center of its torso isn't an eye. It's its breathing apparatus. I do really like how well it blends into the blood cel zone, and it looks similar to the skeletons of the lost river as well, serving as fairly effective camouflage. Cave crawlers might be the most [music] irritating creatures in the game. There you are trying to get loot in the Dassi Island base, and you're constantly getting attacked by these buggers. Or you roll up to the Aurora, sneaking past, you know who, and these guys are trying to get in your way. Anyway, they're not too much different from the blood crawlers other than having shorter legs, no eyes, move slower, and a little more colorful.

[00:39:49]I genuinely do not understand the floater. It feeds off of rocks like some bacteria do. But what's the point of floating? It's not even the floater itself. [music] This translucent outer membrane is a sheet of colonial microorganisms that make it float. But what purpose does it serve? If I ate rocks, I would want to sink to the bottom. You know, where the rocks are.

[00:40:12]But obviously, there's some benefit. So, let's try to hypothesize what that might be.

[00:40:19]Well, it does feed on other things besides rocks, such as other animals, like reefbacks. And reefbacks are found near the surface. So, maybe that's why they float. They hang around the surface, get picked up by reefbacks, which carry them around the planet to spread around. Of course, that doesn't explain the ancient floater. The lava larva is another creature I need to apologize to. For a long time, I assumed there was no way they could survive [music] in the way the game claims.

[00:40:48]However, it turns out there are actually certain species of bacteria that fuel their metabolism with electricity rather than sunlight or high heat.

[00:40:58]Appropriately, these bacteria also live around hydrothermal vents. And a similar organism likely lives inside the lava larvae alongside the chemosynthetic rock eaters I introduced in my sea dragon video. Because of this, its normal niche would be as a bottom of the trophic level consumer rather than a parasite, which is why I don't think there are any true parasites in the game. However, in the case of the player, I would call them a microp predator, as they are free living, but will feed upon the electricity of the submarines. Also, it's not really a larvae. At least, we've never seen anything in the game that appears as a more mature version of the larvae, and it's just got its name because it looks like a grub. Speaking of grubs, the rock grub is by far the smallest creature in the game.

[00:41:48]Allegedly, it's a close relative of the sand shark, which I can almost believe.

[00:41:54]The segmented body and limb structure tell me it's related, but the problem is the codle [music] fin, aka its tail. The shape and location tell me the rock grub's body moves vertically, while as previously discussed, the sand shark's body moves horizontally. The way muscles move is a pretty big indicator as to what creatures are related. More likely, it's an instance of convergent evolution. However, I will concede that it may at least be a vertebrate, [music] putting it in the same film as a sand shark. Other than that, not much to say.

[00:42:29]It's nice seeing a creature that's so small when almost everything else is gigantic.

[00:42:35]Lastly, we have the shuttle bug. I love this guy for the fact that it does nothing. It provides nothing for the player and yet it is in the game purely as environmental flavor. Biologically speaking, it has tralial symmetry, meaning three sides are symmetrical around its center.

[00:42:56]Nothing alive on Earth today has this body plan, but there is an extinct film known as trilobzoa that was around during the edi with triradial symmetry.

[00:43:07]So, it's cool seeing them get some honorary attention. It's got these legs for walking or jumping and these mandible fin things that help it feed or swim. Not really anything else to say. I love these guys. That's all the scavengers, parasites, and other miscellaneous creatures. Time to move on to what most of you are all probably here for. The Leviathans is what I would be saying if I stuck with the original plan for this video.

[00:43:37]But after I gave the Ghost Leviathan its own video, I decided to do the same with all the others. So, if you haven't watched those, make sure to do so now.

[00:43:45]then come back to this video. For those of you who have already seen them, however, this next section is going to be dedicated to addressing the most frequently asked questions and comments I got about each Leviathan. A lot of you pointed out that the ghost leviathan, as well as all the other creatures in the game, are hermaphroditic.

[00:44:03]This was a big oversight on my part. I was going off of faulty information from when I thought the Leviathans all had male and female sexes, but I must have misremembered something in the past. The ghost leviathan does not have enough eggs in a clutch to make a semolaris lifestyle work, particularly with the juveniles being cannibals. While I can see a point, I don't think the first ghost leviathan to hatch would eat all the eggs inside the cove tree, as it would be too small to do so. Instead, it would immediately swim off and start eating other stuff. Furthermore, I don't think the eggs we see are the only ones in the cove tree. Most likely, there are others inside, waiting for the largest ones to rupture the tree and allow room for them to grow. Different eggs from the same clutch most likely take different amounts of time to [music] grow, depending on how long it takes them to get nutrients from the cove tree. More likely, they hatch in small groups with only a couple surviving each hatching spree. The ones that do grow quickly and have virtually no predators, meaning they would have a very high survival rate after a relatively short period of time, provided they can make it that long. Why are there no ghost leviathans in sector zero? A couple reasons. First, we don't see a cove tree anywhere around sector 0. I hypothesize that the ghost leviathans require a cove tree in order to lay their eggs. So no cove tree means no ghost leviathans and therefore none would return to sector zero after finding a mate. Secondly, the void chellisserates. While they are significantly smaller than an adult ghost leviathan, their enormous jaws would have no trouble ripping apart the ghost's presumably squishy flesh. The ghost leviathan could consider the entire void its territory, therefore creating another potential solution to the food problem. I wholeheartedly agree. The ghosts could voyage all across the void thinking of it as their territory. The reason we see them right around the crater could just be because that's where they happen to be at that particular time. The PDA says that juveniles only eat other ghost leviathans and herbivores, not river prowlers. Yes, you are correct. It does say that and I was making an assumption.

[00:46:16]However, my assumption is based on the fact that we see it attacking river prowlers. The PDA entry is only going off of a sample size of one. as you can only scan one juvenile during gameplay.

[00:46:28]It could be that the juvenile we scan in game just didn't happen to be digesting any river prowlers when it was scanned and therefore the PDA wouldn't know it ate them. What would happen if the low phosphate regions of the ocean had phosphate dumped into them? Thank you for asking this. It's nice to see questions about pure science. It lets me know my teaching is actually comprehensible. Anyway, this is actually a real solution that has been proposed to increase phytolanton production and therefore take out more carbon dioxide from the atmosphere to combat climate change. However, the concern and what would likely happen if phosphate or any nutrients for that matter were dumped in excessive amounts in the ocean would be utrification in which phytolankton would have massive blooms taking [music] oxygen out of the water and making it impossible for animals to survive. And finally, the ghost leviathan never actually loses its territorial nature, even when venturing out into the void in search of a mate, because there would be little to no evolutionary pressure to lose it. Well, do 29, you say you're not a biologist, but you definitely should become one. You have the right thought process. It actually would be useful for the Ghost Leviathans to keep their territorial tendencies in the long run.

[00:47:42]While out in the void, there wouldn't be anything around aside from maybe a sea emperor or reef back, but the odds of running into one would be pretty low. So whether or not the ghost remained territorial wouldn't matter. However, when they return to the cove tree to lay and guard their eggs, being territorial would be extremely useful, as it would be the driving force to protect their eggs, as well as just general parental instinct. The reaper's red dorsome may actually appear a different color to the creatures of 4546b.

[00:48:13]Yes, it would. Now, it was pointed out that tiger's prey can't see the color orange, or at least can't tell the difference between orange and green, and so the tiger would appear green and black, therefore blending in with its environment. While this is an analogous concept, the Reaper would simply appear a different color because red light does not penetrate deep into the water, and unless the creatures in question had flashlights, they wouldn't see the red pigmentation.

[00:48:42]I didn't mention that the Reaper Leviathan is not at the top trophic level of the crater as it's eaten by the sea dragon. I definitely should have done this, but in all fairness, I talked about that in the sea dragons video. The reaper's mandibles should be tucked further back on their body for improved hydrodnamics.

[00:49:01]While it definitely would help the reaper swim faster, I don't think that the reaper is actually a predator that chases down its prey. Rather, it sneaks up on it. I pointed out a few reasons in the video why the reaper is so stealthy.

[00:49:13]Even the PDA mentions that it ambushes prey from behind. And so, I think it utilizes this to get within grabbing distance. And the mandibles being front and center allow it to make faster grabs. The reaper is a biological impossibility because of their buoyancy.

[00:49:29]The PDA says the reaper is almost all muscle and muscle is denser than water.

[00:49:34]Hippos are mostly muscle and they sink and so presumably the Reaper would sink.

[00:49:39]Based on the game's description, yes, I agree the Reaper couldn't exist because it would sink. However, there must be some kind of swim bladder in its body that we just don't see in game. Finally, the Reaper and Stalker are likely related. I agree, not necessarily because of their crest, but due to their bony fins and muscles. Both the Reaper and Stalker appear to have fleshy [clears throat] fins, and they both swim by moving their bodies vertically. A big indicator of Comet's ancestry is the way an animal moves. So, I definitely agree that reapers and stalkers are related.

[00:50:13]At least, they're closer to each other than the side to side swimmers, like the sand shark or river prowler. Nobody had any questions about the reef back. I guess that's a good thing in its own way. makes me feel like I got everything right. I'm particularly happy it passed alien planettology smell test as they're a lot better at planetary science than me. This next one is for both the sea dragon and emperor. They both have necks which is more evidence towards them sharing a terrestrial past. Absolutely.

[00:50:42]Some more evidence I forgot to include in the video. Eyelids. We can see them blinking. And this isn't like some sharks having nictitating membranes.

[00:50:50]This is actually blinking like what you and I do to rehydrate our eyes.

[00:50:55]Something that wouldn't need to evolve in a species that always lived in the water. So yeah, these two definitely have landbased ancestry. Could the rocks eaten by the sea dragon be gastroliths to help with digestion? Yes, they definitely could, but I wouldn't know how to go about proving it. Could the player be telepathic instead of the sea emperor? Yeah, I guess we could have some sort of brain chip. And the precursors could have put something in the Sea Emperor as well. And now those two technologies are allowing us to speak with one another. The Sea Emperors may have cultivated life on the crater.

[00:51:32]Now that you mentioned it, that's a really good point. You're right that they're smart enough to do it. And when the Kura bacterium came to 4546b, it may have wiped out the flora species on larger seamounts that would have had a more realistic spread between the biomes. So, the emperors brought them to the crater in a sort of swallbud global seed vault type situation. Sea tredder feces is a very good fertilizer.

[00:51:56]I cannot believe I didn't mention that in the video. I was thinking about it when I wrote the script and somehow I forgot. Yes, it absolutely is. And it's crucial in allowing the plant species it eats to spring back up. There's a reason it's the best fuel source for the bioreactor. And lastly, the sea treader might be related to the shuttle bug.

[00:52:16]Unfortunately, I'm going to have to disagree with you on that one. While they both have three legs at first appearance, the sea treader actually only has two with the one in front being a long trunk used for feeding. The sea treaders have bilateral symmetry like most of the other games creatures, while the shuttle bug has trial symmetry.

[00:52:35]That's not to say the sea tredder has no close relatives. However, the tri valve in Below Zero is another species with a tough exoskeleton that appears to have legike fins. And with that, I have covered every single creature in Subnautica's base game. It's been a long time coming, and I actually can't believe it's really over. If you enjoyed, a like and a sub go a long way.

[00:52:59]Now, I should probably wrap this up and get to sleep. I'll need a good night's rest since I'll be playing Subnotica 2 all day when it comes out tomorrow. But if it's May 14th and you're watching this still, what are you doing? Sonic 2 is out. Go play it. Anyway, that's all I got for you guys today. You all have yourselves a good one, and I hope you learned something.