Sea Dragon (and Emperor) Leviathan FULL BIOLOGICAL BREAKDOWN: Marine Biologist Explains

Added: 2026-05-10

[00:00:02]Hello everyone. I need to come clean with you about this video. Up until this point, I have made it my goal to rationalize the existence of every creature in Subnautica. And so far, I think I've been able to do that. But with the sea dragon, I'm not entirely sure I can. I did my best here, but with a creature like the sea dragon, there's only so much I can do. Also, because of how similar the sea dragon and sea emperor Leviathans are, I decided to make this a combination video and talk about both species as my thoughts on much of their physical attributes remain the same between the two. Anyway, let's get into it.

[00:00:44]To start, let's discuss the features we see both species share. First and foremost are their bizarre half vertebrate, half invertebrate style body. At least that's how it appears at first glance. From the front, they almost look like dinosaurs with both having a large bony head. The sea dragon skull appears very similar to that of a therapod and seems to have been heavily inspired by the T-Rex. The sea emperor's head isn't nearly as predatory in appearance, but is evidently still of close relation. They also appear to have foil limbs, which for me is an extremely bizarre choice on Earth. The kind of foil limbs we see in the sea dragon and emperor evolved in vertebrates once they began to walk on land so as to better support their bodies. Fortunately for us, a wellpreserved seadragon skeleton is present in game in the Lost River Junction. And based on their close relation, the things we can infer about the sea dragon skeleton can likely also be said about the emperor. The skull appears fused to the backbones, likely limiting its head movement. We can see the rest of the skeleton appears armored which matches the profile of the sea emperor. However, with the emperor, the skeletal armor appears to be on the outside of its body like a turtle. And while the sea dragon appears to almost have hands at the end of its forlims, the sea emperor does not. I believe this ties into their diets. While the sea dragon lives in the volcanic core of the crater, eating everything from crimson rays to the occasional reaper leviathan, the sea emperor's natural habitat is the void around the crater and far beyond, much like where I believe the reefback and ghost leviathans reside, and it feeds exclusively on plankton. For an enormous apex predator to hunt agile eel-like prey such as the reaper, the sea dragon would likely benefit from large foils for both agility and the ability to grab onto their prey and sink their teeth into them. For the former point, the foil limbs would likely not be as effective at helping the dragon turn as it would be if it had giant fins, but are much more beneficial on the latter point. However, for the sea emperor, it has no need to grab on to prey and so would not need these foil limbs for grabbing. That's why they appear to be a little bit more finlike and will likely continue to reduce themselves down further as the species continues to evolve into what we see in whales today. You see, we have a real life caid that parallels the dragon and emperor sitations. And here comes the really, really big kicker of the video that I'm sure everyone is going to have a big problem with and voice their thoughts on. I think that whatever common ancestor the sea dragon and sea emperor had tens or potentially hundreds of millions of years in the past lived at least partially on land.

[00:03:48]Don't click off the video. Just let me explain for a couple minutes. I'm not crazy. I swear this will all make sense if you let me show you my evidence. This unassuming mammal I'm showing you now has a name. Pachyetus.

[00:04:06]Some of you can probably tell where this is going. It was a small mammal that lived near water a few dozen million years ago. It hunted fish and other small aquatic prey. And it even got some representation in one of my favorite games, Fossil Fighters. Now, Pakisetus here is an extremely important species in the fossil record, as it is the common ancestor from which all sitations evolved. Citations, for those who don't know, are dolphins, whales, and porpuses. Pachy's descendants continued to hunt in the water with the most capable individuals surviving to reproduce and pass down their aquatic hunting abilities to their children. And now 50 million years later, we have the largest creatures to ever call Earth their home. If we look at the skeleton of, let's say, a blue whale and compare it to the sea dragon skeleton, the similarities should jump out at you.

[00:05:04]While modern whales have pectoral flippers, at the skeletal level, we can still see the same bones found in turtles, dolphins, horses, humans, birds, bats, and nearly all other terrestrial vertebrates. Each of these species uses the bones differently, with turtles and dolphins both using them for swimming, just in very different ways.

[00:05:26]Horses use them to run, humans use them as hands for grabbing, and with our ancestors, climbing trees. Birds and bats both fly with wings, but the bones in their wings appear very different despite accomplishing the same goal. To top it all off, some citations still have visible hind limb bones. But of course, we don't see these hind limbs, and the bones are vestigial. Again, not all citations have this, meaning the skeletons of those that do are likely to lose them in the relatively near future.

[00:05:58]In this case, that near future refers to a couple million years. I suspect that in 4546b's distant past, there was a lot more land than there is now, and terrestrial life was significantly more diverse than what we see in the present day. But as land masses shrank over millions of years, previously terrestrial species evolved to become semi-aquatic, then fully aquatic. Oh, and the dragon and emperor aren't the only examples we have of this. The sea monkey in Below Zero retains the same forms, but instead uses them for grabbing things. Also, that one fossil with the weird arms and armored body.

[00:06:40]But there's a couple problems. Where do these tentacles come from? On Earth, we only see tentacles on invertebrates.

[00:06:48]Fortunately, there's a relatively simple answer. The dragon and emperor had more time to evolve from their land-based ancestor than modern citations did from Pakisetus. While the blue whale's back half is little more than vertebra, its digital counterparts have had potentially tens of millions of years longer to evolve and instead opted for a more tentacley look. Tentacles can still provide ample propulsion in the water and allow the animal to remain quite agile. The other issue is the fact that all the species mentioned breathe underwater, presumably with some structure analogous to gills. There are no animals on Earth that evolved to breathe underwater after having a fully to terrestrial lifestyle. So, it's possible whatever common ancestor these fourlimmed creatures shared lived in coastal areas, never fully living on land and always having to go back to the sea to breathe. It may have emerged for short periods to feed on beach dwellers before returning to the water. Now, with all that out of the way, let's take a look at the differences between the sea dragon and emperor. Starting with the fireb breathing fiend.

[00:08:07]The only thing I really want to discuss with the sea dragon is the fact that it breathes fire. What it's actually doing is taking in molten rock and spitting it out at prey, likely to severely injure or kill it and allow the dragon an easy meal. Of course, that only answers the why, but not the how. And for a very long time, I've struggled with answering the how until it came to me randomly as I lay awake one night and had to write it down. They eat the rocks for food.

[00:08:43]Okay, he's gone. He's lost it. It's over.

[00:08:44]>> I know that sounds completely insane, and for the most part, it is. Look, I'm not saying it makes complete sense, but nothing I've been able to come up with for the year and a half I've tried to rationalize this stupid animal works perfectly. Anyway, it's able to extract nutrients from the rock because of a mutual symbiotic relationship it has with an organism living in its gut. In fact, I think most if not all the species found in the lava zone have this partner. On Earth, lychans are a kind of symbiotic relationship that I feel closely resembles that of the sea dragon with its symb. Yes, I'm actually comparing this sad tiny plant looking thing to a giant aquatic fireb breathing alien dragon. A lyken is actually two organisms working together and have existed before terrestrial plants.

[00:09:37]actually making land a place safe for plants to live in the first place. It's a species of algae and a fungus working together with the algae photosynthesizing and creating sugars for the fungus. The fungus provides the nutrients for the algae to make sugar, breaking down the rock they live on into its base components that it then gives the algae. Over millions of years, this created soil on Earth that land plants were able to survive in. In Subnotica, the sea dragon is the fungus, eating rocks and breaking them down into smaller bits that their symbiotic partner can work with. The partner in question takes the role of the algae.

[00:10:19]But instead of photosynthesizing to break down the rock, it relies on an analogous process called chemosynthesis using heat in place of sunlight. Certain microbial organisms do this around hydrothermal vents where they intake the minerals released from the earth and utilize them with the heat coming from the boiling water around them. Don't get me wrong, the sea dragon is still most definitely a carnivore, but it can still get some sustenance from rocks. The same goes for all the other creatures in the lava zone with the symbiote acting sort of like the base of the lava zone's food chain in lie of any plants.

[00:11:04]The sea emperor despite being very close to the dragon from an evolutionary standpoint could not be more different in terms of its ecological niche. While the sea dragons live deep within active volcanoes, spitting molten rock at prey items to hunt them down, the sea emperor's natural environment is far out in the void. Only coming to the crater or well-developed seamounts around 4546b to lay its eggs. The reason I specify the seamounts need to be welldeveloped is that in game, in order to craft the hatching enzymes for the sea emperor's eggs, we need samples from several different fauna species around the crater, indicating that the emperors favor thriving ecosystems for their young. However, when not reproducing, they spend their centuries or even millennia far out in the open water, hundreds or thousands of miles from any semblance of land or even shallower water. Something I forgot to discuss in the Ghost Leviathans video. While upwelling is best known for occurring in coastal areas using the rising seafloor to bring up nutrient-rich water from the deep, upwelling can also occur in open waters. Around the equator on Earth, upwelling can occur even far offshore as the strong currents pushing the surface water to the west pull deeper, colder, nutrient-rich water from the surface, allowing for phytolankton production.

[00:12:34]The same process occurs in 4546b's oceans. And so the sea emperors are able to spend hundreds of years growing in the void where they have no worries of predators, allowing them to take their time reaching sexual maturity. I will note that their mouth is not very well made for being a plank, but I also said that they can take centuries to mature. The other thing about the sea emperor we need to discuss is enzyme 42. The answer to the ultimate question or in our case the ultimate bacteria kura. It's important to note that the kora bacteria did not originate on 4546b meaning that prior to its arrival due to the precursors enzyme 42 would have seemingly no reason to exist. That is unless it had some other purpose. The only thing I can imagine it doing is killing some other bacteria species native to 4546B and somehow is also utilized by all the other species. Maybe this native bacteria got outco competed and driven to extinction when Kur showed up. I I don't know. The last thing we have to talk about is the emperor's telepathy.

[00:13:50]Come on. There's no way I can possibly equate this to something in real life or even something potentially real. There's no such thing as telepathy, at least in real life. Not among any living things.

[00:14:02]Even humans haven't created a way to talk to each other with just our minds.

[00:14:07]Maybe that Elon Musk Neuralink thing could do that one day, but the Sea Emperor does not have Neuralink, and neither do we yet. Also, it can speak to us in English for some reason. Anyway, doesn't matter. All that stuff is just convenient for the story.

[00:14:27]Thank you all so much for watching. I realize my hypothesis in this video are a little far-fetched even for me. If you've got a better idea, please let me know in the comments. Like what you see?

[00:14:39]A like and a sub go a long way. Anyway, that's all I got for you guys today. You all have yourselves a good one. And I hope you learned something.