Sewer Alligators - A Spec Evo Reimagining! 🐊

Added: 2026-05-12

[00:00:00]We have all heard the urban legends of baby crocodiles and gators being flushed down the toilet and living in the sewers. And if you haven't, now you have. Let's give it a speculative look.

[00:00:15]Hey everyone. The idea of a large animal living in urban environments is nothing new. But what if we took these gators and made them not accidental dwellers of the underworld, but fully adapted to such an environment? That's what we will be doing here. So please consider liking, hyping and subscribing so the algorithm won't flush us down the toilet. And now, without further ado, let's get started.

[00:00:44]Humans often don't love it when animals walk into their urbanized environments.

[00:00:48]And truth be told, animals aren't great fans of it either.

[00:00:53]With our cars and asphalt and lights everywhere, it can be hard for them to find something close enough to their natural habitat.

[00:01:01]But luckily enough, some do. Like today's research subject, the North American crocodilian called microgator troglodytes, more colloquially known as the sewer gators.

[00:01:12]The explanation for such a name will be touched on in a couple minutes, but I don't expect it to be exactly a twist.

[00:01:20]As the ancestors of this species migrated north, they adapted to their increasingly colder environment by developing sturdier legs that reduce the area of their body through which body heat can be lost. While their tails became adapted to increase fat accumulation that let them survive during the colder months.

[00:01:37]This is aided by their ability to enter torpor, a metabolically reduced state, as a response to extreme conditions, especially winter.

[00:01:46]In contrast with most animals, these alligators present an inverse of Bergmann's rule, which states that animal populations tended to present larger sizes in colder environments.

[00:01:58]Sewer gators are, instead, much smaller.

[00:02:01]Owing to the fact that, as they traveled north, they also became adapted to life in underground habitats, including underwater caves and tunnels.

[00:02:11]This is not a rarity in crocodilians, as other species, like the dwarf crocodiles, present a similar lifestyle.

[00:02:19]M. troglodytes, however, present a much more derived body plan that reflects greater specialization to this environment.

[00:02:27]They are much smaller than other crocodilians, an adaptation to the lower availability of both food and space in these tunnels. As a smaller body helps them move with greater ease and survive with less food.

[00:02:39]As a further adaptation to the cramped spaces they needed to traverse, their bodies have become slender and their spines much more flexible. And resulting from the low oxygen conditions found in such habitats, sewer gators have developed an enhanced ability to store glycogen in their bodies, thus helping them resist long-term oxygen deprivation.

[00:03:00]The eyesight of these gators is very reduced in comparison to their close relatives, a result of the lack of light in their habitat.

[00:03:07]The rest of their sensory organs are, in contrast, much more developed. And this can be specially noticed by the relatively large size of their snout.

[00:03:17]Crocodilians have a large amount of integumentary sensory organs that help them sense the water around them, and are particularly developed in this clade, as it allows them to better navigate their environment in the absence of light.

[00:03:30]In particular, they help the sewer gators locate their prey, a diversity of small animals that can be found in caves.

[00:03:38]This lifestyle, of course, meant that once human colonization and urbanization began, these animals found a perfect place to reside in this new environment, storm drains.

[00:03:49]Popular culture often states these animals dwell in sanitation sewers, hence their name. But this environment is, in fact, too toxic for most animals to survive.

[00:04:01]While the strong immune system of these gators would allow adults of this species to survive in these sewers, they certainly would not have a good time about it. And the eggs and hatchlings would not resist long in such a place.

[00:04:14]The abundance of prey items in storm drains, including rats, roaches and mosquito larvae, will certainly more than make up a sufficient food source for these animals, hence making this, overall, a much better place for sewer gators than sanitation sewers.

[00:04:31]That said, we are certainly not here to talk about the virtues of any particular kind of drain. So let us move on.

[00:04:38]Despite how well these reptiles do in their underground habitats, they are not secluded to the depths and will occasionally leave the drains or caves they inhabit in order to bask in the sun, or even supplement their diet with the occasional squirrel, quickly returning to the darkness should any sign of danger arise.

[00:04:58]That said, sometimes these animals have been known to search for the light in less desirable ways, with their small sizes and flexible bodies making them capable of even climbing up toilets on occasion.

[00:05:09]You might recognize this behavior as the origin of the urban legends about baby alligators being flushed down toilets and surviving in the drains.

[00:05:18]Tales of stark white gators are particularly striking and have gained a lot of notoriety. And while sewer gators do present decreased pigmentation compared to other crocodilians, these stories are not based on the average member of the species, but on leucistic individuals. The relative commonness resulting from the very same habitat that shaped the rest of their bodies.

[00:05:40]See, most animals have a coloration that evolved as an adaptation to their environment, either helping them hide from unwanted attention, the eyes of their prey, or helping them attract mates.

[00:05:52]In the dark tunnels the sewer gators inhabit, color is meaningless, as light is scarce and color vision is rather useless. And so individuals with abnormal colorations, which would be easy to see above ground, manage to do just as well as their dark-scaled brethren.

[00:06:10]This means leucistic individuals can survive and reproduce just as well as any other of their species, causing them to be much more prevalent among their populations compared to most species on the planet.

[00:06:26]And that's it for Speculative Biology's look into sewer gators. With a special thank you to Alec Voicy for commissioning this one and giving me the basic biology to work on it.

[00:06:36]So, as mentioned at the beginning, the idea of alligators living in the sewers is famous enough as it is. But it is also rather nonsensical once you give it a closer look.

[00:06:47]First of all, who the hell flushes a baby alligator?

[00:06:51]Even if you don't care about the safety of a living being, that's just asking to get your toilet clogged.

[00:06:57]And haunted. There's no way a baby alligator fits through the toilet tube.

[00:07:02]I'm aware that's not the technical term.

[00:07:06]And second, there's the simple idea that these crocs would not only survive the trip and the sewers, but do it well enough to become adults and go around being creepy.

[00:07:15]So of course, rather than take this at face value, the idea for this episode was, instead, to imagine the idea of crocs in the sewers as their own species adapted to this environment, taking into account all the possible adaptations and the divergent appearance that would allow such an organism to survive, as well as its origin, with underground caves being the closest environment to sewers.

[00:07:38]Its physical look was very fun to adapt as well, turning it into something recognizably crocodilian, but quite different from any species we know.

[00:07:48]I hope you guys had fun. And please let me know of any other urban legends that would be fun to adapt this way.

[00:07:55]As always, big thank yous to everyone who wanted to see this episode. I hope you all liked it.

[00:08:01]And also thank you to our researchers and research associates who support us through Patreon and YouTube memberships.

[00:08:07]And once again, to Alec for commissioning it.

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[00:08:36]Thank you all for watching, and see you next time on the Speculative Wildlife Research Center.