Please note this project is still in progress, so there will be periodic updates and revisions as it goes. Art for each of the species is also still in progress and art for each species will be gradually added. Please bare with me as the project grows each day! And if you have any questions, you can email me or join my Discord! The invite link is on the footer of every page!

What is the Cetacean Alternative?

The Cetacean Alternative serves as a fun thought experiment and comprehensive exploration and re-imagining of the marine world in an alternate reality where plesiosaurs survived the Cretaceous–Paleogene extinction event and had since thrived for 65 million years, although they are instead referred to as cetophians instead of plesiosaurs. This project delves into the evolutionary pathways and ecological niches filled by these pescanguids, a family in the order Cetophiae, which itself is a very diverse order including families and subfamilies that fill the roles of pinnipeds and various other ecological niches, which include dolos, tikos, and hemots. I feel it is also important to note that pescanguids are not the only modern plesiosaurs in this thought experiment. The order Cetophiae is a rich and diverse order and the family Pescanguidae is not the only family present. Visuals for these organisms will eventually be provided. 

Other Divergences in the Cetacean Alternative

A popular question I have been asked about regarding this project is how other marine organisms and other groups are if plesiosaurs survived. And while I can't go into detail regarding all the groups, I can certainly clarify which ones survived or how other aspects of the  natural world fit into this. These next few sections will highlight some other groups, cetophians or not, that exist in this alternate reality

Dobjaridae 

A cetophian family consisting of rotund, semi-aquatic, pinniped-like animals. Members range in size from 2–4 m (6–9 ft) to as much as 5.7 m (20 ft) in length. The name derives from the Old Danish word dolo and the Old Nordic word for bear. Many genera retain the elongated necks of their ancestors, though their lower jaws flare outward with splayed teeth. This is a diverse group that inhabits mostly colder regions, with a few lineages adapted to warmer tropical waters. While most are omnivorous and feed opportunistically, some species specialise on vegetation or shellfish.

Dobjarids were well known to northern peoples for millennia, frequently appearing in oral traditions as ‘water bears’ or ‘neck bears.’ European explorers first recorded them in the early 1600s, describing them as ‘sea-bears’ for their rotund bodies and lumbering gait on land. By the 18th century, naturalists began classifying them as a distinct branch of cetophians, though their mixture of long necks and pinniped-like bodies puzzled many early taxonomists. Industrial-era hunting in the 1700s and 1800s, largely for meat and blubber, reduced several populations. However, their resilience and generalist diets prevented the catastrophic collapses seen in other northern animals. Today, dobjarids remain among the most widely distributed cetophians, thriving across subarctic and temperate waters.

Skirottidae

A family representing the surviving remnants of whale ancestors known as thubas. The name thuba originates from the Old English þēof (“thief”), in reference to the opportunistic behaviour of some members of this group. The family name Skirottidae derives from the Old English scip (“boat”) and rætt (“rat”), describing their oddly shaped, boat-like snouts and their overall rodent-like appearance. Unlike most cetophian lineages, skirottids did not remain strictly aquatic; while many are semi-terrestrial and adapted for life in water, several have pushed further back onto land.

Skirottids were noted by early northern communities for their cunning and persistence, often appearing in folklore as tricksters or thieves. Sailors and fishers of the 17th century described them in their logs as “water-rats” or “ship-rats,” a name inspired by both their snouts and their habit of stealing fish from nets. By the 19th century, naturalists recognised them as a distinct branch of cetophians. Despite hunting pressure in the 1800s for their meat and hides, most populations proved resilient, their versatility in diet and behaviour allowing them to recover where other animals faltered.

Today, the most familiar member of the family is the hota, a common semi-aquatic predator that fills a role remarkably similar to otters. Hotas hunt fish and shellfish with notable dexterity, but unlike otters they are larger, more territorial, and frequently aggressive in defence of their foraging grounds.

Ammoteuthids

In our world, ammonites vanished at the end of the Cretaceous, but in this timeline they persisted alongside cetophians in the form of ammoteuthids or “shell squids.” They have been part of human natural history for as long as squids and cuttlefish, recognised by coastal peoples, sailors, and naturalists throughout recorded time. Much like their ancestors, ammoteuthids combine an external chambered shell with a muscular squid-like body.

Size spans a wide range. Rare giants can reach up to 30 m (98 ft) in length with shells over 1.7 m (5.5 ft) tall, but most species are much smaller, often fox- to deer-sized or below. Compared with true squids they are more heavily armoured, with many bearing ridged or serrated shells, stout barbs on the tentacle pads, and powerful durophagous beaks capable of inflicting severe bites. Shell chambers provide hydrostatic control, allowing precise hovering and slow, energy-saving cruising. Jet propulsion is used for bursts of speed, with the shell’s keel and fluting helping to stabilise movement. Deep-dwelling forms often show bioluminescent organs along the mantle margins, while smaller open-water species rely on rapid colour change and disruptive patterns where the shell does not obscure chromatophores. Ecologically, ammoteuthids fall into two broad groups:

Pelagiteuthids (“open shellsquids”)- 

Small to mid-sized forms, usually no larger than a pony, with some genera the size of geckoes. They favour the open pelagic zones of the ocean and often carry spines or spikes along their shells and tentacles.

Gigateuthids (“mega shellsquids”)-

Larger, heavily armoured forms that dominate colder and deeper waters. Their shells and limbs are often lined with spines, spikes, and barbs. These are the forms most often embroiled in clashes with neodracodon hemots, sometimes as prey and other times as dangerous opponents capable of inflicting serious wounds. The shells of adult gigateuthids frequently bear scars from these battles, as do the bodies of neodracodons.

Their presence in human culture is ancient. Maritime folklore across northern oceans describes many-armed “ship-draggers,” tales that grew into legends such as the kraken and the Teukid. Early naturalists produced woodcuts and cabinet specimens of shells and arm barbs, while working fishers knew them as routine competitors and occasional hazards when large individuals approached the catch.

Today ammoteuthids occupy a broad sweep of niches. Pelagiteuthids anchor food webs as abundant mid-trophic prey, while the largest gigateuthids sit near the top of deep and polar ecosystems, locked in an ongoing arms race with neodracodons and the largest marine dobjarids

 The Sharks of the Cetacean Alternative

Because the oceans of this reality harbour a far greater abundance of megafauna than our own, other predators and competitors have diversified to meet the challenge. Sharks are among the most successful groups and it's here they show an ecological variety far beyond what is seen in our timeline. Some reach sizes comparable to the largest pescanguids, while others specialise in narrow feeding niches within reefs, kelp forests, or coastal estuaries.

The Tiko Shark (Carcharias tikoensis) is one of the most formidable, reaching 7–8 m (22–26 ft) in length. These sharks are adapted for hunting larger pescanguids such as the Williamson dolo, juvenile or weakened neptunes, and most famously the azure tiko from which they take their name. With massive jaws and a preference for targeting injuries or fatigue in their prey, Tiko Sharks remain a significant pressure on even the largest marine pescanguids.

Even larger is the Hemot Shark, which surpasses the size of a whale shark yet remains smaller than the leviathan hemots it shares the seas with. Whale sharks typically reach 12–14 m (40–46 ft), with the largest confirmed at 18.8 m (61 ft). The Hemot Shark exceeds this, averaging 20–22 m (65–72 ft) and occasionally larger, though it does not match the colossal sizes of the leviathan hemots. Like whale sharks, it is a filter-feeder, straining plankton and small nekton in vast volumes, and occupies a role as one of the largest planktonivores of the modern oceans.

Smaller sharks fill more precise niches. The Eel Shark is a slender, eel-like species around 1.3 m (4.3 ft) long that specialises in hunting reef-dwelling dolos. It hides within coral or rocky crevices, launching at high speed to bite at the necks of its prey. The accuracy of these attacks show just how long a coevolutionary relationship they have had with dolos if they are capable of striking exactly where the spinal column and major blood vessels are most vulnerable.

Another is the Pupsnatcher Shark, ranging from 2–2.5 m (6.5–8 ft). As its name suggests, it has become adept at preying on the pups of tikos, taking advantage of moments when parents are inattentive. With a combination of stealth and short bursts of speed, pupsnatchers either kill outright or seize the young before retreating into deeper water. This behaviour has driven strong defensive strategies in tikos, including tighter group vigilance and increasingly aggressive anti-predator displays from adults.

Smaller species such as the Zipper Shark (about 2 m or 6 ft in length) specialise in hunting newborn dolo pups, using speed and narrow jaws to exploit a life stage where dolos are most vulnerable.

The incredible diversity of sharks in this timeline also speaks to the broader differences in ocean ecology. Our own world’s seas are dominated by smaller-bodied fishes and relatively few species of giant animals, but here the abundance of aquatic megafauna creates a richer competitive landscape. Predator-prey dynamics occur at larger body scales, ecological niches are more finely partitioned, and the constant pressure from both sharks and pescanguids ensures that neither group dominates unchecked. This balance has thus brought forth a marine ecosystem of larger depth and variety. Plus a shark fighting a plesiosaur is cool as hell

Leptoceratopsids

By the end of the Cretaceous, a small leptoceratopsid now known as Manisceratops or "pangolin horned face" had managed to survive the end Cretaceous event. Much like Cetophians, this animal eventually diversified and gave rise to the familiar forms we know today as Pangolin Birds. Before the mid 1800s, pangolin birds were widespread all over northern Canada and found near larger bodies of water like estuaries, lakes, and rivers. But as more people became aware of them, they began to hunt them for their thick, heat retaining pangolin-like scales and their bright, colourful quills. In 1940, they were announced as critically endangered and their once great numbers had been reduced to a population of only 250 individuals and their range being reduced to only being found in Nova Scotia and the surrounding area. Their numbers have been gradually increased through a lack of hunting and conservation efforts, although they are still endangered. The name "pangolin bird" comes from the pangolin-like shingled scales covering their bodies that m,anage to retain heat in the colder regions in which they live while the "bird" in their name references the large parrot-like beak and natural avian alertness they possess. Their classification as "Ornithomanidae" literally translates to "Pangolin Bird". There are three surviving species in modern day. All three species are generalist omnivores that actively hunt dobjarid pups alongside shores, dig in the ground for roots, use their strong durophagous beaks for hunting shellfish and nuts, and generally browse and forage

Through detailed descriptions, taxonomic classifications, and notable depictions in media, the Cetacean Alternative gives a scenario on how these forms may look and react in a modern setting after taking the roles and niches that cetaceans rule in our own reality. This project has been a passionate project of mine for, at the time of writing this, nearly two years in the making. And while it was initially a minor writing assignment I did for fun in my free time, it has since evolved, much like the cetophians, into something deep and detailed with a potential to reach larger audiences. I hope readers of this project can be inspired by it, intrigued by it, or at the very least have something to read while they need to kill time! If you are coming for visuals, I apologise in advance, because it mostly reading based as of right now. Gradually, more art will be shared and provided to present a properly visualised project.

Inspirations

For as long as I can remember, I have been fascinated with the genre of speculative fiction/speculative evolution with my earliest attempts at the concept were silly little bat wyverns that shall never be seen in the public eye. And when I first saw the documentary "Alien Planet" on the Discovery Channel, I realised other people had the same idea as I did. And after watching that, I delved even further into the world of Speculative Evolution. Seeing books such as the "After Man" trilogy by Dougal Dixon, "The Time Machine" and "War of the Worlds", both by the legendary H.G. Wells, the highly underrated "Quintaglio Ascension Trilogy" by author Robert J. Sawyer, the wonderful project "Serina: A Natural History of The World of Birds" by Dylan Bajda (also known as Sheather888 on Deviantart), the "Alien Biospheres" series on YouTube by the channel Artifexian, and "The Future Is Wild" released on Animal Planet, I was officially in love with the genre. WIth myself being a part of many speculative evolution projects amongst friends of mine on various Discord servers, I felt like I wanted to go further from the confines of Discord. So, after some conversing with friends of mine, I decided to dedicate my time to working on this project. Many people have asked me why I chose plesiosaurs specifically to base my project on, and my only answer could be "Why not?". Many aspects of the speculative evolution as a genre is defined by the mindset of "what if this was like this" or "imagine if this thing eventually became this". And I always enjoyed plesiosaurs and their relatives as a group, so I just stuck with them. And despite what some of my friends have pointed out, no it's not because of the Loch Ness monster, but I did include a reference to the animal as a species of dolo.