Kaikaifilu (named after "Kaykayfilu", which translates to "Kaykay [the] Snake", a serpent deity in Mapuche mythology that serves as the supreme ruler of the seas and all its inhabitants) is a genus of mosasaur that lived in the López de Bertodano Formation, Seymour Island, Antarctica, 66 million years ago, during the Maastrichtian stage of the Late Cretaceous Period.
Kaikaifilu is a 10-meter (33-foot) mosasaur known from fragments of a skull 1.2 meters (4 feet) long, with heterodont dentition
Kaikaifilu is known mainly from 30 isolated teeth and fragments of its skull (including the jawbone), which, based on the skull of the tylosaurine Taniwhasaurus, may have reached a length of 1.2 meters (4 feet), possessing heterodont dentition (differently-shaped teeth), a feature not seen in any other mosasaur except the contemporary Eremiasaurus of the Ouled Abdoun Basin in Morocco. Of its post-cranial remains, all that has been discovered so far is a partial left humerus. It has been determined that the fossils belonged to an adult individual.[5][6] According to the calculations of Dr. Gregory S. Paul, Kaikaifilu is estimated to reach a size of 10 meters (33 feet) and a mass of 3 metric tons (3.3 short tons).[2][3]
A young Tuarangisaurus attempts to distract a Kaikaifilu to divert its focus from its pregnant, vulnerable mother
It is unknown whether Kaikaifilu is a mosasaurine or a tylosaurine due to having features that contradict its classification as a tylosaurine.[1] Prehistoric Planet appears to depict Kaikaifilu as a tylosaurine due to being proportionally slimmer than Mosasaurus. Regardless, it is medium-sized by mosasaur standards, being only around two-thirds the size of its largest cousins, making similarly-sized animals like the 8-meter (26-foot) Tuarangisaurus more willing to face it in direct confrontation. However, following Mosasaurus and Moanasaurus (both of which are theorized to live in the same formation as Kaikaifilu based on isolated teeth), it is the third-largest mosasaur of the Southern Hemisphere, and thus one of the largest and most dangerous marine predators to ever live in the waters around Antarctica.
Most squamates are ectothermic, reliant on the environment to keep their body temperature stable (equivalent to the outdated concept of "cold-bloodedness"). By contrast, mosasaurs are likely endothermic, able to generate favorable body temperatures with their own internal bodily functions. With body temperatures similar to those of seabirds during their time (e.g. Hesperornis and Ichthyornis), mosasaurs were able to stay warmer than the surrounding waters, making them highly-active predators capable of short bursts of energy and speed, an advantage over ectothermic competitors and prey. This is one factor that led to them becoming the apex predators in seas and oceans all over the world during the Late Cretaceous, with their "warm-blooded" nature allowing them to conquer even cold, polar environments,[7] hence the presence of Kaikaifilu in the López de Bertodano Formation in Antarctica.
Prehistoric Planet depicts Kaikaifilu as being mostly black, while its underbelly, the edges of its flippers and tail fin, and five bands wrapping around the center of its tail are creamy white, countershading the predator like its relative Mosasaurus, allowing it to blend with light when viewed from below, and be camouflaged with the depths when seen from above. Dark coloration in mosasaurs is supported by a study in 2014, when microscopic analysis done on a Tylosaurus nepaeolicus revealed that its scales have high traces of eumelanin, giving it a dark coloration like that of a leatherback sea turtle. Aside from aiding in camouflage, dark skin coloration also aids in absorbing and retaining heat (which is important for "warm-blooded" animals like mosasaurs), as well as adding protection against ultraviolet radiation from the sun whenever the animal surfaces.[8]
The Tahora Formation of Zealandia, a region Kaikaifilu would have plausibly visited
“ Back in the shallow waters of Zealandia, large groups of Tuarangisaurs have come together. They propel themselves with all four fins, and travel almost effortlessly to find the fish shoals that gather here in summer. ”
Kaikaifilu lived 66 million years ago in the López de Bertodano Formation of Seymour Island, which showed that the waters surrounding Antarctica were warmer than they are in the modern day, though, at 4 - 12 degrees Celsius (39.2 - 54 degrees Fahrenheit), the area was still very much cold, hence, the seas of Antarctica would have still been plausibly covered in sheets of ice, just as depicted in the sixth segment of Oceans.[9] This sort of environment poses dangers similar to what several diving animals face today, as these sheets of ice may prevent air-breathing animals from reaching the surface to breathe in time. While there is no evidence of Kaikaifilu living in the warmer waters of the Tahora Formation, given the distance between it and Antarctica, its presence in the warmer seas covering the submerged continent of Zealandia is not entirely implausible, an idea supported by the fact that its slightly larger relative, the Prognathodon-sized Moanasaurus, was present in both the Tahora and López de Bertodano Formation (based off of isolated teeth).
Paleofauna[]
Kaikaifilu confronts a pod of Tuarangisaurus
In the López de Bertodano Formation, Kaikaifilu lived alongside elasmosaurs like Morturneria and Aristonectes (which, being one of the largest plesiosaurs ever discovered, matches the mosasaur in size while being more than 3 - 4 times its mass), as well as several ammonites like Diplomoceras. Isolated mosasaur teeth may possible indicate that Kaikaifilu lived alongside other, larger mosasaurs, like Moanasaurus (normally found in the Tahora Formation in New Zealand) and Mosasaurus, as well as several sharks, several bony fish like Enchodus (which resembles Xiphactinus, a larger, unrelated predatory fish of another order), and invertebrates, among them, Diplomoceras and seven other ammonites, the nautilus Eutrephoceras, the serpulid polychaete worm Rotularia (previously mistaken for a sea snail due to its gastropod-like shape), two species of the sea urchin Cyathocidaris, gastropods, and bivalves. While the area is mostly known for its marine fauna, the land above also holds the fossils of at least five bird species, the elasmarian ornithopod Morrosaurus, an indeterminate hadrosaur, and an indeterminate theropod only known from fragments.[10]
A juvenile Tuarangisaurus leads a Kaikaifilu right to its pod, ready to confront and drive off the mosasaur
“ A pregnant Tuarangisaurus is in distress, and her young calf can sense it, as she travels waters that are home to the ocean's deadliest predators. ”
― The official Apple TV+ episode synopsis for Coasts
As believed to be the case for mosasaurs, this marine reptile likely lead a solitary life. Like all predator, Kaikaifilu is shown targeting what appears to be the weakest and easiest of prey, like a pregnant Tuarangisaurus. Even so, predators are not irrationally persistent in their pursuit of prey, they would back off when the risk and degree of injury is greater than the possible rewards it could get from a hunt, hence, a group of the same plesiosaurs vigorously assaulting it could successfully drive it away. Though a dangerous hunter in its own right, Kaikaifilu is not as feared as its more famous relatives, hence, the pod of Tuarangisaurus were willing to fight it off, but not the significantly larger and more powerful Mosasaurus in Oceans.
The sixth and final segment of Coasts takes place in the shallow waters of Zealandia, where large pods of Tuarangisaurus have come together to find the shoals of fish that gather in that area during the summer.
A Tuarangisaurus calf baits a Kaikaifilu into chasing it rather than its pregnant mother
“ But one female is not swimming with her usual grace. She and her two year-old calf are lagging behind the rest of the group. She's moving rather laboriously, and that has not gone unnoticed. ”
One female, more sluggish than usual, lags behind the group, with only her two year-old calf to keep her company. Her laborious movement is noticed by a Kaikaifilu, which closes in on her, since she appears to be the easiest target to kill. She attempts to escape to deeper waters, while her calf charges at the mosasaur to harass and distract it.
Several Tuarangisaurus drive a Kaikaifilu away from a pregnant member of their pod
“ For the calf, trying to distract the mosasaur is a dangerous game. But it's buying time. The mother and calf are not entirely alone. These individuals may be related, and it's in all their interests to drive Kaikaifilu away. ”
Just when the calf got the mosasaur's full attention, enraging it enough to really commit to pursuing the juvenile plesiosaur, at least 4 - 5 of the members of the Tuarangisaurus pod circle back and assault the mosasaur, snapping at it and forcing it to leave. With the hunter gone, the sluggish Tuarangisaurus, which turns out to be pregnant, can finally give birth in peace.
Subject The speed and acceleration of mosasaurs, as well as the means which allow them to perform the feats that make them quick, formidable, and powerful ambush predators.
Subject The speed and acceleration of mosasaurs, as well as the means which allow them to perform the feats that make them quick, formidable, and powerful ambush predators.
Experts Dr. Michael Habib, Kiersten Formoso
Footage of Mosasaurus from Coasts and Oceans, along with a brief moment of Kaikaifilu, are shown in this Uncovered segment, which is dedicated to discussing how fast a mosasaur could be.
“ Mosasaurs were seagoing lizards. Think of a giant, swimming, whale-sized Komodo Dragon. Tapered snout, rough skin, four fins instead of normal limbs, and a long tail that would look a lot like a shark tail, but upside down. That's basically a mosasaur. ”
― Dr. Michael Habib, University of California
Presented as the main focus is the largest mosasaur, Mosasaurus hoffmannii. The secret to the success of this ambush hunter is that it can move with incredible speed while it was only stationary moments before. Today, this is demonstrated by crocodiles, which have muscles that can deliver short bursts of tremendous power. Dr. Michael Habib, one of the show's consultants, brings up how mosasaurs may have bent themselves in a C-shape, then, in one sudden movement, push off of the water on the side of their bodies. As seen in modern-day fish, this "C-start" technique allows them to accelerate from a standstill to full speed in an instant. The suggestion is that mosasaurs use this same technique on a much greater scale. Using a 42-foot, 12-ton mosasaur for reference, the Prehistoric Planet research team ran a unique test four times to finally figure out exactly how fast can Mosasaurus hoffmannii actually swim.
“ This mosasaur could probably clear 75% of its body length in one single second. That means if that mosasaur is 17 meters away from you, in one second, it will be 75% closer, and in the 2nd second, it would have surpassed you and probably eaten you along the way. ”
― Kiersten Formoso, University of Southern California
The force generated by a mosasaur traveling at full speed is compared to the impact of a full-sized semi-truck, which, along with the mosasaur's powerful bite force, can prove immediately fatal.
Kaikaifilu pursues a juvenile Tuarangisaurus, the young elasmosaur risking its life to lead the mosasaur far from its initial target
“ Mosasaurs could reach 30 miles an hour in as little as one second. This is what makes them arguably the ultimate marine predator of all time. ”
― David Attenborough, Prehistoric Planet: Uncovered - How Fast Was A Mosasaur?
Going off of these calculations, Kaikaifilu, being 10 meters (33 feet) long, can cover a distance of 7.5 meters (25 feet) in one second, or 27 kilometers (17 miles) per hour. While this is the same as the top speed of Tyrannosaurus rex,[11]Kaikaifilu can reach this speed in a single second and would have been able to maintain it for a comparatively longer time, while T. rex would likely tire out before even reaching its top speed. It is also possible that, given how it is only two-thirds the length and one-fifth the mass of Mosasaurus hoffmannii, Kaikaifilu may have been, in theory, faster than these calculations (which are meant for mosasaurs the size and weight of Mosasaurus) make it out to be. Conversely, it is also possible that the extra mass and the greater amount of muscles and generated power allow the larger mosasaurs to accelerate with such great speed, and, due to being smaller and thus, lighter and packing lesser or proportionately weaker muscles, Kaikaifilu may not have accelerated to such great speeds, meaning that the calculation only works for mosasaurs possessing a similar length and mass as Mosasaurus.
↑Olivero, E.B.; Ponce, J.J.; Marsicano, C.A.; Martinioni, D.R. (2007). "Depositional settings of the basal Lopez de Bertodano Formation, Maastrichtian, Antarctica". Revista de la Asociación Geológica Argentina. 62 (4): 521–529.
