On the island, there's no moon. There's also no tide.
There is a moon but given that the entire setting is a testing facility, be warned of inconsistencies.
The moon is always full.
Fridge Brilliance
The Aberration DLC has no large flying creatures, the closest being the gliding Rock Drakes. However a creature with a large wingspan would barely be able to maneuver in the caverns so they likely died out long ago.
The baryonyx's tail spin attack will kill pretty much any fish in a close proximity to it. Given that the areas baryonyx lives in are also typically home to megapiranha which like to attack their prey by surrounding it, the baryonyx likely developed this ability to counter that.
How is the player character able to identify previously unknown creatures, some unknown even to the player or wholly new species, at first sight? The One Who Waits has been guiding you through your implant the whole time, and is heavily implied to be Helena Walker, who literally wrote the book on all of them.
The City in Extinction, if you look at it from above (or a region map on the wiki) it is shaped exactly like a giant Specimen Implant that is on your left arm, it is surrounded by several proto-arks. Perhaps this is how the remaining humans turned themselves into Digital Humans.
Many of the unique creatures on the Aberration ark are difficult to tame or downright untamable, it's implied from Helena's journal entries that the animals of the arks are deliberately designed to be domesticated (she compares the taming process to stray dogs being re-socialised) and since the aberration creatures are the result of mutations and accelerated evolution then these features would have been lost or altered.
A similar reason could also be behind the difficulty of taming Scorched Earth's Wyverns and Mantises, journal entries imply they were created for the purpose of destroying large settlements and keep people nomadic. They were never meant to be tamed so the methods of doing so are more difficult and roundabout.
The artistic liberties and Jurassic Park references in the dinosaurs' designs could well be the doing of their in-universe creators.
The giganotosaurus. Wild and untamed, even at level 1 it's a vicious beast capable of killing almost anything it comes across. Tamed and domesticated by the player, it's inferior to a rex in almost every category. Why? Because the largest, most unparalleled non-boss carnivore the game has to offer just got beaten and owned by a creature the size of something it'd otherwise pick out of its teeth. The giga is a big bully that got a well-deserved beating, found out it's not the top of the food chain any longer, and has sunken into depression at having its spirit broken.
While patching the glitches in Genesis, the Controller can interrupt HLN-A to remark that some glitches were made when he began altering the system. It's a subtle aversion of Instant Expert: computer programming can be tricky even to the people who have studied it for decades, and despite being a genius in other fields, Professor Rockwell has no experience with computers, let alone something on the scale of Genesis. However, because he is a genius in other fields, he has the right temperament and skills to learn quickly... and in the meantime, he can get survivors like you to patch his mistakes for him.
Carnotaurus is large enough to body-block bosses' ground pathing, but small enough that they won't prioritize it as a target when larger creatures are available. The typical singleplayer boss strategy is to use an army of an "attack" dino to deal damage, while riding a Yutyrannus at the rear to provide buffs with its Mighty Roar. Using Carno as the attack dino allows a player to effectively pin the boss behind a wall of attacking Carno while it tries to futilely attack the Yuty instead. The fridge brilliance is that wild Carno and Yuty form packs together, and you can briefly command wild Carno from a tame Yuty: the game is suggesting this combo to the player!
Fridge Horror
You're on an island full of extinct creatures, most of them very dangerous. Homo sapiens is among them. What happened to humanity?
Given that you can find notes left behind equally-confused people from various time periods, it's probably some sort of Alien Zoo. Which raises a further question: how long have you been asleep?
Sometimes, when you kill a large predator like a titanoboa, raptor, argentavis, or megalodon, you'll find berries, recipes, tools, and clothing in their inventory. Now, where do you suppose those large, predatory animals got those item? Those bits and piece of equipment could easily be all that's left of another survivor after they were eaten whole with all their gear.
Moschops has an egg larger than its hindquarters. Uh, ow?
The respawn mechanic is the In-Universe result of memories being transferred into cloned bodies. Considering it's been going on for so long that entirely new species have evolved, just how many deaths did everyone on the ARKs have to endure?
The logs of The One Who Waits say that they specifically enabled the respawn mechanic beginning with Diana Altarus and culminating in the player. Prior to that, deaths were permanent.
On Ragnarok there is a cave where you fight the Iceworm queen. Once you kill her you go into her nest to find one of the artifacts, amongst her eggs is a dying Giganotosaurus. If he's still alive in a chamber full of eggs, does this mean....?
Alternatively, he could just be their first meal, which still isn't very pleasant.
