Jellyamp

This is really well put together! The only thing I would add onto it would be more consideration for how animals interact with each other. Specifically, the behavior of certain prey animals would be different depending on if they are encountering a player or another smaller prey animal that they are hunting (for those that do hunt other animals). This isn't a super necessary addition as it might not add a lot of gameplay value but I think it would add to the immersion of the world. It would also probably require new types of animals like small rodents to be introduced. Since these animals would likely be of very little value to the player, it might make sense to have them only spawn in around larger prey animals to allow for those animals to engage in hunting behaviors (which the player could then take advantage of). If the player isn't nearby, then spawning them in wouldn't make sense as their purpose from a gameplay perspective would only be for adding immersion and a unique complication to the player's hunt of the larger prey animals. This would also help cut down on the amount of extra computation that would need to happen for an entirely new set of animals in the game. Also, it would just be fun to have small cats that the player could "domesticate" and keep in and around their homes to occasionally catch small rodents (domesticating cats might not be the right term but the general idea is that having large food stores would also bring with it rodent populations which could be managed by the player accepting the presence of a cat in and around their homes).