An ecosystem that runs without the player, husbandry that is earned, hunting done entirely by hand.
The vision
Vanilla animals exist to be found. Here, they exist among themselves first: cross-species interactions, territories, breeding, hunting, and population regulation that happens on its own. The player is just one more predator in the picture.
An abandoned carcass draws scavengers, which makes the food chain visible and closes the loop: what dies feeds, then returns to the soil.
Each species holds the place that suits it: the wolf keeps a territory in mountains and forests, sheep move in flocks across the plains. A migration map tied to Season and Weather shifts those populations through the year, rather than freezing them where they were born.
An overhunted area empties temporarily, and refills only as fast as the population recovers. Game becomes a resource, not a dispenser.
Animals fear the player by default. No more cow following a stalk of wheat after two seconds: taming goes through the leash, or through regular presence until the animal grows used to you. A herd is built over time.
The animal remembers. A tamed beast recognizes its keeper, and a herd that has been overhunted grows warier and flees from further away. Behavior answers the player's history.
Across generations, traits pass down procedurally, size, temperament, coat. Selective breeding becomes a long-term goal, and a herd ends up resembling whoever raised it.
Killing a beast drops nothing on the ground. It must be skinned, the meat cut, the hide tanned, the bones recovered: each resource is a step, with its own gesture, not a loot line.
Before the kill comes the track. Animals leave signs, prints, hair, clues, that the hunter learns to read. To hunt is first to read the world.
Support for mod-added animals goes through family and behavior tags, with no list written species by species. Custom animals come in through the same door.