Right now the ai does not exist. They might feel smart but we are faking it all.
The lifestyle director will be able to monitor thousands of ai entities on the map at once (we only spawn like 10 in the current build and just teleport them around to make it feel alive). So imagine every creature as a little ghost with a tiny amount of data like skin, gender, species, and current task, and goal. The director will keep track of that no matter where the player is in the world.
So we will spawn like 20 deer girls at their nest and they will be hanging out, socializing, doing nest things like grooming or playing games. And then 3 of them will adventure out to go look for food or something. The ai director will give tasks to everyone on the island and manage them all.
Once the player comes into radius of them then they populate into a 3d model. But if you track them and go away, you'll be able to come back to that exact deer 3 days later and she will be doing her stuff still.