When a player gets within the range that a wolf will aggro, the AI first could check for other wolves in the area, and run a script telling the others about your location. The first wolf will follow you until the others catch up and help him take you down. Wolves generally hunt in packs so a simple script like this would add a lot of subtle nuance to their behavior.(I say simple, but I actually have no idea)
Stag, Chicken and Boar:(Prey 1)
If you simply reverse the wolf script, you can have a pretty simple ‘prey’ script. When there is no threat nearby, stags and boars could gather together(with other of their type) and stay near each other. When a threat comes within aggro range (such as humans, wolves, bears, etc) the animals will scatter in all directions, and it’s up to the hunter to decide which one they have the best odds of catching.
EDIT: One initial problem with making prey clump might be that they are harder to find, given that more will be killed per instance of one dying, since they are in groups. This could be offset by having more of these clusters, and just more animals in general. This way, you come across animals just as frequently as now(or desired) only in this way I’m describing you would find a group of 2-4 instead of just 1 by itself.
Bears don’t behave as socially as wolves or ‘prey’ animals that need to do that in order to survive. Most video of bears is of them eating food or lumbering around, which is pretty much what the AI is currently doing. Perhaps there’s an opportunity for some type of ‘hibernation’ script down the line, but as they stand I think bears are fine. (Except for their pathing might still be wonky, and they are a bit too slow right now IMO, bears in RL are REALLY fast)
Fish will require the most advanced script possible, since they are the smartest and most social creatures around. Just kidding. When fish someday exist in Rust universe, some type of script for making them swim in schools and scatter when threatened like the other animals would go a long way. This is for another day tho.
What animals would be a good next addition, and what unique behavior could you imagine for them? Vultures? Snakes? Drop Bears? Birds? Yes, all of the above please.