There are of course a ton of tutorials available online about AI of enemies in games. Generally these don't go any deeper than simple state behaviours where (usually enemy) NPCs either stand still or chase the player in a straight path.

I want to create AI for animals that wander about, eat some food, flee from the player, etc. And this has to look like natural behaviour.

I was thinking about creating different states for the AI in which they look for or run away from different 'targets' depending on their needs. That's not that difficult to implement. Where I start to have trouble is when I want their movement to look realistic, i.e. random but not too random. If we move about we don't move in a single direction which randomly changes every couple of seconds.

Do you have any experience with programming a wandering AI in this way? If so, do you have any advice for me?