There is a very nice interview at eurogamer.net.
http://www.eurogamer.net/article.php?article_id=56012
http://www.eurogamer.net/article.php?article_id=56012
Eurogamer: Presumably for the game to be in any way believable you've had to come up with a pretty interactive game world - just how interactive, and how big for that matter, is the world of B.C.?
Joe Rider: The simulation is based on modelling a working ecosystem where each creature shares a need for food, water and safety. If a creature is running out of food (for example) then it will be forced to migrate to a new nest. What effect does this have on the player? If the player has a raptor nest within a close proximity to camp, it might be useful to him to try and get rid of them. There are a number of ways in doing this. He can run in 'all guns blazing' and attempt to kill all of the raptors all off (risking the lives of his cavemen), or go the safer route and poison the raptors food supply (although this will take longer) or wait until night time and sneak in the nest using the Hunters skill and steal the eggs. It will then take them longer to reproduce and make it easier for the player to kill off.
The great things about the ecosystem are; 1) its easy for the player to see what's going on in the land as we show ecosystem details on an 'easy to understand' map screen, 2) every time you play the game you will get a different experience. Whenever we demonstrate BC at any game shows (like E3) it's a bugger to demo! Sometimes you can see some really cool goings on with the ecosystem with creatures fighting against each other, species dieing off, while other times the land will be quiet with each species appearing to observe each other anticipating attack. It makes the game completely unpredictable!
Eurogamer: At the time, that demo showed us how you can teach your cavemen certain tactics (like rolling a boulder down a hill to attack birds) by doing it yourself until they repeat it. It sounds rather Black & White-ish - is that a fair comment?
Joe Rider: There are obviously elements of the game that have evolved as part of the experience that Lionhead has acquired from developing previous titles. BC has a much greater depth of simulation than Black & White for example, and concentrates on this over very complex learning behaviours.