Dynamic Movement

Unlike with the multicellular stage that takes place mostly under water were you can more or less just point your self in a direction and go (with whatever method of movement you have); the aware stage and the stages that follow take place mostly on land. Land that has uneven terrain, trees (or equivalent), smaller plants, rocky terrain, rivers, lakes, bogs, sand, ect. How exactly are creatures gonna navigate that? Moving across a flat plan is obvious; but what about climbing, or swimming, or digging? Even uneven terrain requires different animations, let alone climbing up and around objects. I imagine climbing would be like a more limited version of swimming in thick forested areas (jungles for example) but how are all the crazy looking creatures that would obviously be developed gonna look doing so? This is basically a question of animation and mechanics. I assume there would have to be some sort of procedural animation for movement of all sorts; but what of the actual mechanics climbing? Swimming could just be ported from the multicellular stage and digging would probably be similar, I suppose. Moving in sandy, muddy/swampy, and snowy areas would have to have different animations and effect how you move if realism is to be maintained.