Unity 3D is a game engine. While the engine can create basic models and is used for terrain creation and decoration, I don't know if it is used for detailed modelling? Entity/animal models and some objects will likely have had their meshes created, rigged, textured and animated using an external 3D modelling program and then imported into the engine. Last I saw was that
Maya was the program used during the development of 2.0.X-2.5.1. (
source)
Based on
this post Dave made in the Wolf 3.0 devblog, this is still true.
