The two rodent strains, Apodemus sylvaticus and Mus musculus domesticus, are related, but genetic similarity sometimes provides no more resemblance than body shape or dietary preferences: closer analysis reveals entirely different and difficult-to-quantity behaviors between these two murids. With brains of different sizes and weights, these two sub-species have specialized to survive in different habitats, and their behaviors reveal how this specialization has occurred. In this article, we review the response of Apodemus sylvaticus and Mus musculus to a two-dimensional T-maze, in which the main standard and predictably domesticated variable to measure would be the choice of the left arm with a mirror at the end or the right arm of the maze. With the wild Apodemus species, another variable suddenly appeared that needed to be measured: to survive, the wild rodent attempts to anticipate its captor's (researcher's) strategy in order to do the opposite and escape. A research experiment with new behavioral parameters to measure in a new 3D definition of the T-maze that would become a battle of brains in the middle of a natural hunt. The contrast between Apodemus (active gripping, climbing, escape attempts) and Mus musculus (passive falling) resulted to be striking and is fully described. These results point to how new rodent species and the new psychological era require new behavioral metrics, which could involve an implementation of techniques used in some branches of modern neuroscience: behavioral neuroscience, animal cognition, and comparative psychology.