Techniques in neuroscience, especially imaging, have advanced at a remarkable rate. With MRI, we can now image the brain at submillimeter resolution without even cutting into it, and specialized imaging sequences, like diffusion tensor imaging (DTI), allow for the digital reconstruction of white matter pathways in situ. With this information, one can then determine how different brain regions are connected to each other, providing a blueprint of the brain’s functional architecture. These techniques have become standard fare within the human neuroimaging field and have begun to reveal structural differences in a variety of CNS disorders.

Despite the advances in neuroimaging tools, they have not been widely applied to the brains of non-human animals. Apart from humans, non-human primates, rats and mice, almost no information exists about the connectivity of other species’ brains. For example, what is it in a tiger’s brain that makes it a tiger? Or in a bear’s brain that makes a bear? The relationship between brain and species is fundamental to understanding the evolution of the nervous system, and can illuminate sensory, motoric, and cognitive adaptations that help situate each species in its ecological niche. A leading theory suggests that as brains get bigger they become more modularized. With new imaging tools and advances in network science, we can now test these ideas.