Marine mammals provide an important comparative perspective on brain evolution, sensory specialization and the neural basis of complex behaviour. However, their brains also present substantial practical and analytical challenges. Many species have large brains, unusual brain shapes, high degrees of cortical folding and tissue properties that differ from standard laboratory models. In addition, specimens are rare, often obtained opportunistically, and may vary in fixation quality, post-mortem condition and completeness.
  In this talk, I will discuss how magnetic resonance imaging can be used to study the brains of marine mammals, with a particular focus on cetaceans and pinnipeds. MRI allows non-destructive examination of valuable specimens and provides access to internal brain organization, ventricular morphology, major fibre systems and volumetric relationships.
It is especially useful for large or rare brains, where conventional histological processing of the entire specimen is difficult or impossible.
  I will present examples from post-mortem MRI studies of marine mammal brains and discuss the methodological decisions involved, including specimen handling, fixation, segmentation and anatomical interpretation.
  By combining MRI with classical neuroanatomical approaches, these studies can provide new insights into the organization of marine mammal brains and their adaptations to aquatic life. More broadly, they highlight the value of including non-traditional and large-brained species in neuroscience, not as direct models of humans, but as comparative systems that broaden our understanding of mammalian brain diversity and evolution.