Hat tip to Marginal Revolution, the Scientific American link is here. Money quote on how Elephants get their high cognitive capabilities without the sheer numbers of neocortical neurons that we have:
Benjamin Hart of the University of California Davis has speculated that the elephant cortex derives its intellectual prowess not from local density but from widespread interconnectivity. He suspects that, whereas the human and chimpanzee brains have evolved many tight-knit networks of nearby neurons throughout the cortex—akin to states packed with highly populous cities—the elephant brain has favored lengthy connections between far-flung brain areas, building the equivalent of an extensive cross-country railroad system. For now, though, this is mostly hypothetical.
This relates to some of my own work with my graduate student David Cooper, see here [pdf].