Many dispute the relevance of this, arguing that a brain-to-body mass ratio is more informative of intellect. Taking this into account, we would still lose; in this instance to the treeshrew because this humble creature has the greatest brain-to-body mass ratio of any species. So, in whichever way you pitch the battle of brain size, we still don’t reign victorious.
brain-to-body mass ratio, also known as the brain-to-body weight ratio, is the ratio of brain mass to body mass, which is hypothesized to be a rough estimate of the intelligence of an animal, although fairly inaccurate in many cases. A more complex measurement, encephalization quotient (EQ), takes into account allometric effects of widely divergent body sizes across several taxa. The raw brain-to-body mass ratio is however simpler to come by, and is still a useful tool for comparing encephalization within species or between fairly closely related species. *