Brain weight is not always directly related to body weight in cats: the roles of right and left cerebral hemispheres, paw preference and sex-related differences.

The relationship between weights of the cerebral hemispheres and body weight was studied in cats. The total weight of the right (R) and left (L) cerebral hemispheres was not significantly correlated with body weight in right-pawed (RH) male cats and left-pawed (LH) female cats. There was a significant positive linear correlation between R + L brain weight and body weight in RH female and LH male cats. The right-brain weight was directly correlated with body weight in RH female and LH male cats (no significant correlation between right-brain and body weight in RH males and LH (females). The left-brain weight was found to be directly related to body weight in RH males, RH females, and LH males, but inversely related to body weight in LH females. It was suggested that some hormonal factors influencing body growth may affect the development of the brain growth asymmetrically and differentially.