Whether there are sex differences in the kinematic organization of non-reproductive behaviors is rarely addressed. In this thesis, evidence is presented that male and female rats organize their posture and stepping differently during a food protection task, contact righting, skilled reaching, and vertical rearing. Neonatal gonadal steroid exposure can alter sex-typical patterns of movement organization. Whether these differences are due to sex differences in body morphology or central nervous system (CNS) was also addressed using gravid females and tfm males. The results reveal that sex differences in movement are CNS based. Furthermore, the expression and choice of sex-typical patterns of movement can be altered by CNS injury. Finally, evidence is presented that sex differences in movement organization are also present in marsupials and insects. The implications of these results for our understanding of the evolution of sex differences in CNS anatomy and behavior will be discussed. / xvi, 249 leaves : ill. ; 28 cm.