In this paper we demonstrate distributed shape sensing based on stimulated Brillouin scattering in a multi-core fiber (MCF). Brillouin optical time-domain analysis with differential pulse-width pairs is implemented to measure the local tangential strain-induced variation of the Brillouin frequency shift along different cores of the fiber. Employing the differential strain measured in multiple off-center cores in the MCF, distributed profiles of both bending angle and fiber curvature are parametrically retrieved. The paper presents the first demonstration of distributed bending sensing, providing the cornerstone to further develop the system into a fully distributed 3D shape sensor.