  There is a long tradition of studying chaotic trajectories in systems whose
integrability is broken by means of an external perturbation. Here we explore a
different route to chaos, in the dynamics of extended bodies, which arises due
to finite-size corrections to the otherwise integrable motion of a test
particle. We find that cyclic changes in the overall shape of the body may lead
to the onset of chaos. This is applied to the Duffing and Yukawa potentials.
For Kepler's potential, periodic deviations from spherical symmetry give rise
to chaotic regions around the unperturbed parabolic orbit.
