Fig 7. (continued from Fig 6) Emergence of deterministic chaos in the conservative head dynamics as amplitude of motion is increased.

A, B: for large amplitudes (ϵ = 2/3, ϵ = 1), the Poincare section contains a large chaotic sea (i), while the MLCE converges to a positive value (ii), power spectra become “noisy” (iii), and autocorrelations decay rapidly (iv). These results strongly suggest the existence of deterministic chaotic head dynamics for large amplitudes. MLCE, power spectra, and autocorrelations were computed for initial conditions shown by black dot in panel i. Parameters used to generate this figure are detailed in the main text, and reported in S3 Table.