Remarkable water-stimulated shape memory effect was revealed in a natural biopolymer of peacock's tail
covert feathers of which the innate shape can almost be fully recovered after severe deformation by a
short hydration step. The shape memory effect manifests a good stability of high recovery rate and ratio
during cycles of deformation and subsequent recovery. Both strength and energy absorption efficiency of
medullary foam can be recovered despite the apparent decrease in the first deformation stroke caused by
structural damage. A kinetic model developed from non-equilibrium thermodynamic fluctuation theory
was adopted to describe the shape recovery process by considering the viscoelastic relaxation. The effects of hydration on mechanical properties, recovery kinetics, activation process and dynamic mechanical behaviors were also evaluated. Mechanisms were explored based on the lubrication, swelling
effect and structural changes of macromolecular chains or segments in terms of their mobility. This study
is expected to aid in understanding the responses of natural biological materials to environmental
stimuli and to provide useful information for synthetic shape memory materials from the bio-inspiration
perspective.