Elastomeric proteins evolved in a diverse range of animals and often fulfil highly specialised biological functions as the elastin in the pulmonary alveoli of higher vertebrates, the resilin in the wing joints of insects or the spidroin in the threads of spider silk.
They give tissues mechanical properties that exceed those of artificial materials.
These proteins, known as elastomers, share a common property -- structurally disordered, repetitive protein sequences that store energy when a molecule is stretched which then can be used in the form of a movement after release. These movements can be rhythmical, as in the blood vessels leaving the heart.
Or they can be single, explosive movements, as in the jump of a grasshopper.