Mechanical (viscoelastic) properties play a crucial role in living systems with changes therein resulting in loss of function and diseases. Most often these are associated with properties on relatively slow time scales, corresponding to the observed deformation-rate of constituent structures. The significance of mechanical properties on very short time scales is thereby often discarded as un-physiological or only interesting by way of proxy. I will present several examples where these can however reveal and explain fundamental biological processes, and discuss one approach – Brillouin Light Scattering Spectroscopy/Microscopy – that we can use to probe these.