Nature lubricates effectively and exclusively with water-based lubricants, while machines tend to be lubricated with oil.  Why is this? Firstly, water alone is a poor lubricant, especially in the boundary regime, but in natural systems it works outstandingly well.  The reason for this lies in the exquisitely constructed, and renewable, aqueous lubricant additives employed by nature.  Most of these molecules are glycoproteins, which consist of a proteinaceous backbone and sugar-based side-chains.  The protein assists in the anchoring of the molecule on surfaces, the sugar chains forming water-saturated brushes that provide a lubricious interface.  In industrial applications, we are (currently) unable to design systems that are renewable, but we can imitate the architecture of natural systems and create self-anchoring, brush-based aqueous lubricant additives based on synthetic polymers. We have, over the last few years, synthesized many polymeric structures that spontaneously form brushes of either poly(ethylene glycol) or sugar chains on a wide variety of surfaces.  The lubricity of these systems rivals that of natural systems and, in contrast to covalently attached brush systems, the brushes reform on the surface following damage by wear processes. These systems have the potential to partially replace oil-based lubrication systems in a number of industrial and medical applications.