Bacterial biofilms are microscopic assemblages of bacterial cells usually attached to a surface and held together by a self-produced extracellular polymeric slime (EPS) matrix. Biofilms are ubiquitous in nature and are highly problematic in industry and medicine where they cause corrosion, fouling, contamination and chronic medical and dental infections. The EPS matrix is chemically complex and is composed of polysaccharides, lipids, proteins and DNA and protects the bacteria within from antibiotics chemical challenges and host immunity. There has been recent interest in how the bulk mechanical properties of biofilms may play a role in survival on surfaces against fluid shear forces by allowing the biofilm to respond to imposed mechanical loads over very short (ms) and very long (days to weeks) time scales. Creep and relaxation tests show that generally biofilms behave as viscoelastic liquids however and recent observations of high velocity impacts with water droplets suggest they rapidly form interfacial instabilities allowing them to flow over surfaces with velocities of meters per second. However, combining fluid shear with ultrasonically activated air bubbles was very effective at removing bacterial biofilms from textured glass surfaces. To determine the impact of different types and amounts of polysaccharides (PEL, psl and alginate) on the mechanical properties over the course of biofilm development we performed indentation and dynamic shear tests on mucoid, small colony variant and WT Pseudomonas aeruginosa colony biofilms. We hypothesise that variation in mechanical properties of sub-populations extends the 'insurance" hypothesis to the recalcitrance of the population to removal by physical forces. A better understanding of how bacterial biofilms respond and adapt to mechanical and antimicrobial stresses provides new opportunities to develop more effective removal strategies.