No, feces are not classified as non-Newtonian fluids. Non-Newtonian fluids are substances that do not follow Newton's law of viscosity, which states that the shear stress of a fluid is directly proportional to the rate of shear strain. In non-Newtonian fluids, the relationship between shear stress and shear strain is more complex and can vary depending on factors like the applied force or the rate of deformation.
Feces, on the other hand, are generally considered to be pseudoplastic fluids. Pseudoplastic fluids, also known as shear-thinning fluids, are substances that become less viscous under shear stress. When feces are subjected to forces such as squeezing or stirring, they exhibit a decrease in viscosity, allowing them to flow more easily. However, when the shear stress is removed, they regain their original viscosity.
It's important to note that the consistency and properties of feces can vary based on factors like diet, hydration, and health conditions, so there can be variations in the behavior of feces from person to person.