Most papers that try to determine the efficacy of masks have serious problems. Franky, cloth masks don't do anything positive. Bacteria already being in youre mouth is irrelevant. Its the number of bacteria. In your body dangerous bacteria can be overwhelmed by our defenses, and the environment itself, in small numbers, but a warm most mask is a suitable breeding ground. A tiny amount of organisms can quickly be cultured into a very dangerous volume. Which is what happens. Medical staff dont wear them all day: unfortunately, in a lot of places they do, due to poor training and lack of resources. Indeed, staff in all areas are being forced to wear masks for prolonged periods, when they are only supposed to be worn for short periods to be effective. Most medical staff, including doctors, are poorly informed and just parrot what they are told and read in advertising brochures. And from those who keep themselves well informed, you get the bunch who know and follow along because thats the easiest thing to do. Im not aware of any lizards.