Researchers in Hong Kong have studied the spread of COVID-19 in hamsters. They have found that "wearing surgical masks can significantly reduce the non-contact transmission [...] especially when masks were worn by infected individuals". The study looked at hamsters in cages and the effect of a surgical mask as a partition between them. "With no partition in between the cages, two-thirds of the healthy hamsters were infected a week later. In the following two experiments with masks in between, the infection rates were lowered to one-third and one-sixth respectively."