Two recent articles about zoos caught my attention. The first shows that zoos can be an unanticipated pathway for the introduction of non-native species. In an analysis of 63 zoos in Spain, researchers discovered that "75% of the zoos studied were found to be problematic, while 14% of the animal housing was evaluated as 'insecure' against the possibility of escape." And, “Of the 1,568 animal houses studied, 221 were insecure against the threat of the species housed in them escaping, 167 housed non-indigenous species (potentially dangerous to the environment), and of these 21 housed invasive species”. To solve the problem the researchers recommend "not allowing animals to walk freely within the zoo grounds, and ensuring there is a physical barrier marking the zoo boundaries, and preventing individuals from escaping through drains, sewers or any other channels." Further studies on other zoos are much-needed to prevent zoos from becoming unwelcome corridors for the introduction of non-indigenous species.