A study published in Science Advances found that vesper bats, the world's largest family of bats, carry two distinct copies of the genes involved in producing antibodies, whereas every other known mammal has only one such set. ^[1] Scientists from Tulane University discovered that bats possess two distinct systems of genes related to antibody production, whereas other known mammals have only one system. ^[2] Frank and her colleagues found that vesper bats have two separate heavy-chain gene systems, potentially giving them another way to create a wider variety of antibodies. ^[3] Hannah Frank, associate professor of ecology and evolutionary biology at Tulane University School of Science and Engineering, stated that this discovery completely changes the understanding of how mammalian immune systems can be organized. ^[4] Frank clarified that the discovery is an important piece of the puzzle but does not yet fully explain why bats are such effective viral reservoirs without getting severely ill. ^[5] The research focused on vesper bats, a group comprising more than 500 species, and the findings were published in the journal Science Advances. ^[6] The discovery was made in vesper bats, a group that includes more than 500 species living on every continent except Antarctica. ^[7]