The human-mediated movement of species across biogeographic boundaries—whether intentional or accidental—is dramatically reshaping the modern world. Conservation biologists are grappling with the present-day effects of these introductions, but humans have in fact been reshaping ecosystems and translocating species for millennia. Acknowledging the effects of human-mediated species introductions through time is important for understanding present-day biodiversity loss, ecosystem functioning, and management needs. Here, we present the first database of terrestrial vertebrate species introductions spanning the entire...