The black rat, roof rat, or ship rat (Rattus rattus L.) is among the most widespread invasive vertebrates on islands and continents, and it is nearly ubiquitous on Pacific islands from the equatorial tropics to approximately 55 degrees latitude north and south. It survives well in human-dominated environments, natural areas, and islands where humans are not present. Rattus rattus is typically the most common invasive rodent in insular forests. Few vertebrates are more problematic to island biota and human livelihoods than R.