Maclear's rat (Rattus macleari) was a large rat which lived on Christmas Island in the Indian Ocean. Abundant, unfamiliar with and seemingly unafraid of humans, large numbers of the creatures emerged and foraged in all directions at night. Making querulous squeaks, the rats entered the Challenger Expedition's tents and shelters, ran over sleepers, and upset everything in the search and fight for food. Maclear's rat may have been responsible for keeping the population of the Christmas Island red crab in check, as recent numbers of the crab are greater than in the past. It is thought that black rats inadvertently introduced by the expedition infected the Maclear's rats with a disease (possibly a trypanosome), which in turn may have contributed to the species decline. The last recorded sighti