They set up a dummy of the Black Rat. The specific origin of the black rat is uncertain due to its disappearance and reintroduction. The principal threat to all these species is predation by the introduced black rat. Immediate baiting produced a dead black rat, "Rattus rattus". Raccoons and black rat snakes also feed on wren eggs and nestlings. The black rat displays great flexibility in its foraging behaviour. "Noronhomys vespuccii" was a fairly large rodent, larger than the black rat ("Rattus rattus"). Despite its name, the black rat exhibits several colour forms. A two-headed black rat snake with separate throats and stomachs survived for 20 years. The black rat is prey to cats and owls in domestic settings. Black rat bone remains dating to the Norman period were discovered in Britain. The black rat is black to light brown in colour with a lighter underside. The black rat occurred in prehistoric Europe and in the Levant during postglacial periods. The black rat is between long (not including the tail) and weighs between .