ABSTRACT
Rats are thought to have originated in the area of Asia currently occupied by Southern Russia and Northern China. Rattus rattus (black or ship rat, 2n = 38) was well established in Europe by AD 1100 and implicated in the bubonic plague that devastated most of Europe in the 1300s. Rattus norvegicus (brown rat, 2n = 42) was commonly found in Europe in the 1700s. This appearance followed thousands of years of absence. Fossilized rat remains dating to the Pliocene and Pleistocene epochs have been found in Europe. Until the writings of Giraldus Cambrensis (1147-1223), there was no distinction made between R. rattus and Mus spp. (mice). The late European arrival of R. norvegicus is offset by its ferocious nature, helping it to essentially eradicate the black rat from its former strongholds.
