Neither rat species is native to North America, said Buckley, of the University of Manchester in the United Kingdom. Scientists used to think that brown rats arrived around 1776.

Neither rat species is native to North America, said Buckley, of the University of Manchester in the United Kingdom. Scientists used to think that brown rats arrived around 1776.

Brown rats were thought to have arrived in North America in the 1770s, but a new study suggests they may have sailed across as early as 1740. (Image credit: PauGrace Photography Somersham via ...

Neither rat species is native to North America, said Buckley, of the University of Manchester in the United Kingdom. Scientists used to think that brown rats arrived around 1776.