Rattus Norvegicus is the brown rat that displaced the earlier-prevalent and smaller European black rat. Although it's called Norvegicus, it originated in China, and I have no idea why it is called Norvegicus. Hmm, let me see... It came to Europe in mid-1500's. To the States in 1775. http://animaldiversity.ummz.umich.edu/accounts/rattus/r._norvegicus$narrative.html Apropos doors: the only film that scared me greatly when I was a kid was a film in which the plague begins and they board up the doors of a house where there were still living people, still healthy. Eeeew. My mother had to turn the TV off, I didn't want to watch anymore.

-- erlik