What is the physical difference between black and norwegian rats?

I don't want to know that the black rat spread the plague or that one is domesticated or one is cuter. If I saw a black and a norwegian rat side by side, how would I know the difference (Don't say one is black and the other isn't because there are black colored norwegian rats)|||The black rat (Rattus rattus), also called the ship rat or roof rat, is smaller than the brown rat (Rattus norvegicus), also called the common rat or Norway rat. It has a longer tail in comparison to body size, a more sharply pointed snout, and larger ears. I know you didn't want any mention of cuteness, but personally I find the brown rat cuter (and yes, pet rats belong to this species).





By the way, the black rat didn't spread the plague - it was spread by fleas, which lived on humans, dogs, cats, etc. just as much as rats.





Here some images:





Black rat:


http://www.cdc.gov/rodents/images/RRattu鈥?/a>


http://www.interface1.net/r8/rattus/ratt鈥?/a>





Brown rat:


http://www.naturephoto-cz.eu/pic/andera/鈥?/a>


http://www.noblepest.com/images/brown-ra鈥?/a>|||The Norwegian rat is larger. A rough average weight for the black rat is around 200g. You can double that for a Norwegian rat.|||there isnt really much of a difference to me, but i think the norwegian rat has messier hair.