Behavior for dating
Today, Norway rats have almost completely replaced black rats in Europe and America, where black rats are now rare or absent in much of their former range.In contrast, in tropical zones black rats have the edge and are more common than Norway rats there (Nowak 1991).Rat-catchers captured and housed wild rats in cages as well (Matthews 1898).During this time, naturally occuring albino, black, and hooded Norway rats may have preferentially captured or selected from litters of captive rats for their distinctive appearance (naturally occurring wild albino rats were first reported in Europe in 1553 by Conrad Gesner, and Castle (1947) reports the existence of wild non-agouti and hooded rats as well).Thanks to his parents' job transfer, high school freshman Kazunari Usa finally gets to enjoy living on his own.His mother makes him stay at Kawai Complex, a boarding house that provides meals for its residents.White rats of European origin were brought to America shortly after this and became the foundation stock of American laboratory rats (Castle 1947).The oldest strain of inbred rats dates from 1856, when the Jardin des Plantes reported a feeder colony of black hooded rats.
After it arose, the Rattus genus underwent two episodes of intense speciation, one about 2.7 million years ago, and another began about 1.2 million years ago and may still be ongoing (Verneau et al. rattus skeletal remains in the Mediterranean and Europe dating to antiquity indicates that the black rat actually arrived much earlier. rattus bones have been found in Corsica that date to a point between the fourth and second centuries BC (Mc Cormick 2003), in Pompeii, Italy that date to the second century BC, and in London, UK from the mid-third cenutry AD (Armitage et al. Norway rats originated on the plains of Asia, probably in what is now northern China and Mongolia, where wild rats still live in burrows today.