RATS 141 



Mus decumanus, the so-called brown rat, 

 undoubtedly comes from Central Asia; and 

 at the present time there is a rat in China 

 described under the name M. humiliatus, 

 which is so little distinguishable from the brown 

 rat that it is thought to be the parent form. 



The migration westward of the brown 

 rat certainly took place much later than that 

 of M. rattus. Its first appearance is 

 difficult to date. Undoubtedly large hordes 

 of them crossed the Volga in the year 1727, 

 and continued their journey towards Central 

 Europe, The following year, according to 

 Pennant, brown rats, appeared in England — 

 Jenyns says not till 1730 — and almost certainly 

 they came in ships, for on its journey overland 

 it only reached Paris about the year 1750. 

 Reaching England about the year of the 

 second George's accession, and but thirteen 

 years after the first of the House of Hanover 

 succeeded to the throne, it was called — probably 

 by the adherents of the Stuart cause — ^the 

 Hanoverian rat. It was also called the 

 Norwegian rat — possibly from the mistaken 

 idea that it reached these islands from that 

 country. It has now passed to the northern 

 half of the New World, where it is gradually 

 driving out many of its weaker brethren. Its 

 numbers are, however, kept within certain 

 limits by wolves, lynxes, racoons, coyotes, 



