4 



Rats and Mice 



The species does not appear to have been known to the ancient 

 Greeks or Eomans, and although a Roman altar (dating from 

 100-150 A.D.) in Rheims Cathedral is stated to bear the figure of 

 a rat, there is no clear evidence of the presence of the species in 

 western Europe before the time of the Crusades. No doubt the 

 navies of the Crusaders w^ere largely instrumental in bringing 

 this animal to our shores. Where climatic conditions permitted, 

 as in Sicily and the Balearic Islands, the species resumed a 

 natural life in the open, and it has maintained its primitive wild 

 coloration. 



In cooler countries, or in those with a greater range of 

 temperature, the species was forced to spend a good deal of time 

 within doors; in such circumstances it has developed a darker 

 belly and harsher fur, producing by such means the race called 

 i?. ?•. alexandrinus . A parallel change may be studied among 

 some of the Indian races, notably among those of the Central Pro- 

 vinces and Kathiawar. 



In colder countries, like Britain or Germany, the species was 

 only able to survive with the aid of the shelter provided by man. 

 In such regions it has entirely lost its primitive bright coloration 

 and has assumed the dusky garb of i?. r. rattus. This last change 

 appears to have been brought about rapidly ; for although the rats 

 imported by the Crusaders cannot have been any darker than is 

 B. r. alexmidrinus, their descendants by 1530 at the latest, judging 

 from the descriptions given by Georgius Agricola and by Gesner, 

 had acquired the full black dress. 



Once firmly established in the dwellings and stores of Western 

 Europe, B. rattus multiplied to an amazing degree ; it became and 

 remained throughout the Middle Ages, to the beginning of the 

 eighteenth century, a frightful pest, destroying much property and 

 food; moreover, the terrible outbreaks of plague, by which the 

 populations of Europe were so frequently devastated, are un- 

 doubtedly to be ascribed to this animal and its parasites. 



The arrival in temperate Europe of the Brown B^Sit, B.7iorv eg ic us, 

 from the East, in the early eighteenth century, introduced a new 

 factor ; a much stronger, more formidable and fecund animal, by 

 nature used to and fitted for a hard life in a cool country, this 

 rapidly spread over Britain ; wherever it came in actual contact 

 with B. rattus it killed the latter out, and it speedily, within the 

 space of fifty years, reduced the range of the weaker species to a 

 series of isolated and ever dwindling colonies. In this country. 



