28 STRUGGLE AMONGST ANIMALS 



in most parts of the world, the native black rats 

 everywhere giving way to the Norway rat. 



The truth is very different. There are two species 

 of rat in this country. The species corresponding 

 with the black rat of the popular story is known 

 scientifically as Mus raUus. It is rather smaller and 

 not so heavy as the Norway rat and can be dis- 

 tinguished superficially by its very large ears and 

 very long tail, the tail always exceeding the body in 

 length, and by certain characters of the teeth and 

 skull. The fur is smooth and soft. There are at 

 least two well-marked colour varieties, possibly dis- 

 tinct enough to rank as sub-species, one being very 

 dark and corresponding with the common designa- 

 tion " black " rat, the other, almost golden-brown in 

 hue, and known as the Alexandrine rat. Mus rattiis 

 is a better climber than the Norway rat and is the 

 typical barn and granary rat. The Norway rat, known 

 as Mus decumaniis, attains a greater size and weight, 

 is usually browner in colour with a harsher fur, and has 

 the ears relatively smaller and the tail shorter than 

 the length of the body. There is some confusion 

 resulting from the fact that melanistic or nearly black 

 varieties of the brown rat are quite common ; these 

 are often brought to the Zoological Gardens by 

 persons who believe that they have obtained exam- 

 ples of the old native rat. Mus decumanus is the 

 typical outdoor rat, the haunter of sewers and 

 drains. Although both rats are almost omnivorous, 

 the Norway rat is specially a scavenger, and the 

 black rat specially a feeder on grain. The black rat is 

 much more active ; in the East it nests in trees, in 

 the roofs of houses, in all sorts of inaccessible places. 



