THE FAMILY OF RATS AND MICE 



{MiiriJci') 



HIS is the largest of all families among the mammals. It numbers a wide 

 variety of individuals. They are generally very small rodents with lower 

 incisors compressed; no premolars; molars rooted or rootless; and tail generally 

 nearly naked and scaly. 



Dr. Coues described the members of this family as " a feeble folk, com- 

 paratively insignificant in size and strength, holding their own in legions 

 against a host of natural enemies, rapacious beasts and birds." 



Few of us have any idea of the large number of these little beasts. They 

 are found almost all over the world, far outranking other forms in number. 

 In North America nearly one-fourth of all our four-footed animals belong to 

 this mighty family. There is, in fact, no escaping them. They invade our 

 pantries, our barns, our fields, our plains, and our woodlands. There are special types adapted 

 to nearly every environment, as for example the Wharf and Sea-going Rats. 



The family is therefore of great economic importance to man ; and its members — some 

 of them at least — may be fittingly described as the greatest travelers among mammals. 

 Probably not a ship enters or leaves our ports that does not have among its unlisted passengers 

 some enterprising Rat or Mouse. Dr. Rae some years ago captured at York Factory, on 

 Hudson Bay, a sijccimen of the Common House Mouse which had been brought from Europe; 

 and the Brown Rat has been seen on liners between San Francisco and Honolulu. 



In size the numerous species comprising the family range from the Musk-rat to the pygmy 

 Harvest Mouse. Every country has its own particular species, and North America has many 

 that are native. The fecundity of Rats is astonishing. In the temperate parts of the 

 United States, Rats breed three to five times a year; the Meadow Mouse brings forth 

 four to six litters. That Rats are the disseminators of disease has been established beyond 

 question. Not only do they convey the bubonic plague, but they are known to spread 

 trichinosis among swine. As they move about in all sorts of filth, it is obvious that they 

 must be active agents in the propagation of the germs of many other diseases. The Brown 

 Rat, the Roof Rat, and the Black Rat are, however, all " introduced " Rats. The native 

 American Rats are of a totally different character. Rats like the Wood Rat are not only 

 clean in themselves, but their food is of an unobjectionable nature; and, as will be shown 

 later, their flesh is both wholesome and palatable. 



In habits Rats and Mice are for the most part nocturnal. Many species live in burrows 

 or tunnel-like runways on the surface of the ground among the grass roots and seldom venture 

 forth into the light. Other species like the Musk-rat are aquatic and have become excellent 

 swimmers. While this family is popularly known as Rats and Mice, the two names refer to 

 the same type of animal, the distinction being chiefly one of size. As the sizes approach 

 each other, there is some confusion of terms, which is further heightened by the use of such 

 terms as Lemming, Lemming Mouse, and Vole. However, by dividing the present numerous 

 ^family into fairly well-defined groups, we shall be aided in our study of this industrious and 

 ubiquitous rodent. 



