CHAPTER XXXIXx 
THE MOUSE AND RAT FAMILY 
Mice are among the smallest quadrupeds known, there 
being no others to rival them in this respect, excepting the 
shrews. Rats are closely related to mice, being similar in 
structure and habits, and merely larger in size. We call 
those species rats that have a body and head five inches or 
more inlength. Allof the native i 
American rats, except the musk- 
rat, are much smaller than the 
common domestic rat. There 
are several hundred species of 
mice and rats in North America, 
all of them being native to the 
country except the house mouse 
and the domestic rat, — the two 
that are the best known and by 
far the most harmful of the 
whole family. We can present here only brief notes about 
those kinds that are commonest in the northern states. 
The House Mouse is the species that is commonly found in 
houses, barns, and stables. It also ranges along fences and 
over fields and takes possession of.grain shocks and stacks 
as soon as the harvest is over. It came to America from the 
Old World with the early colonists and follows civilized man 
in all his migrations, hiding away in packing boxes and freight 
cars and infesting the walls of wooden ships, and going whither- 
397 
Hovust Mouser 
