CHAPTER IX. 
THE RODENTS, OR GNAWING ANIMALS. 
Photo by W. P. Dando] 
CAPYBARA 
This, the largest of the rodents, is found by the rivers of 
South America 
HE Rodents, or Gnawing Mammals, have all 
the same general type of teeth, from which 
the order receives its distinctive name. There 
are a very large number of families and of genera among 
the rodents, more than in any other order of mammals. 
All the rodents possess a pair of long chisel-shaped in- 
cisor teeth in each jaw. The ends of these teeth are 
worn into a sharp edge which cuts like a steel tool. In 
most rodents these are the only teeth in that part of the 
jaw, a wide gap intervening between them and the other 
teeth. The hares, rabbits, and calling-hares have a 
minute pair of teeth set just behind the large pair in 
the upper jaw. The grinding-teeth are set far back, 
and are never more than six in number, these being 
sometimes reduced to four. Rodents generally have 
five toes on the fore feet; in the hind feet there are in 
some cases only four, or even three. None of the 
species are of great size; the largest, the CAPYBARA, 2 
water-living animal of South America, is about the 
dimensions of a small pig. But the number of species 
of small rodents is prodigious, and their fecundity so 
great that they constantly increase in favourable seasons 
until they become a 
plague. Voles, lem- 
mings, field-mice, 
poe oy 
and rabbits are constant sources of loss to agriculture in their 
seasons of extraordinary increase. Most rodents feed on 
vegetables, though rats and mice have developed carniv- 
orous tastes. No rodents have canine teeth. 
THE SQUIRRELS. 
Those of the order of Gnawing Animals which have 
only two incisors in each jaw, and no rudimentary teeth like 
those possessed by the hares, are called « Simple-toothed 
Rodents.” Of these the family usually placed first in order 
is that of the SquirrEts and their allies. The True Squirrels 
and Marmots have five molar teeth on each side of the 
upper jaw. 
Squirrels are found in nearly every temperate part of 
the globe, from Norway to Japan, and in very great numbers 
in India and the tropics. Everywhere they are favourites ; 
130 
poe 4 off 
By permission of Professor Bumpus, New York 
FLYING-SQUIRREL 
One of the small species of the group 
