68 RODENTS. 
although it has been suggested that they are derived directly from the Marsupials. 
The number of genera of Rodents is great, that in a work like the present 
it is only possible to notice some of the leading and more generally interesting 
types. 
The whole of the Rodents are almost entirely herbivorous in their habits; and 
they all of them obtain their food by gnawing. We have already noticed that 
while the majority are terrestrial and burrowing, some are arboreal, others aquatic, 
and a few endowed with the power of spurious flight; and it may be added that 
of the terrestrial forms the hares are among the fleetest runners of all mammals, 
while the jerboas and chinchillas are distinguished by their leaping powers. They 
are mostly harmless and inoffensive creatures, fleeing with the greatest terror and 
precipitancy from the smallest of foes; but a few, like the common rat, when 
driven to bay, will defend themselves desperately, and will then inflict comparatively 
severe bites with their powerful front-teeth. 
Many Rodents yield furs which are very largely used in commerce, 
although of less intrinsic value than those of many other mammals. 
The flesh of hares and rabbits is largely consumed in Europe, while that of other 
members of the order is also eaten in various parts of the world; but the strong 
odour which characterises many Rodents renders their flesh more or less un- 
palatable. 
Value. 
As a whole, Rodents are characterised by their dull and frequently 
uniform coloration, although there are many exceptions to this. 
Indeed, many of the squirrels from the warmer regions of the globe, as well as one 
of the species of marmot, are among the most brilliantly coloured of all animals. 
In the brighter-coloured forms it does not appear that any rule can be laid down 
as to the plan of coloration. Thus while in many of the squirrels the brilliant 
colours take the form of distinct patches, distributed over various parts of the body, 
in the palm-squirrels and ground-squirrels there are light longitudinal stripes on a 
dark ground, and in the pacas there are light-coloured spots. It appears, however, 
that no Rodent exhibits transverse bars of different colours on the body, and in 
none is the tail ornamented with alternate light and dark rings. 
The tail is very variable; being totally wanting in the guinea- 
pig, while in the jerboas it attains an enormous relative length. 
Coloration. 
Tail. 
THE AFRICAN FLYING SQUIRRELS. 
Family ANOMALURID. 
The true flying-squirrels are confined to Asia, Europe, and North America, 
but Africa possesses a group of somewhat similar animals, which differ so decidedly 
in structure that they are assigned to a distinct family. 
Before considering these animals in detail, a few words are necessary as to the 
leading characteristics common to all the Rodents treated of in the present chapter, 
which are collectively spoken of as the squirrel-like Rodents, or, technically, as the 
Sciuromorpha. Together with the mouse-like Rodents described in the following 
chapter, all these animals are characterised by the angular process of the lower 
