FOUND UPON THE KARROOS. 93 
many parts of the desert. In unusually dry seasons, 
when the ordinary supply of vegetation fails on the 
karroos of the interior, innumerable flocks of these 
animals migrate southward in search of more abun- 
dant pastures, and thus new species are often 
encountered within the Colonial boundary which had 
never been seen south of the Orange River before, 
and which perhaps do not make their appearance in 
the same localities for many years afterwards. 
The migration of the spring-boks, or treck-bokken, 
which is of more frequent occurrence than in any other 
species of antelope, as I have had occasion already 
to notice, is much dreaded by the farmers of the 
Sneeuwhberg district, as from the countless multitudes 
of animals which unite upon these occasions to emi- 
grate in search of more abundant pastures, every green 
thing soon disappears from the surface of the earth, 
and the fields are left as bare and parched as if a 
cloud of locusts had rested on them. Hares, jerboas, 
and other different species of small rodent animals, 
are likewise found in great abundance upon these 
karroos; and of course where such variety of grami- 
nivorous and herbivorous animals are found, it is 
but natural to suppose that there will be no lack 
of carnivorous and ferocious beasts to prey upon 
them. We find accordingly that many different 
Species of such animals abound in Southern Africa. 
The lion, the leopard, and the cheetah, make their 
prey of the different kinds of antelopes, and sometimes 
