ret 
7 
76 MOSTLY MAMMALS 
the presence of grassy plains alternating with the forest. 
The same is probably indicated by the numerous species 
allied to the guanaco, which flourished at the same time, 
and some of which attained the dimensions of a camel, 
while the various kinds of deer may also have inhabited 
the same regions. The gigantic hoofed mammal known 
as the Zoxodon, which had ever-growing teeth like those 
of a rodent, was, however, probably an inhabitant of swamps 
and marshes, while the still more extraordinary Macrau- 
chenia, with its slender, camel-like neck and long, three- 
toed limbs, probably stalked over the plains, cropping here 
and there the foliage from some tree or copse. Rodents 
nearly related to existing South American types were 
likewise common, and there were also certain large carni- 
vores, such as a species of sabre-toothed tiger and a huge 
bear-like creature. With the exception of these carnivores, 
together with the guanacos, horses, deer, and mastodons, 
which are unknown in the older formations, and are there- 
fore probably late immigrants from the north, all the animals 
of the Pampean formation are peculiar to South America. 
A further distinctive feature of this fauna is the large bodily 
size attained by so many of its representatives, this being 
especially the case with the glyptodons, mylodons, megalo- 
theres, guanacos, mastodons, macrauchenias, and toxodons, 
all of which would come under the designation of giant 
animals. In this respect the Pampean fauna corresponds 
with that of the Pleistocene period of Europe, with which 
it also agrees approximately in age, seeing that there is 
evidence of the contemporaneous existence of man with 
several of the extinct mammals. 
In certain parts of the Pampean formation the remains 
of these animals occur in extraordinary profusion, and 
generally in a perfect state of preservation. At times they 
