THE BEAR OF SOUTH AMERICA 
351 
is confined to the Andes between Colombia and Chile, that is 
to say, altogether to western South America. This range sug¬ 
gests that the bears are not originally a South American family, 
otherwise we might expect their having a wider distribution. 
The only alternative is that they migrated from some other 
part of the world to the part of South America where they 
still maintain themselves. Hr. von Ihering * argued that the 
ancestors of the South American bear originally came from 
Asia, and that they wandered across on a Miocene land con¬ 
nection which united eastern Asia with Central America with¬ 
out touching North America. In that case they would be older 
than the North American bears which, according to Professor 
Osborn,t belong to the much later Pleistocene Eurasiatic inva¬ 
sion. As a matter of fact, the geological history of the bears in 
America has never received the careful attention it deserves. 
Bears, it is well known, are entirely absent from Africa south 
of the Sahara, that is to say, from what is known as the 
Ethiopian Region, and no fossil remains of any members of 
the family have ever been discovered there. Hence it is un¬ 
likely that Africa was the source of the Ursidae or that they 
invaded South America by means of a direct land bridge from 
that continent as suggested by Hr. Ameghino. ij; The absence 
of bears from the whole of eastern South America indicates, 
moreover, that bears have made their entry from the west. The 
bears of South and North America are not closely related. 
They appertain to different genera. A fossil bear (Arcto- 
therium vetustus), belonging to a genus closely related to or 
identical with Tremarctos, has been recorded by Hr. Ameghino 
from the Entrerios deposits of Argentina which are of Mio¬ 
cene age. It would appear on that account as if Hr. von 
Ihering’s suggestion that the South American bears were older 
than the North American ones, and had quite an independent 
Asiatic origin, was borne out by palaeontological evidence. 
Since Arctotherium also occurs fossil in some Pleistocene 
beds of North America it must have spread northward in 
recent times and subsequently have become extinct there. 
* Ihering, H. von, “ Geschichte der Siidamer. Raubtiere,” p. 179. 
t Osborn, H. F., “ Age of Mammals,” p. 438. 
1 Ameghino, FI., “ Tetraprothomo argentinus,” p. 230. 
