6 
ORIGIN OF LIFE IN AMERICA 
ten species now recognised in America will be reduced to 
four well-marked species. 
How long the caribou or reindeer has been in existence 
we do not know. Its remains have been discovered both in 
Europe and America in deposits believed to have been laid 
down during the Pleistocene Period, and as these occur far 
to the south of its present range, it has invariably been 
assumed that the species was compelled, owing to unfavour¬ 
able climatic changes to abandon its more northerly habitat. 
When the climate became once more suitable to its require¬ 
ments, the reindeer is supposed to have returned to its original 
home. This idea suggests that the reindeer originated in 
pre-Glacial times, and this view is, in my opinion, supported 
by the evidence of its occurrence, conjointly with the hyaena, 
in Irish cave deposits.* 
The whole subject of the influence of the Glacial Epoch 
on animals and plants will be dealt with later on, and need 
not be considered here. The fact of the occurrence of un¬ 
doubted reindeer remains far to the south of its present 
range certainly requires an explanation, and this is more 
easily given in conjunction with other facts to be stated 
in this chapter. While the reindeer still lives in Europe no 
(further south than the fifty-second degree of latitude, in 
America it is found no less than seven degrees further south. 
In former times it inhabited Oregon and Kentucky. In the 
east it came down to the neighbourhood of the present site 
of New York City, whereas in Europe it advanced as far as 
Mentone on the shores of the Mediterranean, and penetrated 
to the north of Spain, i.e., to the latitudes of the thirty-eighth 
degree in America and of the forty-third degree in Europe.f 
The musk ox (Ovibos moschatus) is another even more 
arctic mammal than the reindeer. So called from the musky 
odour of its flesh, this species was believed to be more closely 
allied to the sheep than to the ox, which it resembles more in 
size. In its geographical distribution it differs strikingly 
from that of the reindeer in so far as it is now quite confined 
to Greenland and arctic North America. It no longer inhabits 
* Scharff, B. F., “ Eui’opean Animals,” p. 112. 
t Brauer, A., “ Die arktische Subregion.” 
