PLEISTOCENE CLIMATE AND MAMMALIA. 
391 
We come now to the species found at present only in 
southern climates, the cave lion and the cave hysena. The 
first of these is identical with the lion of Africa and Asia, and 
lived in the mountainous districts of Macedonia at the time 
that Aristotle was writing his “ Natural History.” The second 
I am unable to distinguish from the spotted hysena now found 
only in South Africa. Both these animals were, on the whole, 
larger than their living representatives, a difference which 
probably was caused by the abundance of food which they 
obtained, the hunters in those early days not being sufficiently 
numerous to compete with the carnivores for their prey. 
The mammalia, composing the fifth and most important 
group, now confined to the colder regions of the north, or to 
high altitudes in the northern hemisphere, consists of the 
glutton, reindeer, musk sheep, pouched marmot, tailless hare, 
and the lemming. 
From this short analysis of the Pleistocene fauna, we can 
realise the peculiar mixture of extinct animals with those now 
vanished to different regions of the earth. We have now to 
examine the conditions under which they must have lived in 
Europe during the Pleistocene age. We will take that re- 
lating to the climate first. The hyaena and the lion, living 
only at the present day in hot regions, imply at first sight 
that the temperature under which they lived in Europe was 
comparatively high. But, on the other hand, the fact that the 
tiger of the Altai is specifically identical with that inhabiting 
the jungles of Bengal, shows that the testimony offered by the 
carnivores as to climate is not altogether trustworthy. In the 
case of the lion, the temperature of the mountains of Thrace 
was undoubtedly infinitely more severe than that of any region 
in which it now lives, and most probably approaches to that 
under which it occupied the forests of Gfermany, France, and 
Britain. The spotted hysena may very likely have been en- 
dowed with the same elasticity of constitution as the living tiger, 
which enabled it to live in far colder regions than that in which 
it is now found. We may therefore dismiss the evidence of 
both these animals as to climate, as being liable to lead into 
error. The presence, however, of the genus hippopotamus in 
the Pleistocene fauna cannot be accounted for except by the 
hypothesis that during the time it lived here the climate was 
temperate, or even warmer than it is now. All the species 
of hippopotamus now alive spend the greater part of their 
lives in the water, rather than on the land. It is there- 
fore extremely improbable that any ancient species, so little 
removed in form from the living, could have inhabited a 
country in which the rivers were frozen for a considerable 
portion of the year. Had the Pleistocene hippopotamus been 
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