EUROPEAN AND AMERICAN BEAVERS 
as well. None has been known wild in England since historic 
records began; but their bones show that they must have been 
common enough there when the Roman pioneers landed, and 
they lingered in Scotland and Wales, according to Harting,’ 
until the twelfth century. On the continent they fared much 
better. A century ago they swam and worked in most of the 
larger German, French, and Austrian streams, and are not yet 
quite exterminated there, though the Swiss and Italian lakes, 
where they were so numerous in the days of the Neolithic lake 
dwellers, know them no more. It is less than a century since 
the animal abounded in Poland and western Russia, in the 
Caucasus, and even among the upper valleys of the Euphrates; 
but they are now scarce even in the remoter rivers of Siberia, 
whence formerly came bales of their skins. Everywhere, in 
fact, they may be said to exist only by the protection of some 
powerful landowner. 
Whether these European beavers, called Castor fiber, are really 
a different species from our Castor canadensis, is a matter of 
dispute, and of small importance; to all intents and purposes 
they are the same. 
This is only one of many examples of substantial identity in the animal 
life of North America and Eurasia. The brown bear, gray wolf, white 
and red foxes, sable, lynx, certain seals and cetacea, bison, wapiti, moose 
(elk), bighorn, beaver, lemming; many falcons, owls, sea birds and shore 
birds of many kinds, waxwings and several finches; and certain fishes, 
especially of the salmon family, — are prominent examples of cases in 
which convenience, rather scientific candor, causes separate species to 
be named. The reason of this identity, of course, is the nearness of the 
two continents to each other in the far north, and the fact that they have 
actually been connected since modern forms of animal life arose, so that 
the ancestors of these now separated races were presumably a continuous 
stock in the North, where we know a milder climate existed in the Tertiary 
period than at present. No department of natural history is more inter- 
esting or enlightening than that of the distribution of plants and animals 
on the face of the earth; and the relation of this distribution, past and 
present, to the habits and habitats of the several groups and species. 
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