Fast eBooks

But both alike are sufficiently
disproved by the interesting exceptions to the rule of white coloration
in the arctic regions, which exceptions are, nevertheless, quite in
harmony with the theory of protection.
Whenever we find arctic animals which, from whatever cause, do not
require protection by the white colour, then neither the cold nor the
snow-glare has any effect upon their coloration. The sable retains its
rich brown fur throughout the Siberian winter; but it frequents trees at
that season and not only feeds partially on fruits or seeds, but is able
to catch birds among the branches of the fir-trees, with the bark of
which its colour assimilates. Then we have that thoroughly arctic
animal, the musk-sheep, which is brown and conspicuous; but this animal
is gregarious, and its safety depends on its association in small herds.
It is, therefore, of more importance for it to be able to recognise its
kind at a distance than to be concealed from its enemies, against which
it can well protect itself so long as it keeps together in a compact
body.


Pages:
341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365