al, by colouring it with such tints as may best
serve to enable it to escape from its enemies or to entrap its prey.
Desert animals as a rule are desert-coloured. The lion is a typical
example of this, and must be almost invisible when crouched upon the
sand or among desert rocks and stones. Antelopes are all more or less
sandy-coloured. The camel is pre-eminently so. The Egyptian cat and the
Pampas cat are sandy or earth-coloured. The Australian kangaroos are of
the same tints, and the original colour of the wild horse is supposed
to have been a sandy or clay-colour.

The desert birds are still more remarkably protected by their
assimilative hues. The stone-chats, the larks, the quails, the
goatsuckers and the grouse, which abound in the North African and
Asiatic deserts, are all tinted and mottled so as to resemble with
wonderful accuracy the average colour and aspect of the soil in the
district they inhabit. The Rev. H. Tristram, in his account of the
ornithology of North Africa in the first volume of the "Ibis," says: "In
the desert, where neither trees, brushwood, nor even undulation of the
surface afford the slightest protection to its foes, a modification of
colour which shall be assimilated to that of the surrounding country is
absolutely necessary. Hence _without exception_ the upper plumage of
_every bird_, whether lark, chat, sylvain, or sand-grouse, and also the
fur of _all the smaller mammals_, and the skin of _all the snakes and
lizards_, is of one uniform isabelline or sand colour." After the
testimony of so able an observer it is unnecessary to adduce further
examples of the protective colours of desert animals.

Almost equally striking are the cases of arctic animals possessing the
white colour that best conceals them upon snowfields and icebergs. The
polar bear is the only bear that is white, and it lives constantly among
snow and ice. The arctic fox, the ermine and the alpine hare change to
white in winter only, because in summer white would be more conspicuous
than any other colour, and therefore a danger rather than a protection;
but the American polar hare, inhabiting regions of almost perpetual
snow, is white all the year round. Other animals inhabiting the same
northern regions do not, however, change colour. The sable is a good
example, for throughout the severity of a Siberian winter it retains its
rich brown fur. But its habits are such that it does not need the
protection of colour, for it i