nels are placed
on the neighbouring trees. To the first warning a low cry responds; on
the second, announcing a nearer danger, all the band fly away with
vociferations which need no longer be restrained. The common Crane
(_Grus cinerea_), still more far-seeing to avoid a possible future
danger, despatches scouts who are thus distinct from sentinels who
inform their fellows of present danger.[46]

[46] E. Poppig, _Fragmenta zoologica itineris Chilensis_,
1829-30.

When these birds have been disturbed in any spot, they never return
without great precautions. Before arriving, they stop; a few only go
circumspectly forward, examining everything, and coming back to make
their report. If this is not satisfactory the troop remains
suspicious, sending new messengers. When they are at last assured that
there is really nothing to fear, the rest follow.

Thus by the most varied methods animals endeavour to save their
threatened lives, and succeed to some extent in attaining safety.
Destruction and the chase on one side, conservation and flight on the
other: these are the two chief acts which occupy living beings. Many,
however, less threatened, succeed in perfecting their manner of life,
and employ their industry in less pressing occupations than eating
others or preventing others from eating them.

CHAPTER IV.

PROVISIONS AND DOMESTIC ANIMALS.

PROVISIONS LAID UP FOR A SHORT PERIOD--PROVISIONS LAID UP FOR
A LONG PERIOD--ANIMALS WHO CONSTRUCT BARNS--PHYSIOLOGICAL
RESERVES--STAGES BETWEEN PHYSIOLOGICAL RESERVES AND
PROVISIONS--ANIMALS WHO SUBMIT FOOD TO SPECIAL TREATMENT IN
ORDER TO FACILITATE TRANSPORT--CARE BESTOWED ON HARVESTED
PROVISIONS--AGRICULTURAL ANTS--GARDENING ANTS--DOMESTIC
ANIMALS OF ANTS--DEGREES OF CIVILISATION IN THE SAME SPECIES
OF ANTS--APHIS-PENS AND PADDOCKS--SLAVERY AMONG ANTS.

The industries of the chase which are derived immediately from the
most imperious of needs--that of assuring the existence of the
individual--never arrive at a very extraordinary degree of perfection;
or at all events, as they are indispensable to existence, we are not
surprised at their development. It is unquestionable that an industry
marks a higher degree of civilisation not only by its development, but
still more by its reference to the less necessary things of life; in
every species the importance of the place given to the superfluous is
a mark of superiority. The animal