The great Aras or Macaws, the large and handsome parrots of the Andes, act with much prudence when circumstances make it advisable, and they know when they ought to be on their guard. When they are in the depths of the forest, their own domain, they gather fruits in the midst of a deafening noise; each one squalls and cries according to his own humour. But if they have resolved to pillage a field of maize, as experience has taught them that these joyous manifestations would then be unseasonable and would not fail to attract the furious proprietor, they consummate the robbery in perfect silence. Sentinels 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.