Others, more democratic, instead of giving up the care of their safety to one individual, which cannot be done without abdicating some degree of individual independence, dispose around the place which they occupy a certain number of sentinels charged to watch over the common safety. This custom exists among prairie dogs, moufflons, crows, paroquets, and a great many other animals. The sentinels of the crows are not only always on the watch, but they are extremely discriminating; they do not give a warning at the wrong time. It is certain that these birds can distinguish a man armed with a gun from another who merely carries a stick, and they allow the second to approach much nearer than the first before giving the alarm.
Paroquets of all species live in joyous and noisy bands. After having passed the night on the same tree they disperse in the neighbourhood, not without having first posted watchers here and there, and they are very attentive to their cries and indications.
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]
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 animals who, foreseeing a hard season, or fearing the days when hunting will not be productive, lay up provisions to utilise in such times of famine, rise a degree higher than even the most skilful hunters. Not all amass with the same sagacity, and we shall find different examples of foresight, from the most rudimentary to the highest, very near what we may observe in Man.
The provisions harvested by animals have more than one destination: some are for the individual himself who has gathered them; others, on the contrary, are to serve as the food for his young at the age when they are not yet capable of seeking their own food. I will deal with these latter in another chapter, and propose at present only to speak of those animals who provision barns with the intention of themselves profiting by them.