The margin of river, lake and sea has always attracted the first settlements of man because it offered a ready food supply in its animal life and an easy highway for communication.  Moreover, a water front made a comparatively safe frontier for the small, isolated communities which constituted primitive societies.  The motive of protection, dominant in the savage when selecting sites for his villages, led him to place them on the pear-shaped peninsula formed by a river loop, or on an island in the stream or off the coast; or to sever his connection with the solid land, whence attack might come, and provide himself with a boundary waste of water by raising his hut on piles above the surface of lake, river or sheltered seacoast, within easy reach of the shore.  In this location the occupant of the pile dwelling has found all his needs answered—­fishing grounds beneath and about his hut, fields a few hundred feet away on shore, easily reached by his dug-out canoe, and a place of retreat from a land enemy, whether man or wild beast.

[Sidenote:  Ancient pile villages.]

Such pile dwellings, answering the primary need of protection, have had wide distribution, especially in the Tropics, and persist into our own times among retarded peoples living in small, isolated groups too weak for effective defence.  They were numerous in the lakes of Switzerland[580] and northern Italy down to the first century of our era, and existed later in slightly modified form in Ireland, Scotland, England and southern Wales.[581] In ancient Ireland they were constructed on artificial islands, raised in shallow spots of lakes or morasses by means of fascines weighted down with gravel and clay, and moored to the bottom by stakes driven through the mass.  Such groups of dwellings were called Crannogs; they existed in Ireland from the earliest historical period and continued in use down to the time of Queen Elizabeth.  In the turbulent twelfth century, the warring lords of the soil adopted them as places of refuge and residence.[582] Herodotus describes a pile village of the ancient Thracians in Lake Prasias near the Hellespont, built quite after the Swiss type, with trap doors in the floor for fishing or throwing out refuse.  Its inhabitants escaped conquest by the Persians under King Darius, and avoided the fate of their fellow tribesmen on land, who were subdued and removed as colonists to Asia.[583]

[Sidenote:  Present distribution.]

Among Europeans such pile villages belong to primitive stages of development, chiefly to the Stone, Bronze, and early Iron Ages.  They are widely distributed in modern times among retarded peoples, who in this way seek compensation for their social and economic weakness.  In South America, the small timid tribe of the native Warraus till quite recently built their dwellings on platforms over the water in the river network of the Orinoco delta and along the swamp coast as far as the Essequibo.  These pile villages,