_The Variety of Food Was Constantly Increased_.--Undoubtedly, one of the chief causes of the wandering of primitive man over the earth, in the valleys, along stream, lake, and ocean, {86} over the plains and through the hills, was the quest for food to preserve life; and even after tribes became permanent residents in a certain territory, there was a constant shifting from one source of food supply to another throughout the seasons. However, after tribes became more settled, the increase of population encroached upon the native food supply, and man began to use his invention for the purpose of its increase. He learned how to plant seeds which were ordinarily believed to be sown by the gods, and to till the soil and raise fruits and vegetables for his own consumption. This was a period of accidental agriculture, or hoe culture, whereby the ground was tilled by women with hoes of stone, or bone, or wood. In the meantime, the increase of animal food became a necessity. Man learned how to snare and trap animals, to fish and to gather shell-fish, learning by degrees to use new foods as discovered as nature left them. Life become a veritable struggle for existence as the population increased and the lands upon which man dwelt yielded insufficient supply of food. The increased variety of food allowed man to adapt himself to the different climates. Thus in the colder climates animal food became desirable to enable him to resist more readily the rigors of climate. It was not necessary, it is supposed, to give him physical courage or intellectual development, for there appear to be evidences of tribes like the Maoris of New Zealand, who on the diet of fish and roots became a most powerful and sagacious people. But the change from a vegetable diet to a meat-and-fish diet in the early period brought forth renewed energy of body and mind, not only on account of the necessary physical exertion but on account of the invention of devices for the capture of fish and game. _The Food Supply Was Increased by Inventions_.--Probably the first meat food supply was in the form of shell-fish which could be gathered near the shores of lakes and streams. Probably small game was secured by the use of stones and sticks and by running the animal down until he was exhausted or until he hid in a place inaccessible to the pursuer. The {87} boomerang, as used by the Australians in killing game, may have been an early product of the people of Neolithic Europe. In the latter part of the Paleolithic Age, fish-hooks of bone were used, and probably snares invented for small game. The large game could not be secured without the use of the spear and the co-operation of a number of hunters. In all probability this occurred in the New Stone Age.