The English, Dutch, Swedes, French, and Spanish settled in North America at trading and exploring stations. So located, they could direct the flow of products to Europe. The English chiefly sought rare products such as gold and spices, and they sent back furs. The Dutch concentrated on furs. All European pioneers, however, had to feed themselves. This took a bit of doing, which at first involved a merging of European technology with Indian crops and methods. Later, the settlers adapted European crops and animals. In spite of starving times in almost every colony from Virginia to New England, the new Americans at least mastered the art of feeding themselves. European technology used animals for draft and employed plows, harrows, and similar implements. This technology fit European crops better than it fit American crops. Thus, European implements and draft animals did not appear until comparatively late. As long as they depended chiefly on Indian crops, Europeans simply substituted iron hoes for stone hoes, and iron axes for stone axes. But methods such as girdling, slash and burn, and the rest, came almost directly from Indian technology. The Pilgrims of Plymouth Plantation went 12 years without a plow; Virginians went almost as long. The hoe of corn culture served well enough to keep men alive. Hunting and fishing, of course, supplemented the food supply, as it did for the Indians. From north to south the story was largely the same in the 17th century. Everywhere the new Americans pursued a subsistence agriculture which supported some other major economic activity. Pennsylvania developed possibly the most flourishing subsistence farming. The commercial production of tobacco, an American crop with American methods and uses, began early in Virginia and Maryland. This specialty developed commercially almost exclusively in the upper South. Farmers and planters of the lower South had hesitantly begun rice culture, but as the 17th century ended men in the Carolinas still found hides and furs the most rewarding commodities. Meanwhile, rapid changes took place in the European metropolitan centers, and in the West Indian islands. The growth of population in both places created consumers for more and cheaper food. Markets for American foods definitely began to increase as the 18th century got under way.