Moreover the people of the northwest coast had the advantage of not being forced to move from place to place in order to follow the fish. They lived on a drowned shore where bays, straits, and sounds are extraordinarily numerous. The great waves of the Pacific are shut out by the islands so that the waterways are almost always safe for canoes. Instead of moving their dwellings in order to follow the food supply, as the Eskimo and the people of the pine forest were forced to do, the Haidas and their neighbors were able without difficulty to bring their food home. At all seasons the canoes made it easy to transport large supplies of fish from places even a hundred miles away. Having settled dwellings, the Haidas could accumulate property and acquire that feeling of permanence which is one of the most important conditions for the development of civilization. Doubtless the Haidas were intellectually superior to many other tribes, but even if they had not been greatly superior, their surroundings would probably have made them stand relatively high in the scale of civilization. Southward from the Haidas, around Puget Sound and in Washington and Oregon, there was a gradual decline in civilization. The Chinook Indians of the lower Columbia, beyond the limits of the great northern archipelago, had large communal houses occupied by three or four families of twenty or more individuals. Their villages were thus fairly permanent, although there was much moving about in summer owing to the nature of the food supply, which consisted chiefly of salmon, with roots and berries indigenous to the region. The people were noted as traders not only among themselves but with surrounding tribes. They were extremely skillful in handling their canoes, which were well made, hollowed out of single logs, and often of great size. In disposition they are described as treacherous and deceitful, especially when their cupidity was aroused. Slaves were common and were usually obtained by barter from surrounding tribes, though occasionally by successful raids. These Indians of Oregon by no means rivaled the Haidas, for their food supply was less certain and they did not have the advantage of easy water communication, which did so much to raise the Haidas to a high level of development.