The first people to inhabit the Canadian Arctic were Paleoeskimos, who migrated 4500 km across the Bering land bridge from north eastern Asia to Alaska and then Canada 4,000 years ago. These early inhabitants were dependent upon migrating game like caribou and musk ox. They were followed by people of the Pre-Dorset and Dorset cultures, whose balanced hunting economy made use of small land animals, seal, fish, and birds. In nearby Alaska, the Thule culture developed techniques for hunting large marine animals like walrus and whales. As a result of improved access to food, populations grew rapidly, complex societies emerged and conflict between groups became more serious. During a minor ice age that covered the High Arctic islands from 1650 to 1840, the Thule broke into small nomadic groups and migrated as far east as Greenland, developing new technologies in response to their immediate environment and, to varying degrees, exploiting techniques borrowed from other non-Native groups with which they came in contact. In the 19th century, change occurred again with the arrival of Europeans in search of the Northwest Passage. The Inuit exchanged skills, knowledge, skins and tools for guns, ammunition, fabric clothing and household goods. Today, Inuit culture combines traditional and modern technologies and social structures to thrive in their arctic environment.