Marine mammals such as seals, bearded seals, walruses and whales not only provided valuable food for the coastal populations, but also important raw materials for their clothing and tools. In addition, they served as a sought-after means of exchange with neighboring inland groups. This led to the development of symbiotic relationships between inland and coastal populations as a way of coping with extreme climatic conditions. Further inland, land animals were hunted. Fur trapping was particularly important in earlier times as a means of acquiring useful tools and materials from foreign traders.