from northern supply stores, including commercially prepared skins of traditionally used animals, non-traditional skins like cowhide or sheepskin, and even imitation fur. Regardless of the source animal, Inuit traditionally used as much of the carcass as possible. Every portion of the hide had a specific use depending on its characteristics. Tendons and other membranes were used to make tough, durable fibres, called sinew thread or , for sewing clothing together. Feathers were used for decoration. Rigid parts like bones, beaks, teeth, claws, and antlers were carved into tools or decorative items. The soft material shed from antlers, known as velvet, was used for tying back hair. Intestine from seals and walruses was used to make waterproof jackets for inclement weather. The Russian word is sometimes used to describe all garments made from gut, although it originally only referred to gut robes made by the Aleut people of the Aleutian Islands. Due to the value of skins, old or worn-out skin clothing was historically not discarded at the end of the season. Instead, it was repurposed as bedding or work clothing, or taken apart and used to repair newer garments. In times of extreme need, such as when the caribou hunt failed, scraps of old garments could be re-sewn together into whole new garments, although these were less durable and provided less insulation. Through socialization and trade, Inuit groups throughout their history disseminated clothing designs, materials, and styles between themselves. There is evidence indicating that prehistoric and historic Inuit gathered in large trade fairs to exchange materials and finished goods; the trade network that supported these fairs extended across some of Arctic territory. They also encountered and incorporated concepts and materials from other indigenous Arctic peoples such as the Chukchi, Koryak, and Yupik peoples of Siberia and the Russian Far East, the Sámi people of Scandinavia, as well as non-Inuit North American indigenous groups. Caribou and seal The hide of the barren-ground caribou, an Arctic subspecies of caribou, was the most important source of material for clothing of all kinds, as it was readily available, versatile, and, when left with the fur intact, very warm. Caribou fur grows in two layers, which trap air, which is then warmed up by body heat. The skin itself is thin and supple, making it light and flexible. Caribou had to be hunted at specific times to ensure maximum quality of the skins. If taken