of traditional clothing allowed fresh air to circulate through the outfit during physical exertion, removing air that was saturated with perspiration and keeping both the garments and the body dry. As well, animal skin is relatively porous and allows some moisture to evaporate. When temperatures are low enough for moisture in the air to freeze, it accumulates on the surface of fur as frost crystals that can be brushed or beaten away. Fur ruffs on hoods collect moisture from breath; when it freezes it can be brushed away with one hand. For footwear, animal skin provides greater condensation control than nonporous materials like rubber or plastic, as it allows moisture to escape, keeping the feet drier and warmer for longer. In comparison to skin and fur, woven fibres like wool absorb moisture and hold it against the body; in freezing temperatures, this causes discomfort, limited movement, and eventually, life-threatening heat loss. Waterproofing: Making garments waterproof was a major concern for Inuit, especially during the wetter weather of summer. The skin of marine mammals like seals sheds water naturally, but is lightweight and breathable, making it extremely useful for this kind of clothing. Before artificial waterproof materials became available, seal or walrus intestine was commonly used to make raincoats and other wet-weather gear. Skilful sewing using sinews allowed the creation of waterproof seams, particularly useful for footwear. Functional form: Garments were tailored to be practical and to allow the wearer to perform their work efficiently. As the Inuit traditionally divided labour by gender, clothes were tailored in distinct styles for men and women. A man's coat meant to be worn while hunting, for example, would have shoulders tailored with extra room to provide unrestricted movement, while also allowing the wearer to pull their arms into the garment and close to the body for warmth. The long back flap kept the hunter's back covered when crouched over and waiting for an animal. The was tailored to include a large back pouch for carrying infants. For both men and women's clothing, gores and slits allowed for parkas to be donned rapidly, and hoods were constructed to provide warmth while minimizing loss of peripheral vision. Durability: Inuit clothing needed to be extremely durable. Since the creation of skin clothing was a labour-intensive, highly customized process, with base materials available only seasonally depending on the source animal, badly damaged garments were not easy to replace.