Wool is a natural fiber, primarily serving as a textile fiber obtained from sheep and certain other mammals. It is a biological material that protects animals from environmental conditions. Unlike synthetic fibers, wool originates entirely from living organisms, shaping its unique properties. This natural origin distinguishes wool from manufactured alternatives, impacting its properties and uses.
The Origin of Wool
Wool fibers originate from follicles within the skin of wool-producing animals. Sheep are the most prominent source, providing the majority of the world’s wool supply. Other mammals also produce wool-like fibers, including goats (cashmere, mohair), alpacas, llamas, and angora rabbits. The growth of these fibers serves as a protective fleece, insulating the animals from both cold and heat.
Wool is obtained through shearing, a method that involves carefully removing the fleece. Shearing is typically performed annually, often in the spring, to prevent overheating and maintain animal health. This practice mimics a natural shedding process for animals that do not shed their coats on their own. The wool fiber is a hardened protein and does not contain sensory structures, making the shearing process generally painless for the animal.
Characteristics Derived from Nature
Wool’s properties stem from its natural, protein-based structure, predominantly keratin, the same protein found in human hair and nails. Each wool fiber features an outer layer of overlapping scales, called cuticle cells. Beneath this, the fiber’s interior, known as the cortex, creates its natural crimp or wave-like structure.
This natural crimp is fundamental to wool’s insulating capabilities, as it traps air within the fabric, reducing heat conduction and keeping the wearer warm. Wool is also hygroscopic, meaning it absorbs moisture vapor, capable of holding up to 30-35% of its weight in water without feeling damp. Its outer surface is water-repellent due to a waxy coating and the overlapping scales, while its inner core draws moisture vapor away from the skin, allowing it to evaporate. This moisture management contributes to its breathability and helps regulate body temperature across varying conditions.
The protein structure of wool provides elasticity and resilience. This allows wool fibers to stretch significantly (up to 30% elongation) and return to their original shape without permanent deformation. Wool also exhibits natural odor resistance. Its ability to absorb water vapor helps keep the skin drier, discouraging bacterial growth that causes unpleasant smells. The fiber’s structure binds odor molecules, leading to wool fabrics retaining less odor compared to cotton or polyester.