Which natural fiber material best maintains its insulative properties when wet?

Wool is considered the best natural fiber material for maintaining its insulative properties when wet due to its unique structure and properties. The fibers of wool have a natural crimp that creates air pockets, which serve as insulating barriers. When wool gets wet, it retains some of its insulating capabilities because it can absorb moisture without losing its thermal properties. This is due to the ability of wool fibers to hold moisture within their structure while still insulating the body from cold temperatures.

Additionally, wool can retain warmth even when it is damp, making it an excellent choice for conditions where one may be exposed to both moisture and cold. Its ability to wick moisture away from the skin and release it into the air also contributes to its overall effectiveness in insulation under wet conditions. This makes wool particularly valuable for outdoor activities and search and rescue operations where exposure to the elements is a concern.