The term kayak means "hunter's boat." For the past 4000 years, they have traditionally been used in Inuit cultures to hunt animals on inland waters and the open sea, as well as for transportation across open water. Originally, kayaks were made from driftwood and seal skin. After forming the frame from the wood, the skin would be stretched out and sewn onto the completed frame. Any hair was removed, and the skins were made waterproof using oil. Today, modern kayaks are made from a variety of materials. Wood was most common until the 1950s, when fiberglass became available. Beginning in the early 1980s, kayaks have also been made of plastic.