Balleen is a material found as fibrous plates hanging in rows from the roof of the mouth in baleen whales (cetaceans of the suborder Mysticeti) and often known as whalebone. Baleen plates are broad at the base (gumline) and taper into a fringe which forms a curtain or mat inside the whale's mouth. Their function is to strain huge volumes of ocean water to capture food: krill, other zooplankton, crustaceans, and small fish. Strong and flexible, baleen was used for many purposes before the advent of plastic and spring steel. Among the items made from whalebone were women's corsets, buggy whips, and umbrella ribs. Most baleen whale species remain severely depleted because of this commercial whaling.