A gapeworm (Syngamus trachea), also known as a red worm and forked worm, is a parasitic nematode worm infecting the tracheas of certain birds. The resulting disease, known as "gape" or "the gapes", occurs when the worms clog and obstruct the airway. The worms are also known as "red worms" or "forked worms" due to their red color and the permanent procreative conjunction of males and females.