Leptoptilos is a genus of very large tropical storks, also known as the adjutant bird. The name means thin (lepto) feather (ptilos). Two species are resident breeders in southern Asia, and the marabou stork is found in Sub-Saharan Africa. These are huge birds, typically 110–150 cm tall with a 210–250 cm wingspan. The three species each have a black upper body and wings, and white belly and undertail. The head and neck are bare like those of a vulture. The huge bill is long and thick. Juveniles are a duller, browner version of the adult.