The great frigatebird is a lightly built, large seabird up to 105 cm long with predominantly black plumage. The species exhibits sexual dimorphism; the female is larger than the adult male and has a white throat and breast, and the male's scapular feathers have a purple-green sheen. In the breeding season, the male is able to distend its striking red gular sac. The species feeds on fish taken in flight from the ocean's surface (mostly flying fish), and indulges in kleptoparasitism less frequently than other frigatebirds. They feed in pelagic waters within 80 km (50 mi) of their breeding colony or roosting areas.