Massive seabird of warm tropical oceans and coastlines. Overall black with extremely long, deeply forked tail and angular wings. Male completely black with inflatable red pouch on throat (not seen away from breeding colonies) and bluish eyering. In good light, black coloration can show purplish sheen. Adult female has white chest and golden bar on shoulder. Young birds have white head and breast. Often soars for long periods and flies with slow wingbeats. Steals food from other seabirds. Surprisingly acrobatic during aerial chases despite its large size. Limited range overlap with Great Frigatebird (mainly offshore western Mexico and in the Galapagos); identification is complicated by age and sex variation. Adult males are extremely similar; females and immatures best identified by exact pattern of white on head and breast, bill color, and eyering color.