A pelican, derived from the Greek word πελεκυς pelekys (meaning “axe” and applied to birds that cut wood with their bills or beaks) is a large water bird with a large throat pouch, belonging to the bird family Pelecanidae.

Along with the darters, cormorants, gannets, boobies, frigatebirds, and tropicbirds, pelicans make up the order Pelecaniformes. Modern pelicans, of which there are eight species, are found on all continents except Antarctica. They primarily inhabit warm regions, though breeding ranges reach 45° south (Australian Pelican, P. conspicillatus) and 60° North (American White Pelicans, P. erythrorhynchos, in western Canada). Birds of inland and coastal waters, they are absent from polar regions, the deep ocean, oceanic islands, and inland South America.

Pelicans are large birds with large pouched bills. The smallest is the Brown Pelican (P. occidentalis), small individuals of which can be as little as 2.75 kg (6 lb), 106 cm (42 in) long and can have a wingspan of as little as 1.83 m (6 ft). The largest is believed to be the Dalmatian Pelican (P. crispus), at up to 15 kg (33 lb), 183 cm (72 in) long, with a maximum wingspan of 3 meters (nearly 10 foot). The Australian Pelican has the longest bill of any bird.

Pelicans swim well with their short, strong legs and their feet with all four toes webbed (as in all birds placed in the order Pelecaniformes). The tail is short and square, with 20 to 24 feathers. The wings are long and have the unusually large number of 30 to 35 secondary flight feathers. A layer of special fibers deep in the breast muscles can hold the wings rigidly horizontal for gliding and soaring. Thus they can exploit thermals to commute over 150 km (100 miles) to feeding areas.

Pelicans rub the backs of their heads on their preen glands to pick up their oily secretion, which they transfer to their plumage to waterproof it.