The Cormorants (Phalacrocoracidae) is represented by 41 species of cormorants and shags. The name "cormorant" is a contraction derived from Latin corvus marinus, "sea raven".

The majority, including nearly all Northern Hemisphere species, have mainly dark plumage, but some Southern Hemisphere species are black and white, and a few are quite colourful. Many species have areas of coloured skin on the face which can be bright blue, orange, red or yellow. The bill is long, thin, and sharply hooked. Their feet have webbing between all four toes, as in their relatives.

All are fish-eaters, dining on small eels, fish, and even water snakes. They dive from the surface, though many species make a characteristic half-jump as they dive, presumably to give themselves a more streamlined entry into the water. Under water they propel themselves with their feet. Some cormorant species have been found, using depth gauges, to dive to depths of as much as 45 metres.

After fishing, cormorants go ashore, and are frequently seen holding their wings out in the sun. All cormorants have preen gland secretions that are used ostensibly to keep the feathers waterproof.