The Eastern Greylag Goose, Anser anser , was first domesticated in Egypt 4000 years ago and has given rise to eight varieties of farmyard goose. The Mallard, Anser platyrhynchos , was domesticated in China 2000 years ago and more than 10 varieties are now regularly farmed for meat and eggs. The Muscovy Duck, Carina moschata , was domesticated by the natives of South America long before the Spaniards arrived. The Swan Goose, Anser cygnoides , has also been farmed in some areas of Asia for some time. The down feathers that Eider Ducks pluck from their breasts to line their nests has, for centuries, been collected during and after incubation for use as an insulating material in bedding, hence 'eiderdowns'.
Most species are powerful flyers though there are several flightless species.
All except the Anhimidae which are a very distinct group, undergo a full simultaneous moult of the flight feathers and are thus flightless for a period every year. The three species of South American Anhimidae, commonly called Screamers, are included in the Anseriformes for anatomical reasons though they look more like strange chickens than ducks or geese. They are all relatively large birds with long strong legs and long toes. They are unique in living birds in lacking the uncinate processes which, in causing each rib to overlap its neighbour, greatly strengthens the ribcage. They also lack feather tracts, an unusually primitive condition shared with the Ratites, Penguins and African Mouse birds.