Swans are large waterfowl. The neck is equal to or longer than the body; The mouth shape is moderate, with a high base and a flat front end. The mouth nail is located in the middle of the mouth tip and does not occupy the entire mouth tip; Adult eyes are exposed first; Oval nostrils, located near the base of the mouth; The1The length of a primary feather is approximately2Half and Half of the Plum3The feathers are almost of equal length and are the longest among all feathers; Tail short and slightly round, tail feathers20～24The ankle is short and thick, located at the back of the body, and the anterior edge of the ankle is covered with reticular scales; Strong toes. The hind toe has a inguinal membrane. Same color for both sexes, or slightly lighter for females(Like a black swan)Most young birds are brown in color.