Colouring is either pure white or gray or black. Females and males outwardly very difficult to distinguish. Swans from the geese are distinguished by a longer neck, allowing deeper water to search the bottom looking for food, as well as their quantity, where they are the largest water birds. Sweep their wings up to two meters, and the weight can exceed 15 kg. Legs rather short, because of what the swans moving on the earth, made a clumsy impression. But they have very well-developed flying muscles, allowing them to travel thousands of miles when the annual flight to the South and back.