A male swan is called a cob. Male swans do not incubate the pen's eggs, but they swim close by and protect the nest from any predators. A female swan is called a pen, and their young are called cygnets.
Male swans are generally larger and heavier than female swans, weighing between 21 to 38 pounds. However, it is not possible to tell a male swan from a female swan without internally examining the bird's vent area. Swans lay three to eight eggs on average, one being laid every other day until the clutch is complete. Swans eat aquatic vegetation in the wild, but they eat corn and other grains in captivity.