Until 1697 all swans known to civilized people were white, and the swan was an emblem of purity of color. In that year a Dutch navigator visiting Australia found there a black swan. Afterwards a white swan with a black neck was discovered in South America. Had the subject of heredity been well understood before the discovery of these two swans that were not white, people familiar with the white swans would have known that there were colored swans in some unexplored country (or that they had existed in the known world in a former age), for white swans are not perfectly white at maturity, and when young they are gray. Neither is the black swan all black. It has white flight feathers, and its black color is a rusty black, that is, a black mixed with red. Swans are very long-lived birds, but stories of swans living to seventy or eighty years of age are not to be credited. It cannot be affirmed that the birds may not live as long as that, but the evidence in the cases reported is defective. The reports of swans living for fifty years are quite credible. The male and female swan are not readily distinguished, for there are no external indications of sex, and the birds use their voices so rarely that, even if there is a difference in the notes of the male and female, it is not practical to use it to distinguish between them. The only way to identify the sex with certainty is by observing the birds at nesting time. The name "swan" is Anglo-Saxon. Nothing is known of its derivation. The terms "cock" and "hen" are sometimes applied to swans as they are to many other kinds of birds. The swanherds in England call the male a _cob_ and the female a _pen_. The young swan is called a _cygnet_, from the French word for "swan." [Illustration: Fig. 176. Swan and nest] =Origin and history in domestication.= Tradition says that the domestic swan was brought to England from France by Richard the Lion-hearted. As the swan is a migratory bird, still sometimes seen in many parts of the Eastern Hemisphere north of the equator, it is possible that swans were known in England long before the reign of this king. However that may be, it is certain that, from about the time of the Norman Conquest, the swan has occupied a peculiar position in England. It was regarded as a royal bird, and the privilege of owning swans was granted only to those in high station. At first the number of those who were permitted to own swans was very small, but it was afterward extended until, in the reign of Queen Elizabeth, more than nine hundred different swanmarks were registered by the royal swanherd, who had general oversight of all the swans in the kingdom. The swans were marked by branding or cutting the bill, this being necessary because they lived largely on the margins of uninclosed waters, just as in some of our Western states cattle live on unfenced lands. The right to own swans carried with it the right to keep them in such a place.