Naturalists divide swans into a number of different species. Whether this division is correct is not known. The habits of swans, and the circumstances under which they are usually kept, tend to prevent the mingling of different kinds. As far as the author has been able to learn, there is no evidence which shows conclusively the relations of any of the supposed different species. The differences between them are in some cases very slight. Some of the decisions of the naturalists who have classified slightly different kinds as distinct species are based upon examinations of very small numbers of specimens. Considering the apparent resemblances of the different kinds of swans in the light of what is known of species and varieties in fowls, ducks, geese, and pheasants, it seems probable that the true species of swans are fewer in number than the common classification shows, and it also seems quite possible that all swans are of the same species. =Description.= The common swan, called the domestic swan, is about the size of the largest domestic geese, but appears larger because it has a longer neck and head and larger wings. The body is also somewhat longer than that of a goose of about the same weight, and the swan is a much more graceful bird than a large goose. It is sometimes called the Mute Swan, to distinguish it from the Whistling Swan, which is a very similar kind not bred in domestication. There are other slight differences between the Mute Swans and the Whistling Swans, but the difference in the voice, if it really is as great as is supposed, is the only one of much consequence in deciding their relations. The Mute Swan is not dumb. It sometimes makes a low, whistling sound. People are not agreed as to whether there is any real foundation for the familiar tradition that the Mute Swan remains silent until about to die, and then sings a "song." Some people acquainted with the habits of swans declare that the swan is more vocal when dying than at any other time in its life. Others say that the idea probably arose as a result of some one's hearing a dying swan moaning in pain, as sick animals and birds often do, and concluding that it was uttering a series of sounds characteristic of swans in a dying condition. However that may be, the Mute Swan is distinctly less noisy than the wild Whistling Swan.