The subject of our sketch, the Prong-horned antelope (Antilocapra americana), is not as large nor so strikingly horned as the other animals which have been mentioned. In fact, so different is its structure, having hollow, pronged horns which do not increase by continuous growth, as do those of the true antelopes, but are shed like those of the deer family, and having a somewhat different structure of feet and different texture of hair, that a family has been made for it known as Antilocapridae. The Prong-horn ranges throughout the western part of North America from the Missouri river to the Pacific ocean, and from the Saskatchewan river south to the Rio Grande. It is not confined to the plains, but has been found in the wild valleys of the Rocky mountains to a height of over eight thousand feet above sea level. The daily life of this interesting animal is thus described by Canfield, who made an exhaustive study of them and who also kept them in captivity: "From the first of September to the first of March one always sees them in larger groups composed of bucks, does and yearlings. Shortly afterward the does individually retire from these herds and give birth to their young. After a short interval they again unite with other suckling does and their little calves, possibly with a view to common defense against the wolf and coyotes. The adult bucks roam about singly or two together, leaving the mothers with their latest progeny to their fate, the young Prong-horns in the meantime gathering in groups of their own apart from the older animals. Apparently tired of the world and bored by society the old bucks wander about for one or two months, frequenting localities in which they are not ordinarily seen. Two or three months subsequently the adolescent bucks again join the old does and their calves, and finally the old bucks also put in an appearance, so that one can observe herds, numbering hundreds, or sometimes even thousands, after the first of September. A herd never leaves its native locality or roams over more than a few miles of range. In dry summer weather they seek water and go to drink regularly once a day or twice in three days; but if the grass is fresh and green, as is the case during the greater part of the year, the Prong-horns do not drink at all." The food of the antelope consists to a great extent of the short, succulent herbage of the prairie, of moss, and also, to a limited extent, of the young and tender branches of trees. Like many other ruminants, this animal is passionately fond of salt and they will remain about saline deposits for many hours, satisfying themselves by licking the salty ground. The antelope is the swiftest runner of any animal in North America, though perhaps less agile and speedy than some of its relatives in the old world. It has been said by competent observers that so swiftly do they run that it is absolutely impossible to distinguish their limbs.