The Great Kangaroo, or ‘boomer’, or ‘old man’ (Macropus giganteus), attains a height of about five feet when standing upright. The fore limbs are very short, the hind long, with powerful, elongated feet. The fore limbs bear five digits armed with strong claws; the hind have only four. The head is small, with pointed muzzle and large ears. In accordance with its purely vegetarian habits, canine teeth are absent in the adult. The incisors are powerful, with a cutting edge. The fur is soft and woolly, and lighter in tint below than above. In the female there is a large pouch, in which the young are placed at birth, and become attached by their immature months to the nipples. At this time they are minute -- not more than an inch in length -- and, being to immature to suck, have milk pumped into them by their mother. They remain withing the pouch until able to run by the side of the parent. Not until some eight or nine months after birth are they left to shift entirely for themselves. Only one young one is produced at a birth. As regards internal organs, the stomach is large and complex, and the characteristic marsupial or epipubic bones are present.
John H. Finley ed. Nelson's Perpetual Loose-Leaf Encyclopaedia (vol. 7) (New York, NY: Thomas Nelson and Sons, 1917) 61