The largest animal of this tribe is the Huanacu or Guanaco. He measures five feet from the bottom of the hoof to the top of the head, and three feet three inches to the shoulders. So nearly does he resemble the llama in form that, until very recently, zoologists supposed the latter to be an improved species of the huanacu, and that the huanacu was neither more nor less than a wild llama. But there are specific differences between them. The huanacu is of a uniform reddish-brown colour on the neck, back, and thighs. The under part of the body, the middle line of the breast, and the inner side of the limbs are of a dingy white. The wool is shorter and coarser than that of the llama, and of nearly uniform length on all parts of the body. The huanacus assemble in small herds of five or seven, and if taken very young may be tamed, but can with difficulty be trained as beasts of burden. The Vicuña is a more beautiful animal than either of the preceding. His size is a medium between that of the llama and alpaca. He measures four feet one inch to the top of the head, and two feet six inches to the top of the shoulders. He is distinguished by his longer and shapelier neck, by the superior fineness of his short curly wool. The crown of the head, the upper part of the neck, the back, and thighs are of a peculiar reddish-yellow hue, which the natives call _color de vicuña_. The lower part of the neck and the inner parts of the limbs are of a bright ochreous colour, and the breast and lower part of the body white. During the wet season the vicuña browses on the scanty vegetation of the Cordilleran ridges. He never ventures up to the bare rocky summits, for his hoofs, being accustomed only to the yielding sward, are very soft and tender. He lives in herds, consisting of from six to fifteen females, and one male, who is the protector and leader of the herd, and who, while the females graze, stands a few paces apart, carefully watching over their safety. At the approach of danger he gives a signal, consisting of a kind of whistling sound and a quick movement of the foot. Immediately the herd draws close together, each animal stretching out his head in the direction of the impending alarm. Then they take to flight; first moving leisurely and cautiously, but quickening their pace to the utmost degree of speed; whilst the male vicuña, who covers the retreat, occasionally halts to observe the motions of the enemy. The females reward his devotion by the warmest affection and fidelity, and will suffer themselves to be killed or captured rather than desert him.