The largest animal of this family is the huanacu. It measures five feet from the bottom of the hoof to the top of the head, and three feet three inches to the shoulders. In form it so nearly resembles the llama, that until a very recent period, zoologists were of opinion that the llama was an improved species of the huanacu, and that the latter was the llama in its wild state. In the "Fauna Peruana" I have explained the erroneousness of this opinion, and described the specific differences existing between the two animals. On the neck, back, and thighs the huanacu is of a uniform reddish-brown color. 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 face is dark grey, and the lips of a clear white. Of the huanacus there are not those varieties which are found among the llamas and the alpacos. The wool is shorter and coarser than that of the llama, and it is of nearly uniform length on all parts of the body.
The huanacus live in small herds of five or seven, seldom exceeding the latter number. In some districts they are very shy, and retreat when any one approaches. If taken very young they may be tamed; but they are always ready to fall back into their wild state. It is with great difficulty they can be trained as beasts of burthen. In the menageries of Europe, huanacu brought from Chile are frequently represented to be llamas.
The vicuña is a more beautiful animal than any of those just described. Its size is between that of the llama and the alpaco. It measures from the sole of the foot to the top of the head four feet one inch, and two and a half feet to the shoulders. The neck is longer and more slender than in either of the other relative species; and from them the vicuña is also distinguished by the superior fineness of its 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, called by the people of the country _color de vicuña_. The lower part of the neck, and the inner parts of the limbs, are of a bright ochre color, and the breast and lower part of the body are white.
During the rainy season the vicuña inhabits the ridges of the Cordillera, where some scanty vegetation is to be found. It never ventures up to the naked rocky summits, for its hoofs being accustomed only to turfy ground, are very soft and tender. It lives in herds, consisting of from six to fifteen females, and one male, who is the protector and leader of the herd. Whilst the females are quietly grazing, the male stands at the distance of some paces apart, and carefully keeps guard over them. At the approach of danger he gives a signal, consisting of a sort of whistling sound, and a quick movement of the foot. Immediately the herd draws closely together, each animal anxiously stretching out its head in the direction of the threatening danger. They then take to flight; first moving leisurely and cautiously, and then quickening their pace to the utmost degree of speed; whilst the male vicuña who covers the retreat frequently halts, to observe the movements of the enemy. The females, with singular fidelity and affection, reward the watchful care of their protector. If he is wounded or killed, they gather round him in a circle, uttering their shrill tones of lamentation, and they will suffer themselves to be captured or killed, rather than desert him by pursuing their flight. The neigh of the vicuña, like that of the other animals of its class, resembles a short, sharp whistle. But when the shrill sound vibrates through the pure Puna air, the practised ear can readily distinguish the cry of the vicuña from that of the other animals of the same family.