Next to the guanaco in interest if not in utility is the panther of Patagonia, the _felis concolor_ of the naturalist. Nowhere in the world does the great tree-climbing cat reach greater size or accumulate more fat than on the treeless deserts of the far south. Specimens from eight to nine feet long over all are frequently seen. Though, perhaps, rather lighter in color, they are in all other respects exactly like the panthers of the United States. How it happened one cannot even guess, but the panther is known very much better in the desert than in the United States. Rarely can one read a story of the panther in the States without seeing something about its terrible ferocity toward human beings, while the stories of the panther that comes out of the woods to play with the lonely wayfarer as a cat plays with a mouse, that it may at last crush and eat him, are enough to make the flesh of the unlearned reader creep on his bones. On the desert of Patagonia there are more panthers in proportion to the area and the numbers of other kinds of animals than in any other region of the world. The lonely wayfarer is not often found there afoot, but men have been on the desert unmounted, and the panthers have come to play around them, too. But it is not as a predatory cat that they come. It is as a playful kitten. Individual panthers play by themselves--old ones as well as young--by the hour. They will chase and paw and roll an upturned bush, or a round rock, or any moving thing, and lacking that will pretend to sneak up on unwary game, crouching the while behind a bush, or rock for concealment, to spring out at last and land on a hump of sand or a shadow. Then they turn around and do the same thing over again. When it is in this frame of mind if a lone human being comes along the panther is as glad to see him as a petted cat to see its mistress. It purrs and rolls over before him, and gallops from side to side, and makes no end of kitten-like motions, and all because of the exuberance of its youthful spirits. I know that the average reader, accustomed to the Fenimore Cooper sort of novels, will think this an exaggeration, but the plainsmen of all Argentina call the panther by a name that means "the friend of man," and that too in spite of the havoc it makes among their sheep.