The rivers which bound the plain to the south--the Arauca, the Apure, and the Pajara--gradually swell, and now Nature compels the same animals, which in the first half of the year panted with thirst on the dry and dusty soil, to adopt an amphibious life. A portion of the Steppe now assumes the aspect of a vast inland sea.[93] The brood mares retire with their foals to the more elevated banks, which rise like islands above the watery expanse. Every day the dry space grows smaller. It is a miniature reproduction of the Noachian Deluge. The animals, crowded together, swim about for hours in quest of other pasture, and feed sparingly on the tops of the flowering grasses that spring above the seething surface of the turbid waters. Many foals are drowned, and many are surprised by the crocodiles, killed by a blow from their powerful tails, and devoured. It is no uncommon thing to see the marks of these monsters' cruel teeth on the legs of horses and cattle which have narrowly escaped from their blood-thirsty jaws. Such a sight reminds the thoughtful observer of that capability of adaptation to the most varied circumstances with which the all-powerful Creator has endowed certain animals and plants.[94] The Pampas of Pernambuco and Buenos Ayres have three times the superficial area of the Llanos of Venezuela. So great is their extent, that while forests of palms border them on the north, they are covered with snow in the south, during a great part of the year, like the northern Steppes of Tartary. According to the climatic divisions generally adopted, these regions belong to the Temperate Zone; but in truth they comprehend a great variety of climates. Their character is not less grand or original than that of the Llanos which precede them. "The Pampas," says an American writer, "surpass in majesty all the marvels of the new continent, and yet they astonish the traveller by the air of abandonment and sadness which is impressed upon them, especially in the low country watered by the Plata. Traces of life are there infrequent; still rarer are the objects which attract attention. Here, at the bottom of a crevasse, a cactus conceals its head bristling with spines; there, a solitary tree rises majestically toward heaven. Sometimes, upon the plain, the eye discovers the monstrous skeleton of an animal which flourished in those remote times when the Alps still slept in the depths of ocean, and dreamed not of blending their snow-burdened peaks with the clouds. The Pampas serve as the burial-place for races of gigantic men, now extinct, who seem to issue from their silent graves in testimony to the former being of vanished generations, and to bear witness to the Creator of all things. Above your head, and far away in the azure of heaven, you perceive a black point; it is a condor describing slowly its sinister circles. In the distance passes and disappears the ungainly figure of an ostrich. The inexpressible charm of these solitudes is their absolute freedom.