The South American pampa stretches from the Andean foothills to the Atlantic coast. Once an ancient seabed, it is about 750,000 square kilometers in size. The western pampa is covered in shingle and sand, and the eastern half, by deposits of estuary silt washed down from the highlands during periods of massive floods.
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Smilodon populator - Having evolved in North America, Smilodon populator migrated to South America during the late Pleistocene epoch. This was the largest cat of the sabertooth species and weighed an average of 250 kilos, making it one of the largest felids; the tiger, at 300 kilos, currently ranks as the biggest cat. High shoulders and a sloped back gave it the appearance of a modern hyena. These cats became extinct about 10,000 years ago, a time period coinciding with the decline of the large herbivores throughout the Americas.
