Great American Interchange

When the Great American faunal exchange of numerous animal forms between North and South America is referred to, which took place after the formation of the Isthmus of Panama in the Pliocene about 3 million years ago. The ancestors of many today typical for South America mammals such as camels, cats, dogs, peccaries, tapirs and small bear wandered at that time from North America. But even some of today's North American mammal species such as armadillos and opossums, as well as the later extinct giant sloths and glyptodons reached during the exchange from South to North America.

The isolated development of the South American fauna

Before about 100 million years ago South America had begun to separate from the other continents. The wildlife developed in the following course of history over a very long period completely independent from other continents. Only a few forms, such as rodents and primates reached as so-called island hopping on the isolated continent, the otherwise one-off orders of mammals ( Sparassodonta, Notoungulata, Litopterna, Astrapotheria ) was settled.

The formation of the land bridge and the consequences

During the Pliocene, about 3 million years ago, a stable land bridge to North America, the Isthmus of Panama was formed. Numerous animal species spread across the land bridge from North to South, but also vice versa. This large faunal led to the disappearance of many native animal forms, especially in South America, which were replaced by other forms of animals with similar ecological niches. The shrews, cats, dogs, bears, raccoons, raccoon, deer, peccaries, horses, tapirs, gomphotheres, rabbits, squirrels and Cricetiden migrated from North America to South America a. Many of the native mammals disappeared because they were replaced by the new arrivals. Among the survivors were the Xenarthra, opossums, rodents and primates, as well as the Toxodonten and Macrauchenien. Among the families who immigrated from South America to North and Central America including giant sloths ( Megatheriidae, Mylodontidae ), the glyptodons, the armadillos, the anteaters, capybaras, the porcupine, the possums and the later extinct Toxodonten. Even the terror bird Titanis walleri immigrated to North America, with finds, inter alia, in Florida.

Swell

• LG Marshall: Land Mammals and the Great American Interchange. In: Sigma Xi (ed. ): American Scientist. 76, No. 4, July - August 1988, pp. 380-388. Accessed on June 6, 2009.

• Geozoologie
• America