The formation of a land bridge across the Isthmus of Panama between North and South America had profound impact on the fauna of these continents. Many North American animals invaded the southern continent and a few South American animals migrated north.


A shift in the Caribbean tectonic plate joined North and South America, providing a land bridge for mammals to migrate across.

South American mammals found in North American Pliocene sediments include giant sloths, armadillos, and porcupines.