Late Cenozoic Mammal Dispersals between the Americas

Abstract

For nearly a century the Great American Interchange has been widely acclaimed as one of the most remarkable experiments ever performed by nature. The only problem with such grand billing is that nature, as usual, has not provided a complete set of results. A long-term effect by many investigators has gradually yielded many fragmentary documents. While these indicate the outlines of the great experiment, the exact details and the precise processes often remain speculative and key data sets are often still incomplete. The appropriate response, as in any historical science, is to search for more documents of appropriate age and geography. Such efforts, by scientists and explorers in both American continents, lead continually toward a more comprehensive record of organisms and environments in the Americas during the past 10 million years. The history of the Great American Biotic Interchange many never be completely revealed; yet, in retrospect, progress in compiling relevant documents seems, if anything, to be accelerating in this half century beyond what it was in the first half century.