The biogeographic origins of the Pilosa are still unclear, but they can be traced back in South America as far as the early Paleogene (about 60 million years ago, only a short time after the end of the Mesozoic Era). The presence of these animals in Central America and their former presence in North America is a result of the Great American Interchange. A number of sloths were also formerly present on the Antilles, which they reached from South America by some combination of rafting or floating with the prevailing currents.