The background on Monkeys in the Americas
When monkeys landed in South America 37 or more million years ago, the long-isolated continent already teemed with a menagerie of 30-foot snakes, giant armadillos and strange, hoofed mammals. Over time, the monkeys forged their own niches across the New World, evolved new forms and spread as far north as the Caribbean and as far south as Patagonia.
Duke University evolutionary anthropologist Richard Kay applied decades' worth of data on geology, ancient climates and evolutionary relationships to uncover several patterns in primate migration and evolution in the Americas. The analysis appears online this week in the journal Molecular Phylogenetics and Evolution.
Today, more than 150 species of monkeys inhabit the New World, ranging in size from the pygmy marmoset, which weighs little more than a bar of soap, to the muriqui, a long-limbed monkey that tips the scales at 25 pounds.
"We know from molecular studies that the monkeys have their closest relatives in Africa and Asia -- but that doesn't explain how they got to South America, just that they did," said Kay, a professor in the evolutionary anthropology department and division of earth and ocean sciences at Duke.
South America split from Africa long before monkeys evolved, and the scarcity of monkey ancestors in the North American fossil record makes a southward migration highly unlikely. That's led scientists to speculate that the animals made the ambitious transatlantic crossing on a vegetation raft, perhaps hurled seaward by a powerful storm. Or, they could have hopped more gradually, using islands that now lie at the bottom of the ocean.
Squirrel monkey image via Shutterstock.
Read more at ScienceDaily.