Monkeys Reached South America by Rafting on Vegetation From Africa
"It seems like the only way is through one of these Hail Mary dispersals where there are some of these mammals, maybe after a storm, maybe they're on a raft of vegetation, sometimes big chunks of the coast, trees and grass and all kinds of stuff can be ripped apart, thrust out into the ocean, and can actually travel the currents for many weeks and then land somewhere in a distant land. And that seems to be how the rodents and the primates got to South America."
About this episode
Steve Brusatte, paleontologist at the University of Edinburgh and consultant on Jurassic World films, traces the complete evolutionary history of dinosaurs and their descendants in this comprehensive interview. Brusatte begins with the Permian extinction 250 million years ago, the worst in Earth's history, which killed 95% of all species when Siberian supervolcanoes triggered runaway greenhouse warming. From the survivors emerged small reptiles that would become dinosaurs. He explains how dinosaurs remained second-tier players for tens of millions of years until another mass extinction at the end of the Triassic wiped out their crocodile competitors, allowing dinosaurs to dominate. Brusatte corrects popular misconceptions about T-Rex, revealing it could only run 10-15 mph contrary to Jurassic Park depictions, had arms the size of human arms despite being bus-sized, and likely had feathers. Most controversially, fossil evidence proves many dinosaurs, including tyrannosaur ancestors, were covered in feathers. The asteroid that struck 66 million years ago created a nuclear winter lasting up to a decade, killing everything larger than a husky dog on land. Only small beaked birds survived among dinosaurs because they could eat seeds during the prolonged darkness. Brusatte's research on mammal evolution reveals that mammal brains actually got relatively smaller in the first 10 million years after the asteroid as bodies rapidly expanded to fill ecological niches. DNA evidence shows South American monkeys and rodents rafted across the Atlantic from Africa on storm vegetation. He discusses the ethics of cloning woolly mammoths, noting it may soon be possible but raises questions about returning ice-age species to a radically altered world humans created. Throughout, Brusatte emphasizes that modern birds are living dinosaurs, the only lineage to survive to the present day.
Key takeaways
- The Permian extinction 250 million years ago killed 95% of species when Siberian supervolcanoes caused runaway greenhouse warming, allowing dinosaur ancestors to emerge
- T-Rex could only run 10-15 mph, not fast enough to catch a jeep as depicted in Jurassic Park, but had sophisticated senses and intelligence
- Fossil evidence proves many dinosaurs including tyrannosaur ancestors had feathers covering their bodies, contradicting popular scaley depictions
- The asteroid impact 66 million years ago created a nuclear winter lasting up to a decade that killed all dinosaurs except small beaked birds
- Mammal brains got relatively smaller after the asteroid as bodies rapidly expanded from cat-size to cow-size within a million years
- DNA analysis reveals South American monkeys and rodents rafted across the Atlantic from Africa on vegetation, explaining a major evolutionary puzzle
- Cloning woolly mammoths may soon be scientifically possible but raises ethical questions about resurrecting species adapted to extinct ice-age environments humans destroyed