BROADCASTS.com

b"Sign up for our mailing list! We also have t-shirts and mugs with our logo!\\n\\nHere we go. It's the big one, the Cretaceous-Paleogene extinction event!\\n\\n\\n\\nFurther reading:\\n\\nHow Birds Survived the Asteroid Impact That Wiped Out the Dinosaurs\\n\\nHow an asteroid ended the age of dinosaurs\\n\\nExtinction event that wiped out dinosaurs cleared way for frogs\\n\\nHow life blossomed after the dinosaurs died\\n\\n66-million-year-old deathbed linked to dinosaur-killing meteor\\n\\nShow transcript:\\nWelcome to Strange Animals Podcast. I\\u2019m your host, Kate Shaw.\\nHere it is, the extinction event episode that everyone\\u2019s been waiting for, or at least that everyone knows about. It\\u2019s the one that killed off the dinosaurs and ushered in the age of mammals. It\\u2019s probably the one we know most about and it\\u2019s certainly the one we have the most paintings of, usually of a T. rex staring into the sky at an approaching comet.\\nIn episode 227 we talked about the end-Permian extinction event, which took place about 250 million years ago. The Cretaceous-Paleogene extinction event, or end-Cretaceous, took place just over 66 million years ago, which means that for almost 200 million years there was more or less smooth sailing in the world. Dinosaurs evolved during that time, and I think we can all agree that dinosaurs are fascinating animals.\\nThe largest terrestrial animals ever to live were dinosaurs, specifically the sauropods. Sauropods were just unimaginably huge. They were like walking buildings that ate plants, and even that doesn\\u2019t give a good idea of their size. Some sauropods had extremely long tails as well as very long necks, which increased their length. Right now the largest sauropod known was probably Argentinosaurus that might have grown as long as 118 feet, or 36 meters, but paleontologists keep finding bigger and bigger sauropods. Some sauropods had extremely long necks that they held up like a giraffe. The tallest was probably Barosaurus, estimated as being 72 feet tall, or 22 meters. And we won\\u2019t even get into estimates of how much these massive animals weighed. They make the biggest elephant that ever lived look like a toy elephant.\\nSauropods ate plants, with the low-necked species eating low-growing plants and the high-necked species eating tree leaves, although even saying that much is controversial. There\\u2019s a lot we don\\u2019t know about sauropods in general, since most sauropod fossils are incomplete and many species are only known from one or a few bones. But we do know some surprising things about sauropods. We have a lot of sauropod tracks, which helps us understand how their feet looked and whether they had claws, but it also tells us that some species of sauropod traveled in herds. Paleontologists do generally agree that many sauropods migrated, since animals that big would soon exhaust all the food in one area if they didn\\u2019t.\\nSauropods were extremely successful and lived all over the world. There were plenty of sauropods alive 66 \\xbd million years ago, and then\\u2026there were no sauropods alive ever again.\\nThese days, there\\u2019s so much evidence that a massive asteroid killed off the dinosaurs that pretty much everyone agrees, but when the idea was first proposed in 1980, it was extremely controversial. When I was a kid I remember reading dinosaur books that still said the extinction of the dinosaurs was a mystery but that many scientists thought it was due to disease or volcanoes.\\nThe asteroid strike hypothesis was proposed by the physicist Luis Alvarez and his son, Walter. They worked with a small team of other scientists, including two chemists, Helen Michel and Frank Asaro, to investigate a strange anomaly in rock strata. Rocks dating to the end of the Cretaceous period and the beginning of the Paleogene period are separated by a thin layer of clay that\\u2019s visible throughout the world, or at least wherever the rocks remain and can be examined. It\\u2019s called the Cretaceous-Paleogene boundary, or K-Pg boundary,"