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Sign up for our mailing list! We also have t-shirts and mugs with our logo!\n\nFurther reading:\n\nMillion-year-old mammoth genomes shatter record for oldest ancient DNA\n\nMammoth Genome Project (with pictures of cave art and ancient carvings of mammoths)\n\nThe most famous cave painting of a mammoth, from a cave in France:\n\n\n\nSivatherium:\n\n\n\nShow transcript:\nWelcome to Strange Animals Podcast. I\u2019m your host, Kate Shaw.\nIt\u2019s the last Monday of 2021, which means the very last extinction event episode. There\u2019ve been way more extinction events in earth\u2019s long history than the five we\u2019ve covered this year, and not all of the extinction events I chose to highlight were even necessarily the biggest. This one, for instance.\nYou may have noticed a pattern when I talk about ice age megafauna. So many animals went extinct about 11,000 years ago. That\u2019s this week\u2019s topic, the end-Pleistocene extinction event.\nThe Pleistocene is often called the ice age, or ice ages since it consisted of multiple glaciation periods separated by warmer times when the glaciers would retreat for a while. It started roughly 2.6 million years ago and is considered to have ended 11,700 years ago. Keep in mind, as always, that these dates are just a shorthand to help scientists refer to changes in earth\u2019s history. There was no one day where the sun rose and everything had abruptly changed from one era to another. The changes took place over a long time, hundreds of thousands of years, with different parts of the world changing more quickly or slowly than others depending on local conditions.\nAt the beginning of the Pleistocene, the world\u2019s continents were roughly in their present positions. Two continental plates in what is now Central America collided very slowly over millions of years, which caused the land to buckle up and magma to erupt through the earth\u2019s crust as volcanoes. The volcanoes created islands in the Central American Seaway, a section of ocean between North and South America that connected the Atlantic and Pacific Oceans. By around 5 to 10 million years ago, the volcanoes and land continued to be pushed up, and sediment from rivers filled in between them, until finally instead of islands there was actual land that connected North and South America. That land is called the Isthmus of Panama and it allowed the great American interchange where animals from North America could cross into South America, and vice versa, but that\u2019s a topic for another episode.\nAnother result of the Isthmus of Panama\u2019s formation is that the Atlantic and Pacific Oceans were more separated. Instead of ocean currents circulating between North and South America, they were cut off and new currents formed. Ocean currents help distribute warm water to colder areas and cold water to warmer areas, which affects air and land temperatures too. Around 2.5 million years ago, the ocean current changes had changed the entire overall temperature of the earth, making it much cooler overall. That wasn\u2019t the only cause of the ice ages, but it was a major factor.\nThe earth gradually became cooler and dryer, a process that had already started due to other causes and was accelerated by the ocean current changes. As the global temperature dropped, more and more water was locked up in huge glaciers called ice sheets, at first around the poles and then farther south. This meant sea levels dropped a lot. North America was connected to Asia by a stretch of grassland steppe called Beringia that had formerly been submerged.\nAs the temperatures dropped and the climate changed, animals and plants had to adapt. The ancestors of modern elephants had lived in Africa for millions of years, but they started migrating to other parts of the world around 3 million years ago. Because they were already big, they were good at retaining heat in their bodies and became quite successful as the climate grew cooler and cooler. They evolved long hair to stay even warmer and spread throughout much o...