Understanding St. Vincent’s Volcanic Eruption Since April 9th, the Caribbean island of St. Vincent has been rocked by eruptions at the La Soufrière volcano. Over the last week, plumes of ash and gas have rained down on the island, and dense masses of debris, called pyroclastic flows, are destroying everything in their path. Tens of thousands of residents have been evacuated.   La Soufrière has only erupted a handful of times in recorded history, most recently in 1979. But the volcano has a deadly legacy, both for St. Vincent and beyond. Joining Ira to discuss La Soufrière’s impact is Jazmin Scarlett, a social and historical volcanologist based in Newcastle upon Tyne, England.     How Many T-Rexes Once Roamed the Earth? Maybe Billions Tyrannosaurus rex is probably one of the most popular dinosaurs, but there’s still a surprising amount of mystery surrounding these animals, including basic facts like how many there once were. One team of researchers recently decided to figure out how many T-rexes existed during their long reign. The group of scientists did some back of the envelope calculations and came up with a rough population size estimate of 2.5 billion T-rexes over 2.5 million years, with an error rate of plus or minus a factor of 10. Their results were published in the journal Science. Paleontologist Charles Marshall, who was one of the authors on the study, joins Science Friday to explain how they combined fossil records and data from present day animals to calculate the population density of these charismatic carnivores.     Pterosaurs Had A 40-Foot Wingspan And A Giraffe-Like Neck During the age of dinosaurs, there were all sorts of creatures flying through the air with different body shapes and sizes. One of those was a flying reptile called the azhdarchid pterosaur. This stork-like creature had the neck of a giraffe, and a 40-foot wingspan. A group of scientists wanted to know more about the internal structure of the pterosaur’s long neck. Their results were published in the journal iScience. Paleontologist Nizar Ibrahim talks about what this pterosaur can tell us about the evolution of flight, and how it might inform our understanding of other prehistoric animals and dinosaurs found in Africa.     SciFri Book Club Digs Into The Foods We’ve Loved To Death Did humans kill off the mammoths? What happened to the mysterious Roman herb, known as silphium, that was once worth its weight in gold? Can lab-grown meats help save what’s left of our planet’s biodiversity from climate change and habitat loss? Food geographer Lenore Newman sets out to answer these questions, and more, in her 2019 book, Lost Feast: Culinary Extinction and the Future of Food, this spring’s Science Friday Book Club pick. In the book, she eats her way around the world and through history, examining the stories of the dodo bird, Icelandic dairy cows, the passenger pigeon, the Bartlett pear—and all its cousins—and the food species threatened by the sixth great mass extinction. SciFri producer and Book Club captain Christie Taylor talks to Newman about some of the surprises from her research, and what might be next for the foods we love.