What the thagomizer?! with ReBecca Hunt-Foster

If something wants to eat you, you have three options: get so big that knocking you over is not worth the trouble, get fast enough to leave, or make yourself so expensive to attack that nobody bothers. Plenty of dinosaurs took the third one, and they did it by growing bone inside their own skin. Not armour they put on, but armour they were, down to bony eyelids in the case of Ankylosaurus. This week’s word is thagomizer, the cluster of spikes on the end of a Stegosaurus tail, and it is the only piece of dinosaur anatomy named by a newspaper cartoon. Gary Larson drew one in The Far Side in 1982, with a caveman lecturing his class and crediting “the late Thag Simmons”. Thag Simmons never existed. Palaeontologists liked the word too much to let that stop them, and it stuck. It describes something genuinely dangerous: there is an Allosaurus bone with a thagomizer-sized hole punched through it, which had begun to heal before the animal died. Fresh from the Dig is all armour. Two vertebrae collected in the 1950s, filed as sauropod and left in a display case, turn out at 27 and a half and 29 inches to belong to the largest Stegosaurus known. Vectipelta barretti, an armoured dinosaur from the Isle of Wight, is named after Professor Paul Barrett of the Natural History Museum by colleagues who wanted to honour his work on exactly this kind of dinosaur. And Sophie, about 85 per cent of a skeleton and the most complete Stegosaurus ever found, whose skull was the first preserved well enough to show what a Stegosaurus head actually looked like. She weighed 1.6 tonnes and was not fully grown. Lauren and Cassius are joined by Dr ReBecca Hunt-Foster, the monument palaeontologist at Dinosaur National Monument in Utah, whose office is essentially a cliff with about 1,500 dinosaur bones still stuck in it. She explains how a Diplodocus turned up under a car park that was being repaved, and why more of it was deliberately left in the ground for whoever digs next; how clam fossils found open rather than shut are the evidence for the drought that killed the animals in the quarry; and how a single foot was enough to name a new species. Her advice on armour: cover your back, your sides and your neck. Freya, who is nine and from Newcastle, wants to know whether the plates on a Stegosaurus were for fighting or for showing off, and palaeontology has been arguing about it for a century. Then it is Build a Dino Lab, where one real fact becomes one real piece of the perfect dinosaur. Week four is tank or knight, and Lauren goes for plates, shoulder spikes and a thagomizer, because full ankylosaur armour on a dinosaur built to run would slow it to a crawl. Next week, where all of this lived, and a scientist whose fossils are smaller than a grain of sand.See omnystudio.com/listener for privacy information.