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Part of the scientific method involves making mistakes and correcting them. Here are some interesting and sometimes goofy mistakes made by paleontologists through the years, and how the mistakes were corrected.\n\nIguanodon did not actually look like this (left). It looked like this (right):\n\n \n\nPterosaur did not actually look like this (left). It looked like this (right):\n\n \n\nElasmosaurus did not actually look like this (left). It looked like this (right):\n\n \n\nApatosaurus/brontosaurus did not actually look like this (left). It looked like this (right):\n\n \n\nStegosaurus did not actually look like this (left). It looked like this (right):\n\n\n\nGastornis did not actually look like this (left). It looked like this (right):\n\n \n\nThose are Gastornis's footprints:\n\n\n\nShow transcript:\n\nWelcome to Strange Animals Podcast. I\u2019m your host, Kate Shaw.\n\nPaleontology is the study of fossils, and really it\u2019s only been a discipline for a little over a century. Back in the 19th and early 20th centuries, even experts made major mistakes in preparing and assembling fossil skeletons, and dishonest amateurs made deliberate errors so their fossil animals looked bigger or scarier. Many of these mistakes or hoaxes were displayed in museums, sometimes for decades.\n\nI found so many interesting examples during my research that I decided to split the episode into two. This week we\u2019ll learn about some paleontological mistakes and what the fossil animals really looked like when they were alive. Next week we\u2019ll look at the frauds and hoaxes.\n\nWe\u2019ll start with Iguanodon, a dinosaur that lived around 125 million years ago in what is now Europe. It ate plants and was fairly common, with a number of species now known to science. The biggest could grow as much as 43 feet long, or 13 meters. It had teeth that resemble an iguana\u2019s, which is how it gets its name, and a beak probably covered in keratin that it used to clip through tough plants. It probably mostly walked on two legs and browsed from trees, but its front legs were long and it might have spent at least some of its time on all fours. But the most interesting thing about Iguanodon was its hands. Its little finger was slender and usually longer than the others and many researchers think it was used for handling food and other objects. The first finger, which is equivalent to a thumb, wasn\u2019t so much a digit as just a big spike. It\u2019s called a thumb spike and no one\u2019s sure what it was for. It might have been used for defense, but it might also have been used to help dig up plants. Maybe it was used for both. But it was the source of an embarrassing mistake that many paleontologists made for years.\n\nIguanodon came to the attention of science in 1822 when a medical doctor in Sussex, England found some fossilized teeth. No one was sure what kind of animal the teeth belonged to, although guesses ranged from a crocodile to a rhinoceros. In 1824 the doctor, Gideon Mantell, noted the teeth\u2019s resemblance to iguana teeth, but so big that he estimated Iguanodon must have been almost 60 feet long, or 18 meters. He also thought Iguanodon looked like an iguana.\n\nIn 1834 more Iguanodon fossils came to light in a quarry and Mantell bought them. This incomplete skeleton included a thumb spike, but Mantell didn\u2019t know where it belonged. He thought it was a horn, so when he made a drawing of the living animal, he placed the thumb spike on the nose.\n\nAnd there it stayed, despite other fossils found with the thumb spike in place on the hand, and despite other scientists pointing out that they didn\u2019t think Iguanodon had a horn on its nose. It wasn\u2019t until 1882 that the nose horn vanished for good and Iguanodon started looking more like itself.\n\nSimilarly, pterosaurs have been misunderstood since the very beginning, with a lot of frankly ridiculous suggestions made about them. To be fair, they are really strange animals and nothing like any animal living today.