Scientists who study brains can determine what capacity our brains have for using the five senses. Paleontologists can do the same thing using dinosaur skull fossils. Stephan Lautenschlager and Emily Rayfield of the University of Bristol led a recent study that investigated the skulls of dinosaurs known as therizinosaurs in order to glean more information about how much dinosaurs used their senses. Therizinosaurs are a type of theropod, a family that also encompasses the infamous dinos Velociraptor and Tyrannosaurus rex. Therizinosaurs had up to 23 foot long bodies, sported a mane of feathers, and had unusually long, sharp talons on their hands. Though not too many therizinosaur fossils have been unearthed, Lautenschlager’s study centered on the skull of one called Erlikosaurus andrewsi, a 10 to 13 foot-long therizinosaur who lived in Mongolia 90 million years ago. Using CT scanning and 3D computer visualization to infer from the brain cavity what different sensory organs looked like, the research team determined that the skull would have carried a large forebrain, indicating that therizinosaurs had large sensory organs and probably heightened senses of smell, hearing, and balance. This was a surprising find given that therizinosaurs ate plants. Acute senses of smell and hearing are usually attributed to meat-eaters, who had to be cunning in order to find and kill prey. However, Erlikosaurus andrewsi’s close relation to T. rex and Velociraptor, whose ferocious predatory abilities were a result of high-functioning sensory organs, indicates that therizinosaurs may have inherited the senses from their common ancestor. The researchers surmise that the veggie-eating therizinosaurs used acute senses in order to escape predators or find tasty food. A study in 2011 by researchers from the University of Calgary, the Royal Tyrell Museum and Ohio University used the same principles of brain size versus sense ability to determine that dinosaurs like Erlikosaurus andrewsi who had strong senses of smell passed this on to the earliest birds. (Read more about this study at www.sceincedaily.com)
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Find the study in the journal PLoS ONE.