WEBVTT - BrainStuff Classics: How Did Plesiosaurs Swim So Efficiently?

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<v Speaker 1>Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff,

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<v Speaker 1>Lauren Volga bomb here with a classic episode from our

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<v Speaker 1>erstwhile host, Christian Sagar. Lots of animals that roamed the

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<v Speaker 1>Earth during the time of the dinosaurs weren't quite like

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<v Speaker 1>anything we humans have ever seen, including many that aren't

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<v Speaker 1>classified as dinosaurs, like the plesiosaurs. Hey brain Stuff, it's

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<v Speaker 1>Christian Saga. From two hundred and twenty to sixty six

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<v Speaker 1>million years ago, a strange order of marine reptiles called

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<v Speaker 1>plesiosaurs roamed Earth's oceans. Though they were a diverse bunch

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<v Speaker 1>in many respects, every known species did share one major trait.

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<v Speaker 1>They all had four broad, paddle like flippers, and in

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<v Speaker 1>most cases, the hind pair almost looked like a duplicate

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<v Speaker 1>of the front set, both in size and shape. That

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<v Speaker 1>makes plesiosaurs, which were not dinosaurs but lived at the

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<v Speaker 1>same time, unique among ocean going vertebrates. That's because no

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<v Speaker 1>other marine reptile or mammal extinct or extent sports four

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<v Speaker 1>flippers of similar size. So how did this unique body

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<v Speaker 1>plan work? Researchers might have just found the answer. On August,

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<v Speaker 1>an international team of scientists published a new study on

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<v Speaker 1>plesiosaur locomotion headed by paleontologists Luke Musket. The group used

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<v Speaker 1>measurements from a pair of British species to construct two

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<v Speaker 1>replica flippers, one four limb and one hind limb with

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<v Speaker 1>three D printing technology. These were affixed to a custom

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<v Speaker 1>built robot which moved the replicas around in a tank

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<v Speaker 1>of water to see exactly how the paddles would churn

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<v Speaker 1>things up. Musket and company released colorful dyes into the

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<v Speaker 1>tank as well and tracked their motion through water. Afterwards,

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<v Speaker 1>the scientists put the robotic legs through numerous simulations designed

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<v Speaker 1>to test out different swimming styles. They found that the

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<v Speaker 1>most energy efficient stroke called for both flippers to work

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<v Speaker 1>in concert. When the front limb flapped in this test,

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<v Speaker 1>it created two vortices in the water. As the current

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<v Speaker 1>pushed these backward, the hind flipper weaved in between them.

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<v Speaker 1>By capitalizing on the wake generated by its frontal counterpart,

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<v Speaker 1>The rear limb made its own flapping motion si more powerful,

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<v Speaker 1>and this finding actually contradicts a study which argued that

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<v Speaker 1>plesiosaurs swam like sea turtles, using their four limbs to

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<v Speaker 1>push themselves forward while their rear paddles acted as rudders

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<v Speaker 1>using the robot Muskets team also tested this existing hypothesis.

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<v Speaker 1>They found that the rear paddles tended to produce drag

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<v Speaker 1>if kept in a stationary position, but by using all

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<v Speaker 1>four paddles to actively generate thrust, a plea asiosaur could

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<v Speaker 1>move more efficiently. However, the co authors acknowledge that, like

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<v Speaker 1>most aquatic animals, plesisaurs probably adjusted their swimming style as

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<v Speaker 1>the situation called for it. Furthermore, the study is complicated

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<v Speaker 1>by the fact that several Plesia saur species had four

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<v Speaker 1>limbs that were noticeably longer than their rear ones or

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<v Speaker 1>vice versa. Looks like follow up research will have to

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<v Speaker 1>take species specific data into account. Today's episode was written

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<v Speaker 1>by Mark Mancini and produced by Dylan Fagan and Tyler Clang.

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<v Speaker 1>For more on this and lots of other unusual topics,

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<v Speaker 1>visit how stuff works dot com. Brain Stuff is production

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<v Speaker 1>of iHeart Radio. For more podcasts my heart Radio, visit

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