Speaker 1: Welcome to brain stuff from how stuff Works. Hey, brain stuff,
Speaker 1: It's Christian saga. From two hundred and twenty to sixty
Speaker 1: six million years ago, a strange order of marine reptiles
Speaker 1: called plesiosaurs roamed Earth's oceans. Though they were a diverse
Speaker 1: bunch in many respects, every known species did share one
Speaker 1: major trait. They all had four broad, paddle like flippers,
Speaker 1: and in most cases the hind pair almost looked like
Speaker 1: a duplicate of the front set, both in size and shape.
Speaker 1: That makes plesiosaurs, which were not dinosaurs but lived at
Speaker 1: the same time, unique among ocean going vertebrates. That's because
Speaker 1: no other marine reptile or mammal extinct or extent sports
Speaker 1: four flippers of similar size. So how did this unique
Speaker 1: body plan work. Researchers might have just found the answer.
Speaker 1: On aug an international team of scientists published a new
Speaker 1: study on plesiosaur locomotion. Headed by paleontologists Luke Musket. The
Speaker 1: group used measurements from a pair of British species to
Speaker 1: construct two replica flippers, one four limb and one hind
Speaker 1: limb with three D printing technology. These were affixed to
Speaker 1: a custom built robot which moved the replicas around in
Speaker 1: a tank of water to see exactly how the paddles
Speaker 1: would turn things up. Musket and company released colorful dyes
Speaker 1: into the tank as well, and tracked their motion through water. Afterwards,
Speaker 1: the scientists put the robotic legs through numerous simulations designed
Speaker 1: to test out different swimming styles. They found that the
Speaker 1: most energy efficient stroke called for both flippers to work
Speaker 1: in concert. When the front limb flapped in this test,
Speaker 1: it created two vortices in the water. As the current
Speaker 1: pushed these backward, the hind flipper weaved in between them.
Speaker 1: By capitalizing on the wake generated by its frontal counterpart,
Speaker 1: the rear limb made its own flapping motion six more powerful,
Speaker 1: and this finding actually contradicts a study which argued that
Speaker 1: plesiosaurs swam like sea turtles, using their four limbs to
Speaker 1: push themselves forward while their rear paddles acted as rudders.
Speaker 1: Using the robot, muskets team also tested this existing hypothesis.
Speaker 1: They found that the rear paddles tended to produce drag
Speaker 1: if kept in a stationary position, but by using all
Speaker 1: four paddles to actively generate thrust, a plesiosaur could move
Speaker 1: more efficiently. However, the co authors acknowledge that, like most
Speaker 1: aquatic animals, plesi asaurs probably adjusted their swimming style as
Speaker 1: the situation called for it. Furthermore, the study is complicated
Speaker 1: by the fact that several plesiosaur species had four limbs
Speaker 1: that were noticeably longer than their rear ones or vice versa.
Speaker 1: Looks like follow up research will have to take species
Speaker 1: specific data into account. Today's episode was written by Mark Mancini,
Speaker 1: produced by Dylan Fagan, and for more on this and
Speaker 1: other topics, please visit us at how stuff works dot com.