Dinosaur Era marine reptiles known as plesiosaurs literally flew through the water, according to new research that found their swimming technique was very similar to that of birds in flight.
The discovery, reported in the journal PLOS Computational Biology, solves a longstanding plesiosaur puzzle over how these now-extinct animals used their unusual, four-flippered body to swim through the ocean.
Sharks vs. Dinosaurs: Deadly Encounters
"Plesiosaur swimming has remained a mystery for almost 200 years, so it was exciting to see the plesiosaur come alive on the computer screen," co-author Adam Smith of the Nottingham Natural History Museum said in a press release.
The "computer screen" refers to computer simulations that he, lead author Shiqlu Liu of the Georgia Institute of Technology and their colleagues created.
Based on fossil finds, the scientists modeled plesiosaurs. They then simulated thousands of different swimming motions to see which ones would have been the most effective, given the plesiosaur's unique body plan.
Video: Dinosaur Sex: How Did That Work?
Surprisingly, flapping the rear flippers did not increase forward speed much.
"Our simulations show that the forelimbs provide the majority of thrust, and that the thrust from the hind limbs is weak," explained the researchers. "The plesiosaur swims primarily with its forelimbs using an underwater flight stroke, essentially the same as turtles and penguins."
Mosasaurs, another group of predatory marine reptiles that is now extinct, also had four flippers. They are featured in the below Discovery production from 2012, which took an educated guess, based on research at the time, on how they moved.