#1
New theory for why some dinosaurs stood on two feet
THE CANADIAN PRESS
First posted: Friday, March 03, 2017 03:28 PM EST | Updated: Friday, March 03, 2017 08:10 PM EST
EDMONTON — Paleontologists at the University of Alberta have a new theory for why some dinosaurs stood on two feet instead of four.
The researchers found clues in the tails of the ancient creatures’ much smaller ancestors, proto-dinosaurs.
Lead author Scott Persons says the tails of proto-dinosaurs had big, leg-powering muscles.
Eventually, the ancient creatures evolved to run faster and for longer distances.
Meanwhile, smaller forelimbs helped reduce their body weight and improved balance, so some proto-dinosaurs gave up walking on all fours entirely.
Persons says earlier theories that proto-dinosaurs stood on two legs just so they could use their forelimbs to catch prey don’t stand up.
A skeleton of the proto-dinosaur Marasuchus, is shown in this undated handout photo. The proto-dinosaur Marasuchus is a squirrel-sized carnivore that likely walked on all fours but ran on two legs. THE CANADIAN PRESS/HO, Scott Persons, University of Alberta

New theory for why some dinosaurs stood on two feet | Canada | News | Toronto Su