Biomechanics
How did Dinosaurs Really Move?
Today, the scientific field of biomechanics is making great headway providing answers to these questions. Experts examine fossils then compare their findings with the principles of physics and engineering revealed by studying the biological movement and musculature of animals. As a result, they are able to piece together a highly accurate sense of motion, which when combined with computers can bring scientifically accurate representations of Dinosaur movement to life.
:: Learn more about sauropod biomechanics at AMNH ::
Vertebrates have similar muscle tissue
One thing scientists know is all vertebrates have a common ancestor, because they all have similar muscle tissue; under a microscope, it's difficult to tell the muscle of a crocodile from that of a mouse or an elephant. As a result of these similarities, scientists think that the muscles of living animals hold clues to the muscles of dinosaurs.
How fast did Tyrannosaurus rex really run?
© 2005 AMNH
Their results? A sprinting T. rex was a physical impossibility. While a small theropod could run fairly quickly, a six-ton tyrannosaur would have required about three tons of leg muscle to reach speeds of 70 kilometers (45 miles) per hour!
An old-fashioned barnyard chicken is fairly fast. Like any animal, it owes its speed partly to muscle anatomy. The muscles in each leg represent up to 10 percent of a chicken’s body weight. In fact, chickens are overbuilt for speed: an animal of a chicken's weight and shape could run fast with only half that amount of leg muscle.
The scientists who created the computer model of T. rex decided to enlarge a speedy chicken to T. rex's size while keeping its design the same, a process called scaling up. The result? A 6,000 kilogram (13,000-pound) chicken would need fantastically muscular legs just to walk. Instead of 10 percent, a running mega-fowl would need 62 percent of its body weight as muscle in each huge limb, which is a mathematical and biological impossibility.
:: Learn more about theropod biomechanics at AMNH ::
Bigger Animals Run with Straight Legs
From AMNH video © 2005
Elephants and rhinos walk with straighter legs than small, fast animals do, because it conserves energy.
Attaining a weight of 1,000 kilograms (2,200 pounds) was an important milestone in the life of a young tyrannosaur. Below that weight, the animal could move fairly fast; above it, life shifted into the slow lane.
Fast running would have been useful to a juvenile dinosaur. The young are more vulnerable to predators than are their full-grown parents; speed might have helped to offset the risks of small size.
Elephants are capable of their fastest speeds at about age two. Still relatively small at that age, they are vulnerable to predators, so speed may provide a slight advantage.
:: Learn more about dinosaur biomechanics at AMNH ::
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