New Study Helps Explain How Dinosaur Skeletons Supported Massive Loads

Saturday, August 22, 2020

Life reconstruction of Kamuysaurus japonicus, a species of hadrosaurid (duck-billed) dinosaur that lived some 72 million years ago (Cretaceous period) in what is now Japan. Image credit: Kobayashi et al, doi: 10.1038/s41598-019-48607-1.

A team of paleontologists and mechanical and biomedical engineers has compared CT scans of the fossilized bones of hadrosaurs and other dinosaurs with bones of extinct and living mammals and found that the dinosaur trabecular bone architecture was uniquely capable of supporting large weights (up to 47,000 kg) and different than that of mammals and birds.

The largest terrestrial dinosaurs were enormous creatures whose body mass placed massive gravitational loads on their skeleton.

Previous studies investigated dinosaurian bone strength and biomechanics, but the relationships between their trabecular bone architecture and mechanical behavior had not been studied until now.

“The structure of the trabecula, or spongy bone that forms in the interior of bones we studied is unique within dinosaurs,” said study co-author Dr. Tony Fiorillo, a paleontologist in the Huffington Department of Earth Sciences at Southern Methodist University.

“The trabecular bone tissue surrounds the tiny spaces or holes in the interior part of the bone such as what you might see in a ham or steak bone.”

“Unlike in mammals and birds, the trabecular bone does not increase in thickness as the body size of dinosaurs increase. Instead it increases in density of the occurrence of spongy bone.”

“Without this weight-saving adaptation, the skeletal structure needed to support the hadrosaurs would be so heavy, the dinosaurs would have had great difficulty moving.”

Dr. Fiorillo and colleagues used engineering failure theories and allometry scaling to analyze CT scans of the distal femur and proximal tibia of several dinosaur species: a troodontid, a caenagnathid, an ornithomimid, a therizinosaur, and two hadrosaurs (Edmontosaurus annectens and Edmontosaurus regalis).

“Our team is the first to use these tools to better understand the bone structure of extinct species and the first to assess the relationship between bone architecture and movement in dinosaurs,” they said.

The researchers then compared their findings to scans to extinct and living mammals, such as the Java mouse deer, the domestic sheep, the Siberian tiger, the white rhinoceros, the Asian elephant and the Columbian mammoth.

“Understanding the mechanics of the trabecular architecture of dinosaurs may help us better understand the design of other light-weight and dense structures,” said study lead author Dr. Trevor Aguirre, a researcher in the Mechanical Engineering Department at Colorado State University.

The findings were published in the journal PLoS ONE.


T.G. Aguirre et al. 2020. Differing trabecular bone architecture in dinosaurs and mammals contribute to stiffness and limits on bone strain. PLoS ONE 15 (8): e0237042; doi: 10.1371/journal.pone.0237042