Dinosaurs were some of the largest creatures to ever roam the Earth, but the mystery of how they supported their great weight remains. A new study published in PLOS ONE now indicates that the answer may lie in their unique bone structure, which differs from mammals and birds.
The bone is made up of different layers of different consistency, including the spongy interior, or trabecular. This part of the bone is formed of porous, honeycomb like structures.
A group of inter-disciplinary researchers, including palaeontologists, mechanical engineers, and biomedical engineers, analysed trabecular bone structure in a range of dinosaur samples, ranging from only 23 kg to 8000 kg in body mass. Their study found that the structure of dinosaur bones possessed unique properties allowing them to support large weights.
‘The structure of the trabecular, or spongy bone that forms in the interior of bones we studied is unique within dinosaurs,’ said Tony Fiorillo, palaeontologist and one of the study authors. ‘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.’
Their analysis included scanning the distal femur and proximal tibia bones from dinosaur fossils, and modelling how mechanical behaviour may have occurred. The research team also used allometry scaling – a method of understanding how physical characteristics change with physical size. They then compared the architecture of the bones to scans of both living and extinct large animals, such as Asian elephants and mammoths.
Researchers hope that they can apply their findings to design other lightweight structures such as those used in aerospace, construction, or vehicles.
‘Understanding the mechanics of the trabecular architecture of dinosaurs may help us better understand the design of other lightweight and dense structures,’ said Trevor Aguirre, mechanical engineer and lead author of the paper.