Dinosaurs that lived 200 million years ago may have used three toes to walk through mud just like modern-day guinea fowls, study shows
- Scientists compared guinea fowl tracks to those of meat-eating theropods
- Similarities suggested dinosaurs also moved in a looping motion with their legs
- Researchers said the motion had lasted 200 million years due to advantages
Dinosaurs that lived 200 million years ago may have walked using their three toes to cut through mud just like the game bird guinea fowl does today.
Scientists made the find after comparing tracks made by the birds to imprints left in rocks by meat-eating theropods, a group that eventually gave rise to Tyrannosaurus rex, that roamed through moder-day Connecticut during the Early Jurassic period.
The dinosaur footprints showed ‘similar movement’ to the birds, suggesting they also moved in a looping motion, used their claws to create entry and exit paths in the soil, and also collapsed and opened their feet in the same way.
Researchers said the motion may have survived so long because of its ability to ‘provide a stable base when spread, yet collapse to facilitate extraction from deformable substrates’.
Pictured above are the fossil footprints that were used in the study. They were created in the Early Jurassic by small meat-eating theropod dinosaurs ranging in modern-day Connecticut
In the study, published in Biology Letters, three guinea fowl walked through mud that was either solid, dry, firm or semi-liquid, before researchers took X-rays of their tracks. Their movements were also recorded by two cameras.
The images created were then used to model three-dimensional toe coordination in the birds, and animated to show their movements.
Guinea fowls were chosen for the study because their three-toed feet ‘closely resemble those of bipedal, non-avian dinosaurs, allowing the visible movements responsible for shallow tracks to be studied directly,’ according to the researchers.
Measurements were also taken from the fossils, housed in the Museum of Natural History at Amherst College.
Study author Dr Peter Falkingham, senior lecturer in vertebrate biology at Liverpool John Moores University, said: ‘Dinosaurs were moving in a very similar way to modern birds even 200 million years ago, many millions of years before birds evolved, even though they were quite different.
The results suggest that dinosaurs similar to coelophysis, pictured, may have walked just like guinea fowls. The researchers said this showed the evolutionary advantage of the movement
Dinosaurs similar to Dilophosaurus, also pictured, may also have walked like guinea fowl
‘The similarity of motion, and the similarity of foot shape, between dinosaurs and birds today tells us how successful and versatile that foot has been evolutionarily.’
He pointed out that dinosaurs had long, muscular tails, while birds do not.
Guinea fowl have also been used in a study on dinosaurs in 2014, where researchers filmed them walking through poppy seeds to understand how dinosaur tracks are made.
The tracks were also x-rayed, to provide clues on how the footprints were made. The study was published in Proceedings of the National Academy of Sciences.
The Connecticut fossil tracks contain footprints from dinosaurs related to coelophysis and dilophosaurus.
What is the relationship between dinosaurs and birds?
Archaeopteryx in flight, pictured
Humble pigeons, clucking chickens and gobbling turkeys are all descendants of dinosaurs, scientists have learned.
The gradual evolution of birds from meat-eating theropods is thought to have begun about 160 million years ago, possibly as some smaller theropods moved into trees to search for either food or protection.
The discovery of a feathered Compsognathus in China in 1996, that lived during the Early Cretaceous, was the first indication that dinosaurs may have had feathers.
Another relative, Archaeopteryx, had been found a century earlier but was quickly classed as the first bird – due to the feathers covering its body.
But scientists re-assessed this analysis, and others. This also led to modern re-interpretations of dinosaurs, suggesting that many theropods may have had feathers.
Birds were the only dinosaurs to survive an asteroid hitting the Earth, possibly favoured by their small size, and later went on to colonise the globe.