JOHANNESBURG, South Africa — A new study about prehistoric life may change a lot about how we think of dinosaurs. While the first image that comes to mind is likely of a giant reptile rampaging through a sunny forest, researchers have discovered one predator which looks more like a chicken and did its hunting at night.
A team from the University of the Witwatersrand adds this three-foot-tall winged reptile had “Roadrunner-style” legs and enormous eyes. Its extraordinary vision and owl-like hearing enabled it to spot and catch prey “in complete darkness.”
The study finds the sprightly Shuvuuia deserti was also blessed with brawny “weightlifter arms” and a single claw on each hand. It would have rapidly run down small mammals and insects after sunset, using its strong forelimbs to pry them from burrows or shrubs. Shuvuuia deserti also had a fragile, bird-like skull which puts it among the most bizarre of all dinosaurs discovered to date.
Researchers believe this strange species lived around 80 million years ago during the Late Cretaceous period in what is now Mongolia. At the time, the Gobi Desert still had a dry and seasonal climate, ranging from warm summers to bitter winters.
“Nocturnal activity, digging ability, and long hind limbs are all features of animals that live in deserts today,” says study leader Professor Jonah Choiniere in a media release. “But it’s surprising to see them all combined in a single dinosaur species that lived more than 65 million years ago.”
Chickens in the T-Rex family?
Despite their many differences, Shuvuuia deserti were members of the meat-eating theropods, a group which includes the dreaded T-Rex. Researchers add the thousands of species of birds today likely evolved from these creatures.
Although birds live in virtually every habitat on Earth, only a handful still hunt for prey in the dark of night. Scientists have long wondered if their dinosaur ancestors had similar sensory skills.
An international team used CT scanning to analyze the eye and inner ear size of nearly 100 living bird and extinct dinosaur species. They measured the length of an organ called the lagena that processes incoming sound (called the cochlea in mammals).
‘Couldn’t believe what I was seeing’
Results reveal the Shuvuuia’s lagena was almost identical in relative size to today’s barn owl, which has the proportionally longest sound-processing organ of any bird. The findings point to Shuvuuia hunting in pitch black conditions using only its hearing, just like the owl.
“As I was digitally reconstructing the Shuvuuia skull, I couldn’t believe the lagena size,” joint first author Dr. James Neenan from the University of Oxford says. “I called Prof. Choiniere to have a look. We both thought it might be a mistake, so I processed the other ear – only then did we realize what a cool discovery we had on our hands!”
“I couldn’t believe what I was seeing when I got there – dinosaur ears weren’t supposed to look like that!” Prof. Choiniere adds.
How did these creatures hunt in the dark?
The researchers also looked at the scleral ring, a series of bones surrounding the pupil. Like a camera lens, the larger it can open the more light can let in. This enables an animal to have better vision at night.
By measuring the diameter of the ring, the scientists could tell how much light a dinosaur’s eye could gather. The study showed many carnivorous theropods such as the Tyrannosaurus and Dromaeosaurus had vision optimized for the daytime. They had better-than-average hearing too, presumably to help them hunt.
However the Shuvuuia, which belonged to a group called Alvarezsaurs, had incredible hearing and night vision. In fact, researchers say the Shuvuuia had some of the largest pupils yet measured in birds or dinosaurs. This odd combination of features has baffled scientists since the animal’s discovery in the 1990s.
The study, appearing in the journal Science, adds the Shuvuuia’s tendency to forage at night is just like today’s desert wildlife.
SWNS writer Mark Waghorn contributed to this report.