Credit: Sydney Mohr
Some dinosaurs danced and literally shook their tail
feathers to attract potential mates, researchers say.
It's long been theorized that at least some feathered
dinosaurs used their plumage for courtship. A new study, published in the journal
Acta Palaeontologica Polonica, strengthens that belief.
The dancing, prancing dinosaurs were oviraptors — two legged,
plant-eating dinos, related to T. rex, that roamed parts of China, Mongolia and Alberta during the
Cretaceous period, which was the final age of the dinosaur.
"Oviraptors clearly had the anatomy needed to sinuously
swish and to gracefully flaunt their tails," lead author Scott Persons told
Discovery News, adding that many of these dinosaurs also had arm fans and head
crests, which could have been part of such eye-catching moments.
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"I suspect that a displaying oviraptor would be quite a
sight, but the precise choreography of a dinosaur mating dance is the sort of
thing that you can't learn from bones and is, sadly, the sort of thing that
paleontologists will probably never know."
Persons, a researcher at the University of Alberta, and his
team, however, were able to tell a lot about the dinosaurs’ appearance and
behavior based on fossil evidence.
The scientists noticed that individual vertebrae at the base
of an early oviraptor Similicaudiptery
and related species were short and numerous, indicating great flexibility.
Based on dissections of modern reptile and bird tales, a reconstruction of the
dinosaur’s tail muscles revealed oviraptors had what it took to really shake
their tail feathers.
Large muscles would have
extended far down the tail, having a sufficient number of broad connection
points to propel the dinosaur's tail feathers vigorously from side to side and
up and down.
Modern-day peacocks and turkeys use their tail plumage in a
similar way. It's possible that some oviraptor feathers were as beautiful and
striking as those of peacocks.
"Exceptional fossils of oviraptors from China, which were
preserved in fine volcanic ash, show definitively that at least some of the
tail feathers had bands of contrasting color," Persons explained. "They may
have had iridescent feathers, like a peacock, but that is a harder question,
and one without definitive evidence."
As for today's birds that use tail plumage to attract mates,
the researchers suspect males did most of the feather flaunting and displaying.
While the timeline for feather evolution is still somewhat
of a mystery, the new findings provide intriguing clues.
Oviraptors with tail feather fans date back to over 120
million years, but Persons said that "they already have well developed
feathers, so I doubt that they were the first."
He thinks dinosaur feathers initially evolved for
insulation, with flight and courtship uses following later. It's even possible
that insulating feathers first evolved in the reptilian ancestors of dinosaurs.
"The oldest fossil feathers are nearly 160 million years
old, but feathers must have evolved many millions of years before that," he
Thomas Holtz, Jr., a vertebrate paleontologist from the
University of Maryland, said oviraptors "are not flightworthy animals, but are
demonstrably feathered. And indeed, the big arm fans and tail fans show that these
feathers are more than just insulation, so display is a very likely use."
The combination of features of these dinosaurs, he continued, reveal they could "flex, fold, and otherwise show off their tail fans in a variety of poses and
movements: hallmarks of a structure used in some form of visual display."