Dinosaurs Shook Their Tail Feathers To Attract Opposite Sex: Study

on January 04 2013 4:51 PM
Oviraptor
Artist's conception of the courtship ritual of oviraptor Ingenia yanshini, depicting a male with a tail-feather fan displaying for an onlooking female. Persons et al./Sydney Mohr

 

Peacocks weren’t the first creatures to shake their tail feathers to try and impress a potential mate. A new study led by a University of Alberta paleontologist finds evidence that certain dinosaurs waved feathery tail fans around to entice the opposite sex.

In a paper published in the journal Acta Palaeontologica Polonica on Fridayresearcher Scott Persons and colleagues from the American Museum of Natural History and the University of Arizona examined the tails of four different kinds of dinosaurs, some of which lived 45 million years apart. He focused on a group of dinosaurs called oviraptors, which lived in the Cretaceous, the last dinosaur age.

“By this time, a variety of dinosaurs used feathers for flight and insulation from the cold,” Persons said in a statement on Friday. “This shows that, by the Late Cretaceous, dinosaurs were doing everything with feathers that modern birds do now.”

Persons found that in some species of oviraptor, the last few vertebrae in the tail were fused into a structure called a pygostyle. The only animals that have pygostyles these days are modern birds.

Though flightless, several oviraptors are thought to be feathered, based on fossil evidence. One early oviraptor species called Similicaudiptery appears to have had a fan of feathers radiating from the tip of its tail.

Some scientists had speculated that oviraptors used their tails in a sculling-type motion for swimming, since they’re so muscular, but Persons doesn’t quite agree. Other research has shown that the back legs of oviraptors were not well-adapted for an aquatic lifestyle, and, at any rate, they tended to live in arid environments anyway.

An alternative explanation that Persons proposes is that oviraptors employed their feather fan-topped tails in a courtship dance.

Based on what we know about an ovitraptor’s musculature, it would have been able to swing and twist its tail “with a degree of muscular dexterity beyond that of most other theropods and modern reptiles,” Persons writes. “Oviraptorosaurs would also have had the muscular control necessary to swiftly strike and hold the tail in desired sinuous or erect poses.”

There’s also some evidence that at least one oviraptor species -- Caudipteryx -- had feathers with bands of contrasting color, which would have made for quite a show. It would certainly be a much different display than any bird we’ve seen, given that the oviraptor’s tail would be prehensile. If Persons’ hypothesis is true, then scientists may eventually find evidence of sexual dimorphism, as in birds, with a flashy male and a comparatively less ostentatious female.

"Between the crested head and feathered-tail shaking, oviraptors had a propensity for visual exhibitionism,” Persons says.