Friday, October 26, 2012

Hey Good Lookin': Dinos May Have Used Feathers For Show

Male peacock displaying his mating feathers. Image credit: Jim Corwin photography
In the avian world, feathers make the man (er, males). 
Feathers 'shape' a bird's wings to make them more aerodynamic; they insulate the bird from the cold and can help keep them dry; they can be an indicator of health and provide camouflage but most importantly, flashy feathers often make a bird seem more attractive as a mate. Among many species, males display their plumage to attract females in courtship rituals that aim to convince the female of interest that they would make a good mate. In some cases the roles are reversed, with females seeking to attract males by showing off their plumage. 

Now, believe it or not, this now-extinct terror:

Image credit: National Geographic

is most closely related to this modern day animal:

Image credit: Wikipedia

Yup. Our feathered friends originally descended from dinosaurs, making birds the closest living relative of the Dinosauria. Interestingly, new research suggests that the utility of plumage as a mating device was not lost on some dinosaur species.

Paleontologist Darla Zelenitsky was at first puzzled by the strange markings on the forearms of ornithomimus remains. Ornithimimus literally translates to 'bird mimic', as a living ornithomimid most likely resembled a 400 pound ostrich. Zelenitsky eventually realized that what she was seeing were the remains of feathers. Researchers concluded that flying was out of the question, as the birds were prohibitively large, but it was possible that the feathers were used to keep themselves or their eggs warm.

Zelenitsky then noticed that the feather markings on juveniles suggested a thin, downy coat of feathers, while adults had larger and showier feathers and quills. This suggested that once the dinosaurs had reached reproductive age, their feathers were transformed into something more elaborate to attract potential mates. Researchers later found evidence that the feathers may have been brightly colored and richly pigmented, supporting the hypothesis that the dinosaurs' plumage may have been used to attract the attention of mates in courtship displays similar to those observed among modern day birds.

Artistic rendering of adult and juvenile ornithomimid dinosaurs. Image credit: NPR

These findings put a new twist on the evolutionary origins of feathers, indicating that their added utility as a courtship device may have spurred the evolutionary diversification of plumage. Just like every girl is crazy about a sharp-dressed man, seems like female ornithomimus just couldn't resist well-feathered males. 

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