If you ’re quenched with the solvent to which came first , the chicken on the egg , and require a related to puzzle , consider this : did flying creatures rise feathers to aid with something they had already learned to do ? Or did the plumage come first , proving very utilitarian to creature about to take to the sky ?
The reply , it seem , is that the feathers were a display mechanics before they were used to get their owner off the terra firma . As evidence , anArchaeopteryxskeleton has been line up to have leg feather that would be little use for flying .
Although even earlier examples of avian ancestryhave been identified , Archaeopteryx remain our go to author for information on the early evolution of birds .
Christian Foth of Ludwig Maximilians University examined an unco well preserved Archaeopteryx . InNature , Foth and his coauthors describe “ the integral physical structure was covered in pennaceous feather , ” These were 4 - 4.5 cm long on the upper legs but much shorter towards the foot . Meanwhile , the poop feathers were more than twice as prospicient , which would have made them excellent for present off to mate or rivals .
However , the author mention the tail feather were asymmetrical , like those of modern flee skirt whose feathers are shaped so they can bring forth lift just bytilting them . As such they may have allow “ a subaltern aerodynamic routine , ” they say .
On the other hand the leg feathers were symmetrical around the fore , get them of little use in flight . This undercuts thetetrapteryx theory , which project that very early birds had four backstage , using both front and rear limbs to fly . This idea emerged from the reflexion that some bird have recollective feathers on their legs when first hatched . Advocates consider as a form ofatavism . Whether or not hatchling feathers are a throwback to 150 million year old dinosaur antecedent , it seems the sort of feathers those former birds were skylark would have been of more employment in show off to fellow than in taking to the skies .
comparison in the same paper with other plumage - sporting dinosaurs suggest that unlike species found varying employment for their plumage , including insularity and disguise , although display was probably the most common .
“ An analysis of the phyletic distribution of pennaceous feathers on the tail , hind limb and arms of advance maniraptorans and basal avialans powerfully indicates that these structures evolve in a useable context other than flight , most probably in sexual congress to display , ” the authors argue . Only later , were they “ recruited for aerodynamic social occasion . ”
