Maybe you’ve realized that there are more and more pictures or movies where you can see dinosaurs covered with small feathers. Why did those artist do that? Are there profound fossils or other data which support that idea?
There are fossils which show feathers on dinosaurs. The earliest are dated at the Early Cretaceous (some 124 million years ago). It is important to add at this point that we cannot expect too much fossil founds with feathers in the future because there had to be a number of lucky circumstances in the past came together to preserve feather structures. Those circumstance must have been, for example, hot vulcano ashes. A blog fellow made this picutre at a Natural History Museum in Vienna:
He stated that it looks quite trashy and that the artists used feathers of emus or ostriches to cover the dinosaur. But these artist are not as wrong as it looked on the first sight. Ostriches, for example, have no feathers for flying as dinosarus had have, too. Today, scientists do not really know which type of feathers or fibres dinosaurs had. This demands further investigations. Meanwhile some are pretty sure that the fossils shows down-feathers which are similar to birds. Wiki states:
Despite doubts the fossil feathers have roughly the same appearance as those of birds fossilized in the same locality, so there is no serious reason to think they are of different nature; moreover, no non-theropod fossil from the same site shows such an artifact, but sometimes show unambiguous hair (some mammals) or scales (some reptiles).
— ‘Feathered Dinosarus, Fossil evidence’ / Wikipedia, the free encyclopedia
A big questions is the advantage of therapoda to have feathers. One is temperature isolation which helps mainly younger or smaller dinosaurs to regulate their heat in a desert environment. An other very plausible explanation is courtship. But now I want to show you how those ‘feathers’ look on a fossil. Therer are nice pictures on the website of the ‘American Museum of Natural History’. When you look on the detailed picutre it is not very hard to realize the feather strucutres. More data you can find on http://research.amnh.org/vertpaleo/dinobird.html
This example is only one of many but there aren’t enough fossils to determine which dinsaurs had feathers and which not. But it is possible to determine it without profound fossil documentation. Paleontologist use in such cases the cladistic analysis. They build ‘cladistic trees’ or ‘cladograms’ to order all life forms. An analysis on feathered dinosaurs allows to state that even the gigantic Tyrannosaurs had feathers but only in ‘an early stage after hatching’. Wiki states concerning this issue:
In particular, the smaller theropod species may all have had feathers and possibly even the larger theropods (for instance T. rex) may have had feathers, in their early stages of development after hatching. Whereas these smaller animals may have benefitted from the insulation of feathers, large adult theropods are unlikely to have had feathers, since inertial heat retention would likely be sufficient to manage heat. Retention of internal heat may even have become a problem, had these very large creatures been feathered.
Fossil feather impressions are extremely rare; therefore only a few feathered dinosaurs have been identified so far. However, through a process called phylogenetic bracketing, scientists can infer the presence of feathers on poorly-preserved specimens. All fossil feather specimens have been found to show certain similarities. Due to these similarities and through developmental research almost all scientists agree that feathers could only have evolved once in dinosaurs. Feathers would then have been passed down to all later, more derived species (although it is possible that some lineages lost feathers secondarily).
— Feathered Dinosaurs, Taxonomy and the inference of feathers in other dinosaurs / Wikipedia, the free encyclopedia
When you want to read more of this stuff check out the ‘Journal of Dinosaur Paleontology’.
