- "Because we're actively manipulating and mutating the animals' genes, adding frog, bird and reptile DNA, we create what is known as 'Null Allele'. The dinosaurs cannot live without something added to their code so for now we're stuck with scales."
- —Henry Wu discussing his failure to recreate feathers(src)
Feathers are a type of keratinous structure found in a vast number of dinosaur species, namely many varieties of Theropod and essentially every family of Coelurosauria. All modern dinosaurs (i.e. birds) have them, and they serve a wide variety of functions from insulation, defense, display, nesting, swimming, and flight. In this respect feathered dinosaurs were little different. However because of the evolving nature of Paleontological discoveries and understanding, feathers have had a fickle relationship with the dinosaurs of InGen.
History of Understanding
For the longest time including the origins of Paleontology and modern Zoology in the 1800s, feathers were thought to be strictly a trait of birds and evolved in a context meant to facilitate flight. Early research into the origins of birds speculated that feathers evolved directly from elongated scales to serve as airfoils so primitive ancestors of birds might glide or parachute from tree to tree. The vagueness into the origin of feathers wasn't helped by the oldest known bird, Archaeopteryx, having near-modern plumed feathers and was clearly capable of some degree of powered flight; meaning the bird predecessor was still unknown. Because 18th and 19th century research chiefly believed dinosaurs were slow moving, cold blooded, and most importantly, strictly ground based animals; it was supposed by researcher Gerhard Heilmann in the 1910s that birds and dinosaurs were related but the former was not a member of the latter's group. Heilmann's research was extensive, but he was working with an very sparse fossil record and tried to made do with what was known as well as studying bird embryonic development. He came very close to concluding birds were a type of Theropod dinosaur, but ultimately decided against it. Still his work was so pervasive and influential that many aristocratic Paleontologists and Ornithologists considered the issue of bird origins solved even though this assertion was frequently challenged by many . Some Paleontologists as far back as a half century prior still contended that birds were living members of Dinosauria, with Thomas Huxley insisting early on in the 1800s that dinosaurs were warm-blooded ancestors of birds and might have had feathers. Others like Dr. Edward Cope and Barnum Brown supported Huxley's arguments by demonstrating the legs of Theropod dinosaurs and birds are virtually indistinguishable from each other. Part of Heilmann's assertion was based on the observation no dinosaurs were found with a furcula (the "wishbone" made of fused clavicle bones), whereas more basal Archosaurs like crocodilians had unfused or semi-fused clavicles that could have preceded the furcula. He couldn't understand how the clavicles could be present in basal Archosaurs, lost in dinosaurs, and then not only return, but fuse in birds. The problem is the furcula is a very fragile bone that rarely fossilizes, and when it does, it's often warped and easily mistaken for another type of bone.
Huxley and his colleagues view began to get vindicated in the 1960s with the simultaneous discovery of Deinonychus and a new species of Coelophysis, both animals having extremely bird-like bodies that were clearly indicative of an active life style. Deinonychus in particular was demonstrated by it's discoverer, Dr. John Ostrom, to have a skeleton almost identical to Archaeopteryx. Still, very early skin impressions of distantly related dinosaurs had been discovered showing only scales, so it was initially thought these two new genera were no different.
In 1975, Coelophysis became the first non-avian dinosaur depicted with feathers by artist Sarah B. Landry. While speculative at the time, the existence of feathers as far back as the Triassic has been confirmed with newer studies. By the early 1980s, it soon became commonplace to speculate at least a few small and medium sized dinosaurs had some degree of feathers, as some means of insulation is needed for a warm blooded metabolism below a certain mass. This feathering speculation directly tied into a growing consensus after Ostrom and others revived Huxley's theory, stating that birds were a type of surviving Coelurosaurian Theropod. This would mean if any dinosaurs were indeed discovered to have feathers, it would show feathers were not purely an avian characteristic and that birds did indeed evolve from non-avian dinosaurs. Additionally, Heilmann's argument was weakened when indisputable dinosaur fercula bones had been discovered or rediscovered in numberous genera, namely Theropods.
By the late 1980s it was widely speculated some non-avian dinosaurs had feathers, leading to many artists like Otter Zell and Gregory S. Paul to depict Dromaeosaurids (i.e. "Raptors") in particular as feathered in works such as Paul's "Predatory Dinosaurs of the World", which Michael Crichton used for research when penning the novel "Jurassic Park". Crichton, however, did not ultimately incorporate feathered dinosaurs into the novel. These speculations became further vindicated when both new discoveries and previously overlooked finds revealed a vast array of dinosaurs sporting feathers of various types, starting in 1987 with the discovery that Avimimus had a ridge on its arm bones that was interpreted by its discoverer, Dr. Sergei Kurzanov, as anchor points for feather attachment. He even speculated the animal might have been capable of some weak flight; something that while now deemed unlikely for Avimimus, is plausible for other genera discovered since such as Microraptor. This coupled with embryological studies on how feathers develop in modern birds revealed that plumage started as a means of insulation before evolving into other uses, such as the airfoils seen in birds and Dromaeosaurids. By the 2010s, the number of positively identified feathered genera exponentially expanded, aided by the more worldwide knowledge of many fossil fields in northern China which had fine grain sediments necessary to preserve feathers. The decade also included the first soft tissue preservation of dinosaur feathers, when a piece of 100 million year old Burmese amber had a small dinosaur tail preserved in it.
Presence in Taxa
Feathers have been positively identified in dozens of dinosaur species from across multiple families. Additionally, because such traits as integument are present throughout entire families of animals in the modern world, there is no reason to doubt that if one species had feathers; so too would its relation even if they haven't had such evidence preserved. For example, Velociraptor certainly had feathers even though the kinds of rocks it was fossilized in didn't preserve them, and this can be determined because not only are traces of the wings preserved on the animal's bones via notches to fit the feather stems in, but because it has had very close relatives discovered with their feathers intact. Feathers are so common in some families, that an occurance like a scaly Dromaeosaurid lacking feathers would be about as likely as discovering a scaly feline lacking fur. While many dinosaurs did have scales over a majority of their bodies, the presence of feathers in both major categories of dinosaur (Ornithischia and Saurischia) means any dinosaur might have some degree of feathers. The only group known to have plumed feathers like their living representatives, birds, are Coelurosauria theropods. The amount could vary in certain genera within a family just like how the amount of fur can vary in mammals from a complete coat in a deer to a sparsity of hair in whales, usually on account of body size. For example, while all Dromaeosaurs were completely covered save for the tips of the snout and feet; Tyrannosaurs could vary with the wolf sized Guanlong having a full coat, but the elephant sized Tyrannosaurus rex likely having much fewer.
Jurassic Park media
The Jurassic Park novel and Jurassic Park film came out at a time when feathers were largely seen as speculative for non-avian dinosaurs, as serious opposition to the connection between birds and dinosaurs still had some support academically and wasn't widely known to the public, even if the dinosaur origin of birds it had become widely accepted by Paleontologists and Ornithologists to the point it was used by Crichton. While early designs for the first movie did incorporate some amount of feathers, these were dropped into for the sake of consistency with the books, the comparative ease of animating smooth, scaly bodies vs. plumage in early 1990s CGI, and desires by the film makers. Animals with early designs sporting at least some feathers include the Velociraptors and Tyrannosaurus rex.
It was only by the time of The Lost World (novel) and The Lost World: Jurassic Park (film) that feathers on non-avian dinosaurs were proven as a fact. The second Crichton novel also had the first instance of feathered dinosaurs in the main series, with the infant Tyrannosaurus rex having a ring of downy feathers around their necks and torso; something that didn't translate to the film adaptation.
Jurassic Park III was the first movie in the to depict feathers on the dinosaurs in any capacity, with the male Velociraptors having a line of feather quills on the tops of their heads. This was inaccurate at the time, as more complete coats of feathers were already known, but was likely limited to both appeal to audience expectations and reduce the strain on the special effects crews having to come up with entirely new designs. This was especially a problem given the third installment's infamously chaotic development cycle.
For Jurassic World, the step taken in the prior film was reversed; as first indicated when Colin Trevorrow revealed no feathered dinosaurs would be appearing in the fourth installment. This appealed to many fans of the first film especially, who voiced their nostalgia for the 1980s and 1990s depictions of non-avian dinosaurs, and was intended as such to help safeguard the franchise's success after over a decade of theatrical dormancy since the third installment in 2001; but this move angered many Paleontologists. The 2000s and early 2010s had greatly magnified the knowledge of feathered dinosaurs, which had begun appearing prominently in documentaries as early as 2001's "When Dinosaurs Roamed America". The fourth film did acknowledge that its dinosaurs weren't accurate anymore with lines by B. D. Wong's character Henry Wu stating the gene splicing distorted the creatures of the park's appearance into making them look like what the in-universe (and presumably real life) audience wanted them to be. This was explained mostly by the amphibian and reptile DNA used to patch up the genomes of the animals blocking the feather producing genes for the genera whom would have had plumage, and the viral marketing included a piece by Dr. Wu expressing frustration he couldn't get the feathers to be produced. However, detractors pointed out this truth is lost on the general audience as they have no accurate pictures of feathered dinosaurs on screen to compare the park creatures to, and that the high profile nature of the franchise's films, which often see their designs replicated by other media, means the general public believes its depictions to be true to life and express confusion that this isn't the case. Many paleontologists, museum designers, and educators have expressed the reality that the general audience is still largely ignorant that many dinosaurs had feathers even when educating about feathered genera known for decades by the 2020s; said audience often naming the Jurassic Park/World series as a direct reason for their confusion.
The Jurassic World trilogy isn't entirely featherless, but the plumage is greatly restricted and subdued. The hybrid Indominus rex and Indoraptor both have head quills similar to the third installment's male raptors, and a statue of Mononykus with appears in a museum in Jurassic World: Fallen Kingdom with quills on the arms and tail. However, feathered dinosaurs are set to appear in some capacity in Jurassic World: Dominion, with Collin Trevorrow and Paleontology consultant Dr. Stephen Brusatte noting the sixth entry in the film series will take strides to present more updated dinosaur designs while preserving the classic genera's iconic looks.
Feathers have appeared far more prominently in the expanded media for the franchise, likely helped by desires by designers to add variety or not being limited by executive decisions or audience expectations. An early instance was in the Topps comics Return to Jurassic Park V, in which a genetically altered Avimimus appeared sporting a coat of feathers.
- Crichton, Michael (1995) "The Lost World", page 268
- Colin Trevorrow Twitter (2013) https://twitter.com/colintrevorrow/status/314384734190985217?lang=en
- New Scientist article (2013) https://www.newscientist.com/article/mg21829113-700-stars-of-jurassic-park-to-remain-featherless/
- Weisberger, Mindy (2018) https://www.livescience.com/62904-jurassic-world-fallen-kingdom-science.html