Exceptionally well-preserved dinosaur feathers are prompting scientists to reconsider how some dinosaurs truly looked—and raising the possibility that certain species were far fluffier than previously imagined.
Researchers at the University of Bristol examined fossilized feathers from Anchiornis, a small, bird-like dinosaur roughly the size of a raven. This animal had a wingspan of up to 0.5 meters (1.64 feet), measured about 0.4 meters (1.3 feet) in length, and weighed between 0.1 and 0.25 kilograms.
The team discovered a feather structure unlike that seen in earlier fossils. The extinct feather type consisted of a short quill with long, flexible barbs branching out at shallow angles. These barbs formed two vanes and created a distinctive forked appearance. Compared with the sleek, aerodynamic feathers of modern birds, these primitive feathers were much softer and fluffier.
Anchiornis also possessed four wings, with feathers not only on its forelimbs but also on its hind legs. Combined with its unusual feather structure, this likely gave the dinosaur a shaggy, almost downy appearance—far removed from the streamlined silhouettes often associated with modern flying birds.
According to the researchers, this dense and fluffy plumage may have influenced both the dinosaur’s physiology and its flight capabilities. The extra feathering could have made temperature regulation more challenging and may have increased air resistance, potentially reducing aerodynamic efficiency when gliding.
Based on their findings, the team reconstructed a new visual interpretation of Anchiornis—one that differs significantly from traditional dinosaur depictions.
Illustrator Rebecca Gelernter collaborated with Evan Saitta and Jakob Vinther from the University of Bristol’s Schools of Earth Sciences and Biological Sciences to produce a life reconstruction of the animal. The coloration was inferred from pigment structures preserved in the fossils, though such reconstructions remain debated within paleontology due to inherent uncertainties.
“The novel aspects of the wing and contour feathers, as well as fully-feathered hands and feet, are added to the depiction,
Most provocatively, Anchiornis is presented in this artwork climbing in the manner of hoatzin chicks, the only living bird whose juveniles retain a relic of their dinosaurian past, a functional claw. This contrasts [with] much previous art that places paravians perched on top of branches like modern birds.
However, such perching is unlikely given the lack of a reversed toe as in modern perching birds and climbing is consistent with the well-developed arms and claws in paravians.
Overall, our study provides some new insight into the appearance of dinosaurs, their behavior and physiology, and the evolution of feathers, birds, and powered flight.”
— Evan Saitta, co-author of the study.
Rather than perching like modern birds, the new reconstruction depicts Anchiornis climbing tree trunks—similar to young hoatzins, which retain clawed wings during early life. This behavioral interpretation aligns more closely with the anatomy of paravian dinosaurs, which lacked the reversed toe typical of today’s perching birds but had well-developed arms and claws suited for climbing.
The findings offer fresh insights into dinosaur appearance, behavior, and the evolutionary steps that eventually led to modern birds and powered flight.
The research was published in the journal Palaeontology.
Reference:
Saitta et al., Additional information on the primitive contour and wing feathering of paravian dinosaurs, published in Palaeontology, 28 November 2017.