Many dinosaurs had feathers and behaviors similar to modern birds, leading scientists to believe that birds evolved from theropod dinosaurs. There are a few key dinosaurs that show remarkable bird-like qualities, making them good candidates for being the closest relatives to today’s birds. In this article, we will explore which dinosaur traits and fossils provide the strongest evidence for avian ancestry and which dinosaur is ultimately the most bird-like.
Feathers
One of the most striking bird features that some dinosaurs possessed is feathers. Primitive feathers and feather-like structures have been found preserved with fossils of several theropod dinosaur species over the past few decades.
Some of the most bird-like dinosaurs with feather evidence include:
- Sinosauropteryx – This small carnivore from China exhibited a coat of simple filament-like feathers over its body, arms, and tail.
- Sinosauropteryx – This small carnivore from China exhibited a coat of simple filament-like feathers over its body, arms, and tail.
- Sinosauropteryx – This small carnivore from China exhibited a coat of simple filament-like feathers over its body, arms, and tail.
- Sinosauropteryx – This small carnivore from China exhibited a coat of simple filament-like feathers over its body, arms, and tail.
- Sinosauropteryx – This small carnivore from China exhibited a coat of simple filament-like feathers over its body, arms, and tail.
Primitive feathers help regulate body temperature and may have initially evolved for insulation. More complex, symmetrical feathers first appear in bird-like dinosaurs like Archaeopteryx and are key adaptations for flight. The discovery of any dinosaur species with feathers provides evidence that it is closely related to modern birds.
Hollow Bones
In addition to feathers, birds also have lightweight, hollow bones which aid in flight. Paleontologists have identified several feathered theropod dinosaurs that also share this hollow bone structure, including Archaeopteryx and Microraptor.
Microraptor was a four-winged dinosaur about the size of a hawk that lived 120 million years ago. Analysis of its fossils shows that many of its bones were hollow, just like birds. Hollow bones reinforce the link between dinosaurs like Microraptor and avian species. Having less dense bone mass would have made flight easier for bird-like dinosaurs.
Other Bird-like Traits
Beyond feathers and hollow bones, certain dinosaurs display additional physical traits that resemble modern birds:
- Wishbones – The wishbone or furcula is a unique fused collarbone structure found only in birds and some dinosaurs like Archaeopteryx, Velociraptor, and Deinonychus. It provides structural reinforcement important for flight.
- Nesting behavior – Some fossils provide evidence that various theropods like Oviraptor brooded their eggs in nests as birds do.
- Avian style lungs – Studies of fossilized remains suggest small theropods like Sinosauropteryx had a lung structure similar to birds.
- Grasping hands – Raptors like Deinonychus had hands capable of strongly gripping prey, reminiscent of bird talons.
The combination of wishbones, nesting habits, avian lungs, and raptor-like hands in some dinosaurs demonstrates how much certain theropod behaviors and anatomy converged on that of birds.
Most Bird-like Dinosaur Candidates
When all the evidence is compiled, a few theropods stand out as contenders for the dinosaurs most closely resembling birds:
Archaeopteryx
This small feathered dinosaur from the late Jurassic is considered a transitional link between birds and dinosaurs. Archaeopteryx had asymmetrical flight feathers, a wishbone, clawed hands, and other bird-like traits. But it also retained teeth and a long bony tail, showing its theropod roots. Several beautifully preserved Archaeopteryx fossils have been found that showcase both its dinosaur and avian features clearly.
Microraptor
Microraptor was a tiny four-winged dinosaur with elongate feathers on both its forelimbs and hindlimbs. It is believed to have been capable of gliding or powered flight and would have been very bird-like while airborne. Microraptor lived about 125 million years ago and was one of the earliest known dinosaurs with feathers suited for flight.
Velociraptor
Famous thanks to Jurassic Park, Velociraptor was a feathered carnivore that possessed a wishbone, hollow bones, and a keen intelligence for hunting in packs. Multiple well-preserved Velociraptor fossils have been found curled up brooding nests just as birds do, providing behavioral evidence for its avian nature. Velociraptor and its relatives like Deinonychus had some of the most bird-like brains among dinosaurs.
| Dinosaur | Feathers | Hollow Bones | Wishbone | Nests |
|---|---|---|---|---|
| Archaeopteryx | Yes | Yes | Yes | Yes |
| Microraptor | Yes | Yes | Yes | Yes |
| Velociraptor | Yes | Yes | Yes | Yes |
Conclusion
Based on the evidence, there are several extremely bird-like dinosaur candidates, but the title of most avian dinosaur likely goes to Archaeopteryx or Microraptor. Both had aerodynamic feathers enabling flight capability, hollow bones, clawed hands, wishbones, and other striking anatomical similarities to birds. While other theropods like Velociraptor were also very bird-like in intelligence and behavior, Archaeopteryx and Microraptor physically resembled modern birds the most. Their fossils capture a remarkable evolutionary transition between non-avian dinosaurs and early birds. Birds became the only dinosaur lineage to survive the extinction event 66 million years ago, but these bird-like dinosaurs provide a snapshot into how avian characteristics first emerged through natural selection favoring feathered flight.
