Are Cassowaries Dinosaurs Hiding in Plain Sight?

Are dinosaurs still alive today? Jurassic Park is just a movie, but if you’ve ever seen a cassowary’s helmet-like crest or their scaly, clawed feet, you might wonder. Cassowaries may not be dinosaurs, but they are thought to be their closest living relatives. Find out how these birds are related to dinosaurs and discover the cassowary’s incredible dinosaur ancestor.

How Can Birds Be Related to Dinosaurs?

Although some scientists remain unconvinced, most paleontologists recognize that modern birds are descendants of dinosaurs called theropods. Theropods are two-legged dinosaurs that include velociraptors and their terrifying Tyrannosaurus rex cousins. For many years, Archaeopteryx was the only fossil that suggested a link between dinosaurs and birds. Archaeopteryx was a flying dinosaur with feathered wings and lightweight bones like birds. Yet, it had a bony tail, claws, and teeth more like theropod dinosaurs.

While it’s true Archaeopteryx had a mix of avian and reptile attributes, it is clear that bird-like characteristics began to appear in dinosaurs well before the evolution of modern birds. New analyses of the fossil record show that feathers, bipedal locomotion, smaller body sizes, and wings evolved over millions of years. What seems like a huge leap to many of us appears to paleontologists as a predominantly orderly transition from dinosaurs to birds. Recent finds from China have provided even more evidence of this connection.

Cassowaries’ Dinosaur Characteristics

Cassowaries and other ratites, flightless birds like ostriches, emus, and rheas, are believed to be the closest modern birds to dinosaurs. Cassowaries are often considered to be the nearest relative, as they are thought to share more dinosaur-like attributes. They have small heads, but large bodies with long legs. Although they can’t fly, they have small wings. This is similar to the ornithomimidae family of theropod dinosaurs that are thought to bear a superficial resemblance to ostriches.

Cassowaries also walk on two feet like theropod dinosaurs. Their clawed, three-toed feet are similar to the footprints of theropods. For example, Tyrannosaurus rex had three clawed toes that touched the ground. (A fourth toe, called a hallux, was higher up on the foot and did not touch the ground.) Cassowary feet and toes are also covered in scales, or scutes, made of keratin. Many dinosaurs had scales, and some dinosaurs, such as the Psittacosaurus, had both scales and feathers like the cassowary. Yet, how are these features different than other large, flightless birds? Two cassowary characteristics set them apart from the rest: bony, helmet-like crests called casques and long, dagger-like inner claws.

The Cassowary’s Ancient Ancestor

The image shown above portrays a dinosaur species called Corythoraptor jacobsi. A nearly intact skeleton was located in Ganzhou in the Jiangxi Province of southern China. The dinosaur is believed to have lived in the Late Cretaceous era, or about 72 million years ago. Some of its characteristics include a long neck, feathers, a bony crest on its parrot-like head, a toothless beak, powerful legs, and sharp claws. The dinosaur is considered to be morphologically similar to modern cassowaries, referring to the resemblance of its physical characteristics to these living birds.

Scientists who analyzed the skeleton found that the makeup of the skull crest in Corythoraptor jacobsi was very similar to the makeup of the helmet-like casque of the modern cassowary. The interior of both the dinosaur’s and the cassowary’s crests are pneumatized, meaning there are air-filled cavities in the bone, not unlike our sinus cavities. They note that the dinosaur’s crest was about 1/16th of an inch thick and covered in a keratin-like substance. Cassowaries’ crests are around 1/16th to 1/8th of an inch and are also covered in a keratin shell. That this recently discovered dinosaur has such a striking resemblance to modern cassowaries is more evidence showing the evolutionary path from dinosaurs to modern birds.