Microraptor – the four-winged dinosaur that ate birds

By ED YONG - DISCOVER MAGAZINE
Added: Tue, 22 Nov 2011 03:01:15 UTC

We now know that birds evolved from small, feathered dinosaurs. It’s easy to think that since birds are still around today, they must have come after their dinosaur cousins, but that’s not true. In the Cretaceous period, dinosaurs were still around while their descendants flitted through the skies. And some dinosaurs made meals of their flighty relatives. Jingmai O’Connor from the Chinese Academy of Sciences has uncovered the remains of a small dinosaur called Microraptor that has the bones of small bird in its gut.

O’Connor analysed the fossil with Xing Xu, a Chinese scientist who has made a career from discovering beautiful feathered dinosaurs. Microraptor is one of his most important finds. This tiny animal, about the size of a pigeon, had four wings, with long feathers on both of its legs as well as its arms. It was, at the very least, a very competent glider, if not a true flier.

The specimen that O’Connor and Xu have studied isn’t the best preserved Microraptoraround. However, it does clearly have the remains of a small bird in its gut, including the left wing and both feet. There aren’t enough bones to tell which species it was, but the distinctive shape of its leg bone singles it out as one of the enantiornithines, an extinct group of early birds. They were, after all, one of the most common groups of birds in the forests of China, where Microraptor hunted.

The bird wasn’t just buried alongside Microraptor, for its bones are enclosed by the larger animal’s ribs. It must have been eaten, and O’Connor thinks that Microraptor probably killed the bird, rather than scavenging one that was already dead. Many of its bones are still found in the right orientation, and the animal facing down towards Microraptor’s hips. The dinosaur probably caught it and swallowed it head-first, just like many modern birds of prey do.