Apart from birds and tree-dwelling mammals, the small flying dinosaur known as Microraptor snacked on fish, state researchers at the University of Alberta.

Based on fossils unearthed from China, the researchers say that these dinosaurs were known to be complete hunters, with the ability to swoop down and pick fish that served as prey.

"We were very fortunate that this Microraptor was found in volcanic ash and its stomach content of fish was easily identified," paleontology graduate student Scott Persons said.

Till date it was believed by a large number of paleontologists that Microraptors, which were the same size as that of modern-day hawks, resided on trees and fed specially on birds and squirrel-sized mammals.

"Now we know that Microraptor operated in varied terrain and had a varied diet," Persons was quoted as saying in Sciencedaily. "It took advantage of a variety of prey in the wet, forested environment that was China during the early Cretaceous period, 120 million years ago."

After carefully analyzing the fossil, researchers noticed that the teeth of Microraptor were adapted to catching slippery wriggling prey, like fish. Unlike most of the meat-eating dinosaurs that had teeth with serrations on both the sides, Microraptors had teeth serrated on just one side, and the rest of its teeth were angled forward.

According to Persons, Microraptors pierced fish on their teeth. The prey wouldn't tear apart as it struggled to escape due to the presence of single serrations. After piercing through the fish, all it did was raise its head back and the fish would slide off the teeth and would be swallowed as whole.

Talking about the configuration of Microraptor's wing, the researchers compare it with a bi-plane. It was capable of short controlled flights since it had long feathers on the forearms, hind legs and tail that made it easy.

This fossil was the first evidence of a flying raptor that snacked on fish.