Some species of dinosaurs were nocturnal and would hunt during night, researchers at the University of California, Davis, claims.

According to the research published Friday in the journal Science, a study of the eye area of fossilized dinosaurs and their comparison with those of the present-day birds and reptiles suggested that small, flesh-eating dinosaurs were nocturnal.

The study also suggests that large, plat-eating dinosaurs were active both during the day as well as night.

Speaking on the findings, evolutionary ecologist Lars Schmitz said, “We thought the mammals were hiding in the dark but now it looks like the hunters were following them there.”

While Velociraptor dinosaurs were likely nocturnal animals, nothing could be determined about Tyrannosausus rex as they are no fossils with sufficiently well-preserved eye areas.

Flying dinosaurs were active only during the day-time.

The study contradicts the generally held believe that most dinosaurs would hunt during the day, while smaller mammals were active during night.