According a study published in Journal of Science, some dinosaurs had the ability of night vision allowing them to hunt at night. Scientists have reached this conclusion by studying the eyes of fossilized dinosaurs and comparing them with the night flying birds.
Velociraptors, one of the dinosaurs in Jurrasic Park movie were also night hunters. Scientists tried to find similar symptoms in T-Rex but not enough fossil record was available. The dinosaurs had to keep their bellies full at night and hence they had to hunt at night too, contrary to the belief held earlier that they hunted only at day while the smaller animals hunted at night to avoid dinosaurs.