Dinosaur daddies took care of their young alone

In 1995, a palaeontologist called Mark Norrell reported an amazing discovery - the fossilised remains of a dinosaur called Troodon, sitting on top of a large clutch of eggs. The fossil was so well-preserved and its posture so unmistakeable that it provided strong proof that some dinosaurs incubated their eggs just as modern birds do. And since then, two other small predatory species - Oviraptor and Citipati - have been found in brooding positions on top of egg clutches.