There’s no longer really any doubt that birds are a type of dinosaur. These days, the debate is about details. The strong evidence doesn’t just come from fossilised bones and similarities found across the skeleton, but from fossilised soft tissue – especially feathers. Many dinosaurs had not just some kind of body covering, but distinctive bird-like feathers. Rare fossils also give us glimpses of the behaviour of bird-like dinosaurs, such as Mei long, a small, duck-sized bipedal dinosaur from the Cretaceous era. It was found preserved in volcanic ash falls – a bit like Pompeii – captured curled up in a sleeping position very similar to how a lot of birds roost today.