This is the first stage. They’re simple, single filaments, found in dense forests and unrecognisable as feathers. They’re different from the hairs of mammals because they don’t have any scales along their length. Nor are tubes from fungi or plants for they lack the thick cell walls that these groups have. They look a lot like the downy “dino-fuzz” that covered Sinosauropterx, the first dinosaur to be found with evidence of feathers. Sinosauropteryx’s fuzz was largely a reddish-brown colour, while those found in the amber ranged from dark to almost transparent.

In the second stage, the filament has turned into a cluster of ‘barbs’. In a modern feather, the barbs branch off from a central stalk or ‘rachis’ but