As the team reveal in the journal Antiquity, they targeted Creswell Crags because its caves are known to have been occupied in palaeolithic times. In the nineteenth century, archaeologists discovered a 12,000-year-old bone needle in a cave called Church Hole. And it is in this cave that Bahn and Pettitt discovered the two engravings, both of a style similar to the cave art of France and Spain. As for the two birds carved on the wall of Church Hole, one appears to be a crane or swan, the other a bird of prey. The other engraving is probably of an ibex, an animal not thought to have existed in Britain. The engraving may represent a rare sighting of an ibex that had strayed from southwest Europe.