Biological model building is a way of reconstructing extinct animal species. The model of a dodo (Raphus cucullatus), a large flightless bird on the island of Mauritius that went extinct around 1670, is an example of such a reconstruction. The basic information on which the model is based came from some skeletons and historic drawings and paintings. In a first step, the skeleton of the bird was put together, then a body with muscles was modelled in clay and finally cast in plaster. Feathers from chickens, ducks, swans and ostriches were arranged as in modern-day birds.