Actually we still have it, the Aurochs. It is the Spanish fighting cattle, and in France we also have big herds of it in the Camargue.

Reconstructing an original Aurochs is not difficult, but we no longer have the terrain for it. In Germany attempts have been made to keep Wisent in the wild. A disaster in our densely populated areas and the herds are too small so there are many genetic problems.

It is better to protect species that still exist before experimenting with species that are more or less extinct.