The Auroch is the European bison which died out in the 1600s. Their shape is recognisable in the drawings in the cave in Niaux and others. They were aggressive, often revered and the prehistoric people did not eat them.
A zoologist in Germany tried to recreate the breed using other similar breeds. This was part of a hankering for the past, and as part of the Nazi vision.
This is not an Auroch, but a bison at Porte Lympe Zoo Park in Kent.