Human communities have a long history of responding ruthlessly but with only superficial justification to perceived competitors sharing the natural world. Predatory birds and mammals were viewed with suspicion from early times. In Britain the largest of these, the Brown Bear, Ursus arctos, was probably exterminated by the 10th century. The Wolf, Canis lupus, was sytematically persecuted throughout medieval times and was probably extinct in England by the end of the 14th century.