An elderly brown bear in the Pyrenees is facing castration or segregation amid fears that his sexual dominance is threatening the species’ survival in the region by limiting genetic diversity.

Pyros, one of the oldest of the 30 or so bears who roam the mountains between France and Spain, is the father, grandfather or great-grandfather of nearly all of the cubs born in the Pyrenees over the past two decades. There are four other males in the colony – only one of them is not related to Pyros – and none of them have fathered any offspring.

Spanish officials said they were being forced to decide between castration or segregation for Pyros after the recent birth of a cub who was both his daughter and grand-daughter.