Simon's research at the Durrell Institute of Conservation and Ecology includes the genetics, history and ecology of lions in North Africa. He also has other interests involving big cats, reptiles & birds, with current collaborations with researchers across the globe. Simon developed the zoo studbook for lions originating from the King of Morocco's collection. The studbook is used by the European Association of Zoos & Aquaria (EAZA) and currently supports the monitoring and transfer of lions for conservation breeding. Simon also works on leopard & tiger conservation and human-wildlife conflict in the Middle East, East Africa and South Asia.