A reclusive billionaire whose family owns the Mars confectionery empire has emerged as a determined opponent of the energy industry's plans to develop one of America's last wilderness states. Forrest E Mars Jr, the 75-year-old former chief executive of Mars Inc, has drawn on his $14 billion fortune to fire off a clutch of lawsuits to prevent drilling for natural gas and coal on his 82,000-acre Diamond Cross ranch near the town of Birney in south-eastern Montana. Under threat: The Diamond Cross ranch in Montana The state is famous for its "Big Sky" and breathtaking scenery but, despite its natural...