The illegal trafficking of wildlife and animal products is the third largest criminal industry in the world where black rhinos are particularly prized by poachers.br br Numbers have dwindled from 100,000 in the 1960s to less than 4,000 today but now a former soldier is using his military skills honed in Iraq, to train a group of green rangers to save them.br br In a military base in the middle of a game reserve a 'green army' is trying to turn the tide, having already caught poachers armed with AK- 47s, axes, knives and machetes.