Deforestation and hunting in Madagascar could see its lemur populations wiped out by 2040. Poverty on the island nation is rife and much of the forest habitat of the protected species has been cleared for rice growing. Efforts are now being made to develop new industries and agricultural methods which require less expansion into the forest. But will they be enough to save the lemurs? The BBC's science editor David Shukman has been to the island to find out.