Mapping trees can help count endangered lemurs. Duke Today, August 30, 2018. Putting a figure on the number of endangered lemurs left in the wild isn’t easy, but Duke University researchers say one clue might help: the plants they rely on for food. Bamboo lemur populations in their native Madagascar may have shrunk by half over the last two decades; red-fronted brown lemurs by as much as 85 percent. But numbers for other lemur species may not be as low as feared, new models suggest.