Wrege's microphones also pick up other noises of the rainforest -- chimpanzees, birds and, sadly, the sounds of poaching. He has recovered audio that records gunshots and the sounds of poachers butchering forest elephants, a horrific episode, even without a visual.
Forest elephant poaching is one of the biggest poaching epidemics in the world -- according to estimates, there are about 100,000 forest elephants alive today, down from 500,000 in 1993. On average, 100 forest elephants are being killed daily. Like other elephant species, forest elephants are prized for their ivory, which can sell for $1,300 a pound on the black market.
But, Wrege hopes, this technology, if developed, could be used as a real-time poaching alarm for rangers and conservationists. While it can do little to prevent a poaching attack from happening, the mics could alert authorities when an attack happens, so they can try to catch the poachers.
Despite the poaching problem, Wrege maintains that all is not lost for forest elephants. In fact, compared to other elephants, he believes the species has "the best shot of living a normal, evolved lifestyle."
"There are plenty of reasons to not have much hope,'' he said. "But there's still a chance."