Acoustic studies are a form of wildlife monitoring. The sound study completes data collected by video photos or GPS. Bioacoustics has been strengthened to analyze biodiversity in each ecosystem. This science is called eco-acoustics. The first studies of sounds applied to ecology began in 1960 on birds and insects. Eco-acoustics are very useful when visual observation or satellite visual monitoring are ineffective. Tropical forests are the perfect example. Indeed, the vegetation cover is too large to be able to count species. Bioacoustics is able to count species as well as individuals. Each individual has his vocal signature, like humans. These studies make it possible to locate individuals. The sound isn’t received at the same time by the different microphones. This shift is used to triangulate the position of the transmitter.