X-Roar

This recording from 2017 is actually of two individuals and was recorded not long after the team had loudly broadcasted playbacks of great ape vocalizations. The roars may well have been intended to defend territory through intimidation. The team in the field at the time—Echo team—only heard the first two vocalizations and never heard the third until they performed a field analysis of the audio recording the next day. Apparently, the audio recorder picked up the third roar.