These calls were recorded on the morning of Jan 5, 2018 at one of our research sites in Southeast Texas. We do not know what they are. We have tried to isolate the sound, as the roars are fain in the background. Please turn up your volume to hear them. There are four of them, and I indicate with the cursor on the spectrogram where they each are. There are no known animals in this region that make sounds like this, to our knowledge. Any help is greatly appreciated in identifying these calls. The raw audio can be supplied upon request.