Greater bulldog bats emit echolocation signals that are either at constant frequency (CF), frequency-modulated (FM) or a combination of the two (CF-FM). The longest signals are the pure CF signal which typically last 13.3 ms but can go as long as 17 ms. CF-FM signals have CF followed by an FM. In a CF-FM signal, the CF are typically 8.9 ms with a frequency of 52.8–56.2 kHz while the FM ranges up to 3.9 ms with 25.9 kHz bandwidth. Bulldog bats have two kinds of signal when flying. In one, the CF pulses begin at 60 kHz of frequency and may fall no further than 50 kHz. The second type has the CF starting at a frequency of 60 kHz and then falls for more than a single octave.
