Abstract
Recent studies using a variety of acoustic recording systems have shown that many beaked whale species produce frequency-modulated (FM) upsweep echolocation pulses that appear to be species-specific. For about half of the currently described species, concurrent visual sightings have identified which species are most likely to be the source of each of the FM pulse types. Several FM pulse types have been described and attributed to beaked whales but are not yet attributed to source species.