General Communication vs. Echolocation
All cetacean species are able to communicate for a variety of purposes. This includes mothers and calves staying in contact, group hunting, animals finding each other over a large area, and males sending messages of aggression to other males. However, odontocetes are also able to create sounds to echolocate, so they can find food and navigate. All of this communication, including echolocation, is done without vocal chords. Exactly how this happens is still being studied, especially for the baleen whales.
Illustration Credit: David Blanchette, NBWM docent