orcaholic1: Like the orca and other toothed whales, do baleen whales like the blue and humpback whales use echolocation?
Peter Gros: Sperm whales, like killer whales, produce precisely spaced echolocation clicks called "usual" clicks that are ititerated at about two clicks per second. Also in their repertoire are streams of clicks known as "creaks," because together they make a creaking sound. They are used in social situations called codas, or in foraging perhaps to home in on potential prey. "Ringing" slow clicks produced around every six seconds are characteristics of large males. It is thought slow clicks advertise a breeding male's presence. Sperm whales are a notable exception to other social toothed whales in that their sounds consist almost entirely of clicks rather than whistles as made by dolphins.

It appears that baleen whales, like the blue and the humpback, do not use echolocation, though scientists are still looking into this.