We don't know just what each call means, but orcas communicate when they're separated, when they meet another pod, or when deciding where to go or what to do next. A pod's group of sounds is called a dialect. Even though pods meet regularly and mingle, each keeps its own unique dialect. However, dialects do change over time--very slowly.
Orcas fnid prey and navigate by sending out clicks and buzzes into the dark, murky water, and waiting for the echo to bounce back. This process is called echolocation. Sound travels about five times faster through water than air, so it's a quick way to determine what's out there.
