National Geographic : 1984 Aug
Eavesdropping on a killer whale conversation,John Ford (left) studies sounds made by different groups. Each pod, he discovered, has its own repertoire of noises. Some are shared with other pods, and some are uniquely their own. There are clicks used in echolocation,whistles used in social situations such as sexual activity or play, and pulsed calls, like the screechingof a rusty hinge, probably used to keep track of one anotherduring travel or foraging for food. The call of a killer like this one (below) may be heard by others at leastfive miles away. Whales in transientpods, however, are almost silent, perhaps to sneak up on prey.