"Brenda McCowan, a professor at the UC Davis School of Veterinary Medicine, explains that contact calls are similar to human greetings. Whales use them to call other whales or to inform each other of their location. Fred Sharpe, co-author and lead researcher at the Alaska Whale Foundation, said: “It is one of the most common signals in the humpback whale's social vocal repertoire.”"

"Twain was reported to swim towards the scientists' boat and circle it. For the next 20 minutes, the team sent the same contact call 36 times with varying intervals, and Twain responded to the calls each time, even very similar to the intervals. The results were reported to show that if the scientists waited 10 seconds before calling back to Twain, he would wait 10 seconds before answering, Brenda stated."