The humpback whale is known for its loud haunting songs, which can be heard 20 miles away. According to BBC
However, new recordings show mothers and calves "whisper" to each other, seemingly to avoid attracting predators.
The quiet grunts and squeaks can be heard only at close range.
By calling softly to its mother, the calf is less likely be overheard and preyed on by killer whales, scientists believe.
Dr Simone Videsen is part of a team of scientists who tracked eight baby whales and two mothers to learn more about the first months of a humpback whales life.