Clark can move a cursor around a screen and listen in on different areas of the North Atlantic. If he hears a whale singing, he can fix its location and position it in space and time and observe animals that are many tens of miles apart – cohorts of humpback singers moving coherently – and watch the collective migration of species in large portions of the ocean basin. “So if I am a whale off Newfoundland, I can hear a whale off Bermuda,” says Clark.