What makes this video so spectacular is not only the whales, but how ecstatically the kayaker expresses his wonder!
In 2017, The Sun reports, Paul English, a Scottish journalist, was kayaking in the Churchill River in Manitoba. Belugas approached him a friendly manner and responded to his singing by coming closer and nudging his boat.
English then put on scuba gear and went for a swim with the whales. As this video from The Dodo demonstrates, he sang to them through his mouthpiece. The belugas responded to what they probably heard as gibberish by singing back to him!
-via Nag on the Lake