Underwater photographer Tony Wu has had an essay detailing the back story to his stunning image of a group of sperm whales (Physeter macrocephalus) in Outdoor Photographer magazine. The image was taken off the Eastern Sri Lankan coast.

In the article Tony comments:

“I’m not sure that anyone fully understands why sperm whales, which are the largest of the toothed whales, congregate like this. I can say with a measure of confidence from repeated encounters of this nature, however (though involving far fewer whales, of course), that these events are social gatherings. The water is inevitably filled with a staggering cacophony of sound—clicking, clacking, snapping, popping, buzzing, squealing. The whales rub against one another, appearing to luxuriate in tactile exuberance. And, for whatever reason, they often defecate so much that the water becomes opaque, with the ocean taking on the texture and consistency of an oil slick. The one thing I always try to remember in these situations is: “Don’t drink the water.””