Photo by BrianSkerry / Secrets of the Whales / A beluga whale swims with a small stone in his mouth in the shallow coastal waters of the Canadian Arctic. The whale will swim with the stone for a brief time, drop it, and then it will often be picked up by another whale. Game play like this is an example of both high cognition in animals and of culture. Beluga whales are highly social and have complex cultures and ancestral traditions. Disney+ original series Secrets of the Whales, from NatGeo, is streaming this Earth Day, April 22, on DisneyPlus. In addition, my book of the same name is on sale now wherever books are sold. My work on whales is also featured in the May issue of National Geographic magazine, the Ocean Issue, available online now. Learn more about all three at Nat Geo's Planet Possible hub, our newest initiative, which aims to inform, inspire and enable consumers to live more lightly on the planet: natgeo.com/planet (link in bio). Follow me at BrianSkerry to keep up with...