Watch Online Free on Watchseries. The secret life of hippos is revealed in this award-winning documentary, which follows divers into the waters of Tanzania's National Reserve. For the first time, cameras capture on film the astonishing underwater habits of these surprising creatures. A rare look at an essential part of hippo life, filmmakers Craig Huxley and Jean-Christophe Jeauffre's captivating documentary earned the Jules Verne Adventure Film Festival Audience Award.