Sophie Lanfear, who produced and directed the episode, has said the walrus scenes were the hardest things she's ever had to witness or film in her career. She said, "I really wasn't prepared for the scale of death... They basically walk themselves off a cliff. Their depth perception hasn't evolved to deal with a cliff situation, nor have they evolved to work out how to get back the way they came. So it's just tragic. It's absolutely heartbreaking."